Cardioids crossed at 90 degrees

[James Boyk]

Somone mentioned a new stereo mike that embodies coincident cardioids crossed at 90 degrees. I find it odd to use this arrangement, since the stereo given by this arrangement is much too narrow, and is also irregular in movement across the stage. This has
been noted by others in the group in other contexts, and is also shown in the stereo miking demo recording made in my lab.

On the other hand, what should the mike be instead? If it were ORTF--arguably the best you can do if you're confined to cardioids--it would be physically more awkward, and probably more vulnerable to damage. But perhaps 120 degrees would have been usefully
better. As long as they were at it, though, why not make a coincident, 90-degree pair of condenser....figure-8's? Even go all the way and make single-diaphragm fig-8's, like the Schoeps MK-8.

James Boyk

[Scott Dorsey]

James Boyk <boyk@caltech.edu> wrote:
>Somone mentioned a new stereo mike that embodies coincident cardioids crossed at 90 degrees. I find it odd to use this arrangement, since the stereo given by this arrangement is much too narrow, and is also irregular in movement across the stage. This has
been noted by others in the group in other contexts, and is also shown in the stereo miking demo recording made in my lab.
>
>On the other hand, what should the mike be instead? If it were ORTF--arguably the best you can do if you're confined to cardioids--it would be physically more awkward, and probably more vulnerable to damage. But perhaps 120 degrees would have been usefull
y better. As long as they were at it, though, why not make a coincident, 90-degree pair of condenser....figure-8's? Even go all the way and make single-diaphragm fig-8's, like the Schoeps MK-8.

With a single point stereo mike, you are confined to either an M-S pair or
to cardioids. Something like an ORTF pair is too cumbersome to be practical;
it kills the convenience that is the main reason for using a stereo mike.

In the case of cardioids, the angle should be adjustable, as in the Nevaton
microphone. But if it can't be adjustable, 120' seems like a good start.

There are some coincident figure-8 microphones out there. Most of them
are ribbon designs, though, since it's hard to make good small condenser
figure-8s.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[David Spearritt]

Narrow stereo is more interesting than mono. The Rode NT4 is the priced like
a mono mic but sounds much better being crossed cardioids at 90. I agree
that for a single point stereo mic to create an accurate linear image and
positioning of sources it is not the best, but I think this is not its
intended purpose.

Regards
David

"James Boyk" <boyk@caltech.edu> wrote in message
news:bi3afj$t2g$1@naig.caltech.edu...
> Somone mentioned a new stereo mike that embodies coincident cardioids
crossed at 90 degrees. I find it odd to use this arrangement, since the
stereo given by this arrangement is much too narrow, and is also irregular
in movement across the stage. This has been noted by others in the group in
other contexts, and is also shown in the stereo miking demo recording made
in my lab.
>
> On the other hand, what should the mike be instead? If it were
ORTF--arguably the best you can do if you're confined to cardioids--it would
be physically more awkward, and probably more vulnerable to damage. But
perhaps 120 degrees would have been usefully better. As long as they were at
it, though, why not make a coincident, 90-degree pair of
condenser....figure-8's? Even go all the way and make single-diaphragm
fig-8's, like the Schoeps MK-8.
>
> James Boyk
>

[Scott Dorsey]

David Spearritt <spam@just.try.it> wrote:
>Narrow stereo is more interesting than mono. The Rode NT4 is the priced like
>a mono mic but sounds much better being crossed cardioids at 90. I agree
>that for a single point stereo mic to create an accurate linear image and
>positioning of sources it is not the best, but I think this is not its
>intended purpose.

What intended purpose does it HAVE then?
--scott


--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Jim Weld]

If you're not strictly talking about small cardioids, then you have a few
figure-8 stereo mics out there. I have used the Neumann tube sm-69 (there
is also a fet version still available). There are also vintage AKG c-442
and c-34(c34 is a small capsule). These are all dual-diaphragm
multi-pattern mics. Blumlein or modified Blumlein is my favorite stereo
miking arrangement. For the coincident pair in figure 8, I get a very
natural left-to-right image with less than 90 degrees spread. (usually
about 75-80 degrees)

Single diaphragm mics like the Schoeps roll-off very quickly on the bottom,
but otherwise probably sound pretty good.

Jim Weld

"James Boyk" <boyk@caltech.edu> wrote in message
news:bi3afj$t2g$1@naig.caltech.edu...
> Somone mentioned a new stereo mike that embodies coincident cardioids
crossed at 90 degrees. I find it odd to use this arrangement, since the
stereo given by this arrangement is much too narrow, and is also irregular
in movement across the stage. This has been noted by others in the group in
other contexts, and is also shown in the stereo miking demo recording made
in my lab.
>
> On the other hand, what should the mike be instead? If it were
ORTF--arguably the best you can do if you're confined to cardioids--it would
be physically more awkward, and probably more vulnerable to damage. But
perhaps 120 degrees would have been usefully better. As long as they were at
it, though, why not make a coincident, 90-degree pair of
condenser....figure-8's? Even go all the way and make single-diaphragm
fig-8's, like the Schoeps MK-8.
>
> James Boyk
>

[James Boyk]

Try Blumlein (coincident figure-8's crossed at 90 degrees) with ribbons sometime. It is a revelation after using condensers. I would go so far as to say that Blumlein can't really be done with condensers; not because they're condensers, mind you, but becau
se they have off-axis anomalies due to their disk-shaped relatively large diaphragms.

James Boyk

[James Boyk]

Scott Dorsey wrote: With a single point stereo mike, you are confined to either an M-S pair or to cardioids.

I don't follow this. They could certainly be hyper-cardioids or super-cardioids, or figure-8's. Did you mis-state what you meant?

James Boyk

[Scott Dorsey]

James Boyk <boyk@caltech.edu> wrote:
>Try Blumlein (coincident figure-8's crossed at 90 degrees) with ribbons sometime. It is a revelation after using condensers. I would go so far as to say that Blumlein can't really be done with condensers; not because they're condensers, mind you, but beca
use they have off-axis anomalies due to their disk-shaped relatively large diaphragms.

This is precisely why the Pearl and Milab guys have gone to those goofy
rectangular diaphragms. Kavi Alexander built a stereo mike using them, and
some of the later incarnations sounded pretty good.

What is with the lack of carriage returns? Your messages were always formatted
properly before. Has something changed today?
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Scott Dorsey]

In article <bi3gg3$308$2@naig.caltech.edu>,
James Boyk <boyk@caltech.edu> wrote:
>Scott Dorsey wrote: With a single point stereo mike, you are confined to either an M-S pair or to cardioids.
>
>I don't follow this. They could certainly be hyper-cardioids or super-cardioids, or figure-8's. Did you mis-state what you meant?

Well, I was considering hypercardioids and supercardioids as basically being
subsets of that whole cardioid thing. Either way, it's a coincident pair of
directional mikes.

Figure-8s are sort of a different and third sort of thing.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Jim Weld]

Thanks for the info. Once again I misunderstood the post. Also, I like a
"modified Blumlein" pattern using two figure eight mics with about 6-7
inches between capsules. Also aimed about 75 degrees. Good at a distance.


"James Boyk" <boyk@caltech.edu> wrote in message
news:bi3gd7$308$1@naig.caltech.edu...
> Try Blumlein (coincident figure-8's crossed at 90 degrees) with ribbons
sometime. It is a revelation after using condensers. I would go so far as to
say that Blumlein can't really be done with condensers; not because they're
condensers, mind you, but because they have off-axis anomalies due to their
disk-shaped relatively large diaphragms.
>
> James Boyk
>

[James Boyk]

Scott Dorsey wrote: This is precisely why the Pearl and Milab guys have gone to those goofy
rectangular diaphragms. Kavi Alexander built a stereo mike using them, and
some of the later incarnations sounded pretty good.

The problem is created not by the diaphragm's shape but by its dimensions. Unless the rectangular condensers are very narrow--as narrow as ribbons--they will still have the same problem.


> What is with the lack of carriage returns? Your messages were always formatted
> properly before. Has something changed today?

Hmm. Sorry. I haven't changed anything. Mail I'm receiving today looks funny, too.

James Boyk

[James Boyk]

Jim Weld wrote: > Thanks for the info. Once again I misunderstood the post. Also, I like a
> "modified Blumlein" pattern using two figure eight mics with about 6-7
> inches between capsules. Also aimed about 75 degrees. Good at a distance.

More power to you, but puh-leeze don't call it a Blumlein of any sort. It has nothing to do with Blumlein.

James Boyk

[James Boyk]

Scott Dorsey wrote: Well, I was considering hypercardioids and supercardioids as basically being
subsets of that whole cardioid thing.

Sure.


> Figure-8s are sort of a different and third sort of thing.

That was my point. No reason the NT4 couldn't have been fig-8's.


James Boyk

[Bob Ross]

James Boyk wrote:

> No reason the NT4 couldn't have been fig-8's.

except perhaps for the omission of that extra zero in the price point?

/Bob Ross

[ScotFraser]

<< Something like an ORTF pair is too cumbersome to be practical;
it kills the convenience that is the main reason for using a stereo mike. >>

The Schoeps ORTF body is pretty small & convenient. I believe it's the MTSC-3
model, & takes the Collette series capsules.



Scott Fraser

[James Boyk]

Bob Ross wrote: except perhaps for the omission of that extra zero in the price point?


Are 8's inherently more expensive to make than cardioids? Why?


James Boyk

[Bob Ross]

James Boyk wrote:

> Are 8's inherently more expensive to make than cardioids?

Apparently

> Why?

I couldn't tell you. Conjecture suggests that the (relatively) more uniform polar
response at all frequencies that is typical of bidirectional mics doesn't come cheap, but
that's just a guess. Perhaps Dave Josephson or Taylor Johnson or Skipper Wise or (etc
etc) would care to chime in on this issue?

/Bob

[Scott Dorsey]

Bob Ross <b.ross@verizon.net> wrote:
>James Boyk wrote:
>
>> No reason the NT4 couldn't have been fig-8's.
>
>except perhaps for the omission of that extra zero in the price point?

The way I figure it is that if Schoeps can't make a good small diaphragm
figure-8 at THEIR price point, how can we expect Rode to do so?
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Scott Dorsey]

ScotFraser <scotfraser@aol.com> wrote:
><< Something like an ORTF pair is too cumbersome to be practical;
>it kills the convenience that is the main reason for using a stereo mike. >>
>
>The Schoeps ORTF body is pretty small & convenient. I believe it's the MTSC-3
>model, & takes the Collette series capsules.

Okay, YOU can hang off the back of a motorcycle with it next time.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Scott Dorsey]

James Boyk <boyk@caltech.edu> wrote:
>Bob Ross wrote: except perhaps for the omission of that extra zero in the price point?
>
>Are 8's inherently more expensive to make than cardioids? Why?

For condenser mikes? Yes, when they are even possible to make.
Matching between the two sides is extremely critical.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[James Boyk]

The odd thing is that Blumlein showed how to use spaced omni's with a "Blumlein shuffler" to get correct stereo; and this technique offers remarkable power & flexibility; yet despite all the people who like to use spaced omni's, the shuffler doesn't exist
commercially. There are things called shufflers, but they're not the Blumlein shuffler.

James Boyk

[Bob Cain]

Scott Dorsey wrote:
>
> In article <bi3gg3$308$2@naig.caltech.edu>,
> James Boyk <boyk@caltech.edu> wrote:
> >Scott Dorsey wrote: With a single point stereo mike, you are confined to either an M-S pair or to cardioids.
> >
> >I don't follow this. They could certainly be hyper-cardioids or super-cardioids, or figure-8's. Did you mis-state what you meant?
>
> Well, I was considering hypercardioids and supercardioids as basically being
> subsets of that whole cardioid thing. Either way, it's a coincident pair of
> directional mikes.
>
> Figure-8s are sort of a different and third sort of thing.

Actually not. The whole family is the superpostion of a
figure 8 (differential pressure) component with an omni
(pressure) component. When the sensitivity of the omni
component is zero it's a figure 8. When it's the same as
the fig 8, the composite is a cardiod. When the omni
sensitivity is greater than the fig 8, it's a sub-cardiod
and when the omni sensitivity is less than the fig 8, it's a
hyper-cardiod.


Bob
--

"Things should be described as simply as possible, but no
simpler."

A. Einstein

[Bob Cain]

James Boyk wrote:
>
> The odd thing is that Blumlein showed how to use spaced omni's with a "Blumlein shuffler" to get correct stereo; and this technique offers remarkable power & flexibility; yet despite all the people who like to use spaced omni's, the shuffler doesn't exis
t commercially. There are things called shufflers, but they're not the Blumlein shuffler.
>
> James Boyk

The Waves S1 Stereo Imager plugin claims to implement true
Blumlein shuffling. See:

http://www.waves.com/htmls/prods/indi/s1.html



Bob
--

"Things should be described as simply as possible, but no
simpler."

A. Einstein

[Roger W. Norman]

Figure of 8 mics require dual capsules, which in a small condenser, is
pretty hard to make. And they aren't in a front facing configuration, which
is about the only thing a small condenser will allow.

I don't see a problem with coincident mics at 90 degrees. I use this
configuration often for acoustic grand piano without a problem (unless the
piano player hums while playing) in anything resembling too narrow of a
stereo field. As far as the NT4, I can easily see using it in place of two
mics and a stereo mic bar, but then if that's what one would want for
greater stereo separation then there's the NT5s or any other decent to great
small condenser mics, or large condensers if they get the sound you want.
It's just all part of an engineer's tool kit, meaning technique, not just
equipment. I just did a flamenco influenced acoustic guitar player with a
pair of large diaphragm condensers set up in an over/under 90 degree
coincident pair at 2 feet and got a great recording. Were I to have backed
up maybe to 12 feet for a room miking situation I may have moved it to 120
degrees, but it depends on what's going to be playing in the room.

There's also nothing wrong with using a fixed 90 degree setup like the NT4
for drum overheads assuming one gets them up high enough to represent what
the drummer hears, and assuming that the mic pre can drive the mic well
enough. A stereo condenser would work better in this situation with lesser
quality mic pres than would a pair of ribbons, for example, simply due to a
ribbon's lower output.

Again, it's just another tool available to an engineer. It's then his/her
job to figure out which tool does the best job.

--


Roger W. Norman
SirMusic Studio
Purchase your copy of the Fifth of RAP CD set at www.recaudiopro.net. See
how far $20 really goes.




"James Boyk" <boyk@caltech.edu> wrote in message
news:bi3soc$8d7$1@naig.caltech.edu...
> Bob Ross wrote: except perhaps for the omission of that extra zero in the
price point?
>
>
> Are 8's inherently more expensive to make than cardioids? Why?
>
>
> James Boyk
>

[James Boyk]

Roger W. Norman wrote: Figure of 8 mics require dual capsules, which in a small condenser, is
> pretty hard to make. And they aren't in a front facing configuration, which
> is about the only thing a small condenser will allow.


I don't follow this last remark.



> I don't see a problem with coincident mics at 90 degrees. I use this
> configuration often for acoustic grand piano without a problem (unless the
> piano player hums while playing) in anything resembling too narrow of a
> stereo field.


The problem isn't with mikes coincident at 90 degrees, it's with *cardioids* at 90. Their sound field is narrow, and the imaging across that field is uneven; that is, evenly spaced sources come out sounding not evenly spaced. Cardioids at 120 gives an imag
e width that comes closer to the truth, though the uneven spacing is then more obvious. If one must use cardioids, it would seem that ORTF is perhaps the best array--speaking only in terms of imaging.



> ...A stereo condenser would work better in this situation with
lesser quality mic pres than would a pair of ribbons, for example,
simply due to a ribbon's lower output.


Some ribbons have output levels similar to studio dynamics, and any professional preamp ought to have perfectly good S/N at such levels.


James Boyk

[Hal Laurent]

"Scott Dorsey" <kludge@panix.com> wrote in message
news:bi48jj$n4k$1@panix2.panix.com...

> The way I figure it is that if Schoeps can't make a good small diaphragm
> figure-8 at THEIR price point, how can we expect Rode to do so?

What's wrong with the Schoeps figure-8?

Hal Laurent
Baltimore

[Scott Dorsey]

Hal Laurent <laurent@charm.net> wrote:
>"Scott Dorsey" <kludge@panix.com> wrote in message
>news:bi48jj$n4k$1@panix2.panix.com...
>
>> The way I figure it is that if Schoeps can't make a good small diaphragm
>> figure-8 at THEIR price point, how can we expect Rode to do so?
>
>What's wrong with the Schoeps figure-8?

It's probably the best there is, but it doesn't sound anywhere near as clean
in the midrange as the rest of the line.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[ScotFraser]

<< Figure of 8 mics require dual capsules, which in a small condenser, is
pretty hard to make. And they aren't in a front facing configuration, which
is about the only thing a small condenser will allow. >>

Neumann & Schoeps both have small diaphragm side address figure 8 capsules
available, for the KM100 & Collette series, respectively.


Scott Fraser

[ScotFraser]

<< Okay, YOU can hang off the back of a motorcycle with it next time. >>

Only seeing eye motorcycles for the visually impaired are allowed in the
concert hall.


Scott Fraser

[Roger W. Norman]

Right, side address as opposed to the standard pencil type of cardioid/omni
mic, which I guess James didn't catch what I meant.

--


Roger W. Norman
SirMusic Studio
Purchase your copy of the Fifth of RAP CD set at www.recaudiopro.net. See
how far $20 really goes.




"ScotFraser" <scotfraser@aol.com> wrote in message
news:20030822114550.28426.00000503@mb-m18.aol.com...
> << Figure of 8 mics require dual capsules, which in a small condenser, is
> pretty hard to make. And they aren't in a front facing configuration,
which
> is about the only thing a small condenser will allow. >>
>
> Neumann & Schoeps both have small diaphragm side address figure 8 capsules
> available, for the KM100 & Collette series, respectively.
>
>
> Scott Fraser

[Scott Dorsey]

ScotFraser <scotfraser@aol.com> wrote:
><< Okay, YOU can hang off the back of a motorcycle with it next time. >>
>
>Only seeing eye motorcycles for the visually impaired are allowed in the
>concert hall.

In the concert hall, you don't need a stereo mike. The reason that the
stereo mike exists is for the convenience in field recording. It is much
easier to boom a stereo mike or to hang it off a motorcycle or biplane
when people need to do that kind of thing.

In a concert hall, a stereo mike basically gives more limitations for more
money without any real advantages over a stereo pair.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[James Boyk]

Roger W. Norman wrote: > Right, side address as opposed to the standard pencil type of cardioid/omni
> mic, which I guess James didn't catch what I meant.

Tnx for clarification. -jb

[James Boyk]

Scott Dorsey wrote:
> In a concert hall, a stereo mike basically gives more limitations for more
> money without any real advantages over a stereo pair.

Less visual obstruction?

James Boyk

[William Sommerwerck]

Not really. I've recorded both with two mics on a bar and a SoundField mic. The
larger size of the SoundField is at leas as visually disturbing as the two
smaller, separate mics.

> Less visual obstruction?

[Benjamin Maas]

"Scott Dorsey" <kludge@panix.com> wrote in message ...
>
> In a concert hall, a stereo mike basically gives more limitations for more
> money without any real advantages over a stereo pair.
> --scott


I disagree with this comment... I find that stereo mics (especially the
ones with multiple patterns for each capsule) are some of the most versatile
mics that I use. My personal fav. is an AKG 426 which is large diaphragm,
but the C-34 is quite good as a small dia. mic. The Schoeps CMT 201 (?) is
another favorite of mine. It is a pain to use as it requires a 12v. phantom
supply, but beyond that, it is a great mic.

Besides the ability to choose a pickup pattern that works for a given
situation (Blumlein, M-S, X-Y or some hybrid), they often make the
performers happy because they are very unobtrusive. I find this to be
especially important when I'm recording vocal recitals. Most vocalists get
really uptight when there is too large of a microphone in front of them...
It "gets in the way of their communication with the audience." I find that
they complain the least when I use a stereo mic.

--Ben


--
Benjamin Maas
Fifth Circle Audio
Los Angeles, CA
http://www.fifthcircle.com

[Ty Ford]

In Article <bi3afj$t2g$1@naig.caltech.edu>, James Boyk <boyk@caltech.edu> wrote:
>Somone mentioned a new stereo mike that embodies coincident cardioids crossed
at 90 degrees. I find it odd to use this arrangement, since the stereo given
by this arrangement is much too narrow, and is also irregular in movement
across the stage. This has been noted by others in the group in other
contexts, and is also shown in the stereo miking demo recording made in my lab.
>
>On the other hand, what should the mike be instead? If it were ORTF--arguably
the best you can do if you're confined to cardioids--it would be physically
more awkward, and probably more vulnerable to damage. But perhaps 120
degrees would have been usefully better. As long as they were at it, though,
why not make a coincident, 90-degree pair of condenser....figure-8's? Even
go all the way and make single-diaphragm fig-8's, like the Schoeps MK-8.
>
>James Boyk


Coincident XY @ 90 degrees works sometimes; sometimes it doesn't.

Regards,

Ty

For Ty Ford V/O demos, audio services and equipment reviews,
click on http://www.jagunet.com/~tford

[James Boyk]

Ty Ford wrote:
> Coincident XY @ 90 degrees works sometimes; sometimes it doesn't.

Do you mean cardioids? If so, the setup may "work," but it can't have correct imaging. Granted, this may not be the dominant consideration on every occasion; but it ought to be *a* consideration!

James Boyk

[Bob Cain]

James Boyk wrote:
>
> Ty Ford wrote:
> > Coincident XY @ 90 degrees works sometimes; sometimes it doesn't.
>
> Do you mean cardioids? If so, the setup may "work," but it can't have correct imaging. Granted, this may not be the dominant consideration on every occasion; but it ought to be *a* consideration!
>

Could you explain why it can't have correct imaging? It
contains orthogonal gradient components which is also the
basis of Ambisonics.


Bob
--

"Things should be described as simply as possible, but no
simpler."

A. Einstein

[James Boyk]

James Boyk wrote: Do you mean cardioids? If so, the setup may "work," but it can't have correct imaging. Granted, this may not be the dominant consideration on every occasion; but it ought to be *a* consideration!

Bob Cain wrote: Could you explain why it can't have correct imaging? It contains
orthogonal gradient components which is also the basis of Ambisonics.

One of the requirements is that, as the source moves across the stage, the sum of the two channels has to stay constant. With figure-8's, it's pretty close to doing so; and very close with +/- 30 degrees of center. If the figure-8 pattern were cosine^2, th
en the two channels would add perfectly to 1 at all angles, because one of them is cosine^2 and the other, being identical to the first but at right angles to it, looks like sine^2, and cos^2 + sin^2 is identically 1 at all angles, as you recall from high-
school geometry. Well, figure-8 is not cos^2, but for small angles (say up to 30 degrees either side of center), cos is a good approximation to cos^2.

The cardioid differs a lot from this; in particular, the two channels add up to too much at and near the center. Hence the narrowness of the image, which is shown as a practical matter on the stereo miking demo recording made in my lab. It's not a subtle e
ffect.

Ambisonics is a completely different story and involves an ENORMOUS amount of mathematical processing to the signal on both the record and playback ends.

James Boyk

[Kurt Albershardt]

Roger W. Norman wrote:
> Figure of 8 mics require dual capsules, which in a small condenser, is
> pretty hard to make.

Not necessarily--but single-diaphragm figure-eight condenser capsules
are very, very hard to make well. LF response suffers with small
diaphragms, but HF response suffers with larger ones--and there's the
problem of the backplate getting in the way of the sound from at least
one side.

[Kurt Albershardt]

James Boyk wrote:
>
> The problem isn't with mikes coincident at 90 degrees, it's with
> *cardioids* at 90. Their sound field is narrow

It's wider than that of a figure-eight.



> and the imaging across that field is uneven

As is the frequency response (uneven across the field) in almost all cases.

[James Boyk]

Kurt Albershardt wrote:

> James Boyk wrote: >> The problem isn't with mikes coincident at 90 degrees, it's with
>> *cardioids* at 90. Their sound field is narrow

> It's wider than that of a figure-eight.

Sorry, this is wrong in both theory and practice. Just listen to the relevant tracks on our stereo miking demo recording.



>> and the imaging across that field is uneven

> As is the frequency response (uneven across the field) in almost all cases.


Not with the best 8's.

James Boyk

[James Boyk]

Kurt Albershardt wrote:
> Not necessarily--but single-diaphragm figure-eight condenser capsules
> are very, very hard to make well. LF response suffers with small
> diaphragms, but HF response suffers with larger ones--and there's the
> problem of the backplate getting in the way of the sound from at least
> one side.


A convincing argument for using ribbons!


James Boyk

[Kurt Albershardt]

James Boyk wrote:

> Kurt Albershardt wrote:
>
>>> James Boyk wrote:
>>> The problem isn't with mikes coincident at 90 degrees,
>>> it's with *cardioids* at 90. Their sound field is narrow
>
>
>> It's wider than that of a figure-eight.
>
>
> Sorry, this is wrong in both theory and practice. Just listen to the
> relevant tracks on our stereo miking demo recording.

We seem to be talking at cross puropses here. The frontal pickup
pattern of a figure eight is more directional than that of a cardioid.

If you're using 'sound field' in a more psychoacoustic sense, then the
pattern of the mic is inexorably intertwined with its placement
releative to the other mic(s) and to the source.




>>> and the imaging across that field is uneven
>
>> As is the frequency response (uneven across the field) in almost all
>> cases.
>
>
> Not with the best 8's.

Sorry--I should have explicitly restated 'cardioids' on that one.

[James Boyk]

Ah. I thought you were saying that the stereo image of 90-crossed-8's (Blumlein) was narrowed than that of 90-crossed-cardioids, whereas the reverse is in fact the case. Of course we all know the shapes of the two patterns.


James Boyk

[Bob Cain]

James Boyk wrote:
>
> James Boyk wrote: Do you mean cardioids? If so, the setup may "work," but it can't have correct imaging. Granted, this may not be the dominant consideration on every occasion; but it ought to be *a* consideration!
>
> Bob Cain wrote: Could you explain why it can't have correct imaging? It contains
> orthogonal gradient components which is also the basis of Ambisonics.
>
> One of the requirements is that, as the source moves across the stage, the sum of the two channels has to stay constant.

With cards crossed at 90 degrees, the summed signal from
each on-axis direction has a gain of 1.50 while at the
center the gain is 1.71 which is a deviation of about 1.12
dB from the ideal you specify. I can't get too excited
about that to begin with and can manipulate it with M/S
matrixing methods to even it out to whatever degree sounds
right should I feel the need. I am still chewing on your
statement that equality at center and on each mic axis is a
requirement for correct imaging. Seems to me that speaker
placement, directivity and subtended listening angle will
have at least as much an effect as that on imaging and we
haven't even considered those reproduction issues.

I think this is beside the point in any event. For any kind
of real listening environment we don't yet know how to
record something and reproduce it "correctly" in space as
all the discussion on the surrsound mailing list will
clearly attest. I don't think it is possible, frankly, and
think most of the stuff going on is smoke and mirrors with a
lot of persuasive heuristics used to try and justify the
"correctness" of each proposed method. The best we can do
is create an illusion such that, when the listener suspends
his disbelief, he obtains an acoustic image that is
plausible and pleasant within reasonable expectations of
speaker placement and room characteristics. Coincident X/Y
with cards crossed at 90 degrees is just one of many ways of
accomplishing that satisfactorily.


Bob
--

"Things should be described as simply as possible, but no
simpler."

A. Einstein

[William Sommerwerck]

> I think this is beside the point in any event. For any kind
> of real listening environment we don't yet know how to
> record something and reproduce it "correctly" in space
> as all the discussion on the surrsound mailing list will
> clearly attest. I don't think it is possible, frankly, and
> think most of the stuff going on is smoke and mirrors
> with a lot of persuasive heuristics used to try and justify
> the "correctness" of each proposed method.

No offense, but you've obviously never heard Ambisonic recordings. I've actually
made them, and the sound is much closer to what you hear live than any other
speaker-based surround system.

[Peter B.]

James Boyk <boyk@caltech.edu> wrote in message news:<bi6q6i$k1h$1@naig.caltech.edu>...
> James Boyk wrote: Do you mean cardioids? If so, the setup may "work," but it can't have correct imaging. Granted, this may not be the dominant consideration on every occasion; but it ought to be *a* consideration!
>
> Bob Cain wrote: Could you explain why it can't have correct imaging? It contains
> orthogonal gradient components which is also the basis of Ambisonics.
>
> One of the requirements is that, as the source moves across the
stage, the sum of the two channels has to stay constant. With
figure-8's, it's pretty close to doing so; and very close with +/- 30
degrees of center. If the figure-8 pattern were cosine^2, then the two
channels would add perfectly to 1 at all angles, because one of them
is cosine^2 and the other, being identical to the first but at right
angles to it, looks like sine^2, and cos^2 + sin^2 is identically 1 at
all angles, as you recall from high-school geometry. Well, figure-8 is
not cos^2, but for small angles (say up to 30 degrees either side of
center), cos is a good approximation to cos^2.
>
> The cardioid differs a lot from this; in particular, the two channels add up to too much at and near the center. Hence the narrowness of the image, which is shown as a practical matter on the stereo miking demo recording made in my lab. It's not a subtle
effect.
>
> Ambisonics is a completely different story and involves an ENORMOUS amount of mathematical processing to the signal on both the record and playback ends.
>
> James Boyk


Does anyone know where the whole 90 degree angle for crossed
cardioids started? There really is a LOT of confusion on this issue.
I'm wondering if somebody published this in a book somewhere. I was
taught that (I don't remember where)and quickly figured out that it
results in a recording that is too strong in the center. Not too long
ago I was invited over to the house of an engineer friend of mine. He
just bought a matched set of mics and explained to me how he was going
to cross cardioids at 90 degrees. Another time I was out at a club
setting up for a recording when the sound guy came over to chat. I
found out that he worked for a major microphone company. We talked
about mics for awhile and he informed me that the angle between my
mics was too wide. He said that they should be crossed at 90 degrees.
I responded saying that the recording would come out with too strong
of a mono image. He then said that I would get too much sound being
reflected off of the side walls with my mics spread apart so far. The
conversation ended there because each of us had work to do. I kept my
angle.

My best guess at why this whole 90 degree thing started is because
people forget or do not understand the off axis response. Cardioid is
being taught as "picks up from the front" without taking into account
what the pattern name actually means. So with that in mind, yeah, I
can see how two mics that 'pick up sound from the front' would be bad
at 127 degrees + or - a few. I'd be recording all 'wall sound'. At 90
degrees the mics are pointed more at the performers so then I will be
picking up more of them and less "room sound".

On second thought, perhaps this all may boil down to it being much
easier to teach people 'picks up from the front' than explaining the
topic of mic patterns with basic trig terms. 'Picks up from the front'
will for all practical purposes work fine for close micing a single
source with a single mic... At least in the struggling band and church
band SR world.


Just some thoughts...

Peter

[David Satz]

Roger Norman wrote:

> Figure of 8 mics require dual capsules [ ... ]

That's simply not true. A dual-capsule design such as the Neumann KM 86,
or a dual-diaphragm design as in the Neumann KM 56 or KM 88, is certainly
possible--but so is a capsule design with a single diaphragm exposed on
both sides symmetrically, as the Schoeps MK 8 and Neumann AK 120.


> [ ... ] which in a small condenser, is pretty hard to make.

Well, it is pretty hard to make good microphones of any kind! But the
examples I gave above are all small condensers that are well known and
successfully used as bidirectional microphones over many years.


> And they aren't in a front facing configuration, which is about the
> only thing a small condenser will allow.

The situation with small and large condensers is exactly the same in
this respect.

One important use of figure-8 microphones is as the "S" microphone in
an M/S pair. In that application you aim the null plane of the figure-8
forward toward the center of the sound source. Directional patterns are
three-dimensional, so for M/S you can aim the tip of the microphone
directly at the center of the sound source if that's more convenient.


> I don't see a problem with coincident mics at 90 degrees. I use this
> configuration often [ ... ]

I've noticed that your whole discussion omits any consideration of the
directional pattern of the microphones you're using. But that's the
real issue here--the stereo image depends not just on the angle between
a coincident pair, but also on the directional pattern of the mikes.

This thread began with a discussion of crossed cardioids. A cardioid
is a blend of pressure and pressure-gradient response in a 50/50 mixture.
The pressure response is essentially omnidirectional (i.e. except at high
frequencies). Thus two coincident cardioids at _any_ included angle will
put out 50% the identical signal, due to their 50% pressure response.

Michael Williams has published a set of curves which show the spatial
distribution of apparent sound sources when they've been recorded with
various coincident and non-coincident microphone pairs and played back
on loudspeakers. What Prof. Boyk has said in this thread is precisely
supported by the Williams curves: with 90-degree coincident cardioids,
too much of the sound "bunches up" in the apparent center of the image.
That is only to be expected given the "nearly mono" nature of the pickup.

[Richard Kuschel]

>
> Does anyone know where the whole 90 degree angle for crossed
>cardioids started? There really is a LOT of confusion on this issue.
>I'm wondering if somebody published this in a book somewhere. I was
>taught that (I don't remember where)and quickly figured out that it
>results in a recording that is too strong in the center. Not too long
>ago I was invited over to the house of an engineer friend of mine. He
>just bought a matched set of mics and explained to me how he was going
>to cross cardioids at 90 degrees. Another time I was out at a club
>setting up for a recording when the sound guy came over to chat. I
>found out that he worked for a major microphone company. We talked
>about mics for awhile and he informed me that the angle between my
>mics was too wide. He said that they should be crossed at 90 degrees.
>I responded saying that the recording would come out with too strong
>of a mono image. He then said that I would get too much sound being
>reflected off of the side walls with my mics spread apart so far. The
>conversation ended there because each of us had work to do. I kept my
>angle.
>
> My best guess at why this whole 90 degree thing started is because
>people forget or do not understand the off axis response. Cardioid is
>being taught as "picks up from the front" without taking into account
>what the pattern name actually means. So with that in mind, yeah, I
>can see how two mics that 'pick up sound from the front' would be bad
>at 127 degrees + or - a few. I'd be recording all 'wall sound'. At 90
>degrees the mics are pointed more at the performers so then I will be
>picking up more of them and less "room sound".
>
> On second thought, perhaps this all may boil down to it being much
>easier to teach people 'picks up from the front' than explaining the
>topic of mic patterns with basic trig terms. 'Picks up from the front'
>will for all practical purposes work fine for close micing a single
>source with a single mic... At least in the struggling band and church
>band SR world.
>
>
>Just some thoughts...
>
>Peter
>
>

Don't know where it started, maybe it was just a starting point.

I seldom use the XY any more for miking at a distance, and I tend to make the
angle quite a bit greater. As far out as 130 degrees if I need to get rid of
the build up in the center.




Richard H. Kuschel
"I canna change the law of physics."-----Scotty

[James Boyk]

Well, I don't know how to answer. You cannot judge the matter by looking at two 3-digit numbers and saying Gee, they're not so very different from each other. You can judge only by listening. The question was whether 90-coincident-cardioids image correctly
. They don't; they don't come close. I suggest that the virtues of the best stereo arrays, and the defects of others, will become more vivid to you if you listen to our demo recording. It's your privilege not to care about imaging---though personally I thi
nk it's of fundamental importance to successful recording, for a reason I haven't gone into here---but facts are facts; and the fact is that 90-coincident-cardioids don't work well in theory or in practice.

James Boyk

[James Boyk]

Terminology: So far as I know, "XY" refers to any coincident pair, not just one at 90 degrees. So you are still using XY when you do 120-coincident-cardioids. (And "AB" refers to a spaced pair, so far as I know.)


There seems an awful lot of confusion about terminology. While we're on it, let me mention a really important error: People use the word "coincident" for arrays that are not coincident! This really matters, folks! "Coincident" means exactly, precisely coin
cident. Now of course that can only apply to Lateral coincidence; the mikes will still be spaced vertically, because mikes cannot occupy the same physical spot. But yes, it really does matter, and we made the demo recording which proved it.


Coincident means that a straight line lying IN (not on) the exact middle of the upper diaphragm extends to lie in the exact middle of the lower diaphragm. None of this business of 1" spacing.


If you want to space the mikes because it sounds better to you, more power to you! You probably know more about it than I do! But please please Don't Call This "Coincident"! It just gets everyone confused. And--once again--yes, it does make a difference!


James Boyk

[David Satz]

Scott Dorsey wrote:

> The way I figure it is that if Schoeps can't make a good small diaphragm
> figure-8 at THEIR price point, how can we expect Rode to do so?

??! The Schoeps figure-8 is a wonderful sounding microphone. If I were to
contribute a track to an RAP compilation based on anything I've recorded in
the past few years, it would almost certainly be something I recorded with
a pair of Schoeps figure-8s (probably piano and voice). Those are the
recordings I've been the happiest about during that time.

They don't have as strong a low-frequency response as I would prefer for
some situations, but since their rolloff is at exactly 6 dB/octave, it's
not hard to compensate with careful equalization if desired.

And of course figure-8s can't be used in all recording situations, but
you knew that.

[Arny Krueger]

"James Boyk" <boyk@caltech.edu> wrote in message
news:bi80am$118$1@naig.caltech.edu

> Well, I don't know how to answer. You cannot judge the matter by
> looking at two 3-digit numbers and saying Gee, they're not so very
> different from each other. You can judge only by listening. The
> question was whether 90-coincident-cardioids image correctly. They
> don't; they don't come close.

Isn't "image correctly" a very ill-defined criteria?

[ScotFraser]

<< If you want to space the mikes because it sounds better to you, more power
to you! You probably know more about it than I do! But please please Don't Call
This "Coincident"! >>

I've always called this "almost XY" when I've moved the capsules anywhere away
from truly coincident to about halfway towards ORTF.


Scott Fraser

[ScotFraser]

<< In a concert hall, a stereo mike basically gives more limitations for more
money without any real advantages over a stereo pair. >>

That's for sure. I think the Schoeps ORTF unit costs about twice as much as
accomplishing the same thing with a pair of CMC6's & only has one possible
spacing.


Scott Fraser

[Jerry Steiger]

"James Boyk" <boyk@caltech.edu> wrote in message
news:bi80am$118$1@naig.caltech.edu...
> Well, I don't know how to answer. You cannot judge the matter by looking
at two 3-digit numbers and saying Gee, they're not so very different from
each other. You can judge only by listening.
Snip
>but facts are facts; and the fact is that 90-coincident-cardioids don't
work well in theory or in practice.

James,

Those two statements seem to be contradictory. If it's a listening judgment
it's an opinion, not a fact.

Jerry Steiger

[James Boyk]

Jerry Steiger wrote: > ...If it's a listening judgment it's an opinion, not a fact.

Sorry, I disagree.

James Boyk

[Roger W. Norman]

Shouldn't have used the word "require", and of course you are correct. I
generally try to keep it within the range of reasonable purchases of which
you will find, in almost all circumstances, a dual diaphram. I'm too stupid
to see how a single diaphram mic is going to have a charged backplate and
have reasonable sound coming in from the back of the 8. Maybe one of these
days.

And yes, in particular a wide pair of cardiods will indeed have a wider
stereo field than a narrow cardioid in the same application. I'm used to
KM140s, KM184s and other pencil mics to do such miking, and of those I seem
to lean towards my stupid little Marshall 603s in that configuration and get
excellent spread on a Steinway, and in jazz, a majority of the piano
player's time is spent in the middle of the range. But I wouldn't
necessarily stick them up for room recording, which Blumlein seems to be
designed for. And in the case of figure of 8s, it seems they are a little
more narrow than cardioids that I have, however I don't work with the best
mics in the world. Thusly my limited knowledge and experience suggest that I
wouldn't use a coincident pair of cardioids for the purpose or room miking.
I would obviously have to make that type of choice, however, from being at
the room because circumstances dictate more about what you're going to use
than the theory or the functional aspects of different types of mics. Don't
get me wrong. I do planning and diagram stage setups out for every show I
do, but an unknown room isn't so easily planned for.

But at least I believe I specified that I was using the 90 degree crossed
cardioids in a close miking situation, and I somehow doubt that I'd use
figure of 8s in close miking a piano.

As always, David, it sure is nice to have your input on this board,
especially regarding mics and their application.

--


Roger W. Norman
SirMusic Studio
Purchase your copy of the Fifth of RAP CD set at www.recaudiopro.net.
See how far $20 really goes.




"David Satz" <DSatz@msn.com> wrote in message
news:e6a68193.0308230613.439979a9@posting.google.c om...
> Roger Norman wrote:
>
> > Figure of 8 mics require dual capsules [ ... ]
>
> That's simply not true. A dual-capsule design such as the Neumann KM 86,
> or a dual-diaphragm design as in the Neumann KM 56 or KM 88, is certainly
> possible--but so is a capsule design with a single diaphragm exposed on
> both sides symmetrically, as the Schoeps MK 8 and Neumann AK 120.
>
>
> > [ ... ] which in a small condenser, is pretty hard to make.
>
> Well, it is pretty hard to make good microphones of any kind! But the
> examples I gave above are all small condensers that are well known and
> successfully used as bidirectional microphones over many years.
>
>
> > And they aren't in a front facing configuration, which is about the
> > only thing a small condenser will allow.
>
> The situation with small and large condensers is exactly the same in
> this respect.
>
> One important use of figure-8 microphones is as the "S" microphone in
> an M/S pair. In that application you aim the null plane of the figure-8
> forward toward the center of the sound source. Directional patterns are
> three-dimensional, so for M/S you can aim the tip of the microphone
> directly at the center of the sound source if that's more convenient.
>
>
> > I don't see a problem with coincident mics at 90 degrees. I use this
> > configuration often [ ... ]
>
> I've noticed that your whole discussion omits any consideration of the
> directional pattern of the microphones you're using. But that's the
> real issue here--the stereo image depends not just on the angle between
> a coincident pair, but also on the directional pattern of the mikes.
>
> This thread began with a discussion of crossed cardioids. A cardioid
> is a blend of pressure and pressure-gradient response in a 50/50 mixture.
> The pressure response is essentially omnidirectional (i.e. except at high
> frequencies). Thus two coincident cardioids at _any_ included angle will
> put out 50% the identical signal, due to their 50% pressure response.
>
> Michael Williams has published a set of curves which show the spatial
> distribution of apparent sound sources when they've been recorded with
> various coincident and non-coincident microphone pairs and played back
> on loudspeakers. What Prof. Boyk has said in this thread is precisely
> supported by the Williams curves: with 90-degree coincident cardioids,
> too much of the sound "bunches up" in the apparent center of the image.
> That is only to be expected given the "nearly mono" nature of the pickup.

[Roger W. Norman]

I noticed that this is based on the design of Michael Gerzon, so I assume
that it does what it's supposed to do.

--


Roger W. Norman
SirMusic Studio
Purchase your copy of the Fifth of RAP CD set at www.recaudiopro.net.
See how far $20 really goes.




"Bob Cain" <arcane@arcanemethods.com> wrote in message
news:3F45CC98.A05ED80D@arcanemethods.com...
>
>
> James Boyk wrote:
> >
> > The odd thing is that Blumlein showed how to use spaced omni's with a
"Blumlein shuffler" to get correct stereo; and this technique offers
remarkable power & flexibility; yet despite all the people who like to use
spaced omni's, the shuffler doesn't exist commercially. There are things
called shufflers, but they're not the Blumlein shuffler.
> >
> > James Boyk
>
> The Waves S1 Stereo Imager plugin claims to implement true
> Blumlein shuffling. See:
>
> http://www.waves.com/htmls/prods/indi/s1.html
>
>
>
> Bob
> --
>
> "Things should be described as simply as possible, but no
> simpler."
>
> A. Einstein

[Roger W. Norman]

I'd have to suggest that, in application, it's the application itself that
specifies whether it works or not. But, again, I'm talking about an
application whereby my results are from a closely mic'd piano with 90 degree
cardioids, not a room where an orchestra is playing. In a more ambient
situation with acoustic instruments I'd be more likely to simply mic a piano
outside of the shell in mono because other than the piano player, the
instrument is really only heard in mono, although if it's in a really nice
hall I'd go for the Blumlein. Again, application specifies the use. I'd be
more than willing to agree that a 90 degree cardioid setup would not be what
I'd use for a room recording, no matter where I could put the mics. I
believe your experience probably represents more along the area of classical
recordings in decent rooms, judging from your bona fides. On the other
hand, I'm doing big bands and small jazz combos and sometimes 12 or more of
them mixed and matched throughout a day. Room recordings aren't a
consideration, so techniques that you and most would use possibly don't
really apply. I like having room mics when possible, but they are going to
be hanging from some lighting rig out of the way of the crowd, and certainly
conceivably not in the most correct position for such work. I don't get the
big jobs where I'm in a 3,000 sq ft live room of a studio.

Didn't you use to have a website listed on your signature James? If you've
got one, I'd like to visit it. Perhaps you have some of your demo stuff
available?

--


Roger W. Norman
SirMusic Studio
Purchase your copy of the Fifth of RAP CD set at www.recaudiopro.net.
See how far $20 really goes.




"James Boyk" <boyk@caltech.edu> wrote in message
news:bi80am$118$1@naig.caltech.edu...
> Well, I don't know how to answer. You cannot judge the matter by looking
at two 3-digit numbers and saying Gee, they're not so very different from
each other. You can judge only by listening. The question was whether
90-coincident-cardioids image correctly. They don't; they don't come close.
I suggest that the virtues of the best stereo arrays, and the defects of
others, will become more vivid to you if you listen to our demo recording.
It's your privilege not to care about imaging---though personally I think
it's of fundamental importance to successful recording, for a reason I
haven't gone into here---but facts are facts; and the fact is that
90-coincident-cardioids don't work well in theory or in practice.
>
> James Boyk
>

[Sugarite]

> Somone mentioned a new stereo mike that embodies coincident cardioids
crossed at 90 degrees. I find it odd to use this arrangement, since the
stereo given by this arrangement is much too narrow, and is also irregular
in movement across the stage. This has been noted by others in the group in
other contexts, and is also shown in the stereo miking demo recording made
in my lab.
>
> On the other hand, what should the mike be instead? If it were
ORTF--arguably the best you can do if you're confined to cardioids--it would
be physically more awkward, and probably more vulnerable to damage. But
perhaps 120 degrees would have been usefully better. As long as they were at
it, though, why not make a coincident, 90-degree pair of
condenser....figure-8's? Even go all the way and make single-diaphragm
fig-8's, like the Schoeps MK-8.

I own a Rode NT4 (which is a coincident cardioid XY small diaphram pair like
you describe) and use it often for stereo location recordings. Serveral
issues haven't been addressed in all the other replies in this thread, so I
figured I'd start from the top:

Firstly, post processing is always required to tame a location recording to
be even remotely realistic. The widening of a 90 degree cardioid XY pair is
just one of many processes that must be done, and even though another mic
format might be better suited to rendering more natural imaging before post,
it's a minor issue compared to other factors, one of which is proper
rejection. I don't claim to know exactly why 90 degree coincident cardioids
can offer the best imaging, but I'm going to offer a plausible explanation
for the specific circumstances of a live concert, which can also apply to
other environments.

Most PA speakers at music venues are mounted parallel to each other, so the
mic has to be towards the rear of the room to get decent direct sound from
the horns especially. The rejection pattern of the cardioid XY is such that
when the stereo image is widened during post, the resulting rear information
becomes an amalgomation of what was originally mostly side information, so
the perceived position of the listener is a lot closer than the mic actually
was. It's the best of both worlds - the balanced mix, ambience, and
frequency response of a mid-rear location combined with the scope, impact,
and potency of the front row.

Here's an example of this technique:
http://www.thetrewsmusic.com/media/mp3/060703-tow.zip
The mic was actually about 50' back from the stage in one of my favorite
recording venues (Kee to Bala, Muskoka region, Ontario, Canada), and yeah
it's rather squashed to let the room ambience add some hugeness too it, it's
a promotional clip on the band's website...

It is NOT the same as placing the mic closer and using a wider differential
angle. If the mic were as close as it seems, it would not have had the
clarity or balance that can only be found within the good dispersion area of
the PA speakers. A wider differential angle would not allow for as much
perceived proximity improvement, and a narrower angle wouldn't offer enough
side info to work with. A pair of omni's would render a big pile of mud by
comparison, and figure-8's would slew the rear imaging and leave a gap up
front. AFAIK the cardioid XY pattern is the only way to acheive this
effectively, probably because the 90 degree angle represents the separation
between the two independent component vectors of the forces imposed on a
single positon in two dimensions, hence the term "XY", much like the grooves
on stereo LP's. I haven't done enough recording of acoustic performances to
comment concisely, but there are again advantages to a rear mic placement
with widening during post, and so far that process hasn't failed me.

I also strongly discourage using separated mics for the differential delay
imposed. I've heard the argument to death that it makes sense because our
ears are separated and the human auditory system depends on differential
delay for imaging, but we're recording for a stereo, not a human auditory
system. AFAIK nobody makes a CD player that plugs directly into the
cerebral cortex. A stereo and the listener's ears do their part on their
own and I see no reason to make special accommodations for this particular
aspect. Coincident mics pick up the stereo image found at one position,
then a properly configured stereo allows the listener to assume that
positon. It is impossible for a listener to be in two positions, and also
impossible for a stereo to reproduce two postions, so having mics in
different positions generally makes about as much sense as putting legs on a
car.

[James Boyk]

Sugarite wrote: Firstly, post processing is always required to tame a location
recording to be even remotely realistic.


You must work in an entirely different genre from anything I've experienced. Granted, I do only a very limited kind of thing; but it involves *avoiding* all unnecessary processing and for that matter all unnecessary gain stages, to keep the sound as pure a
s possible.



> ...The widening of a 90 degree cardioid XY pair is just one of many processes that must be done,

You convert XY to MS, increas the proportion of S, then convert back to XY?



> ...and even though another mic
> format might be better suited to rendering more natural imaging before post,
> it's a minor issue compared to other factors, one of which is proper
> rejection. I don't claim to know exactly why 90 degree coincident cardioids
> can offer the best imaging, but I'm going to offer a plausible explanation
> for the specific circumstances of a live concert, which can also apply to
> other environments.

Live rock concert, that is.



> Most PA speakers at music venues are mounted parallel to each other, so the
> mic has to be towards the rear of the room to get decent direct sound from
> the horns especially. The rejection pattern of the cardioid XY is such that
> when the stereo image is widened during post, the resulting rear information
> becomes an amalgomation of what was originally mostly side information, so
> the perceived position of the listener is a lot closer than the mic actually
> was. It's the best of both worlds - the balanced mix, ambience, and
> frequency response of a mid-rear location combined with the scope, impact,
> and potency of the front row.

I'd love to hear "before" and "after" examples.



> Here's an example of this technique: http://www.thetrewsmusic.com/media/mp3/060703-tow.zip

Can you put this on a web site instead?



> The mic was actually about 50' back from the stage in one of my favorite
> recording venues (Kee to Bala, Muskoka region, Ontario, Canada), and yeah
> it's rather squashed to let the room ambience add some hugeness too it, it's
> a promotional clip on the band's website...

> It is NOT the same as placing the mic closer and using a wider differential
> angle. If the mic were as close as it seems, it would not have had the
> clarity or balance that can only be found within the good dispersion area of
> the PA speakers. A wider differential angle would not allow for as much
> perceived proximity improvement, and a narrower angle wouldn't offer enough
> side info to work with. A pair of omni's would render a big pile of mud by
> comparison, and figure-8's would slew the rear imaging and leave a gap up
> front.

I don't get this statement about fig-8's.



> ...AFAIK the cardioid XY pattern is the only way to acheive this
> effectively, probably because the 90 degree angle represents the separation
> between the two independent component vectors of the forces imposed on a
> single positon in two dimensions, hence the term "XY", much like the grooves
> on stereo LP's....


I can't follow this.



> I also strongly discourage using separated mics for the differential delay
> imposed. I've heard the argument to death that it makes sense because our
> ears are separated and the human auditory system depends on differential
> delay for imaging, but we're recording for a stereo, not a human auditory
> system.


Huh? A "stereo" listens to your recordings? No, a human listens. We certainly are ALWAYS recording for a human auditory system. And Blumlein showed why the right way to do that is to use coincident fig-8's (or spaced omnis with the "Blumlein shuffler," whi
ch no one seems to use).



> ...AFAIK nobody makes a CD player that plugs directly into the
> cerebral cortex. A stereo and the listener's ears do their part on their
> own and I see no reason to make special accommodations for this particular
> aspect. Coincident mics pick up the stereo image found at one position,
> then a properly configured stereo allows the listener to assume that
> positon. It is impossible for a listener to be in two positions, and also
> impossible for a stereo to reproduce two postions, so having mics in
> different positions generally makes about as much sense as putting legs on a
> car.

Well, forgive me, but this is a psychoacoustically naive point of view. Can't it be enough just to say, "Coincident works for me"? There's no need to argue deep perceptual issues.


James Boyk

[Bob Cain]

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William Sommerwerck wrote:
>
> > I think this is beside the point in any event. For any kind
> > of real listening environment we don't yet know how to
> > record something and reproduce it "correctly" in space
> > as all the discussion on the surrsound mailing list will
> > clearly attest. I don't think it is possible, frankly, and
> > think most of the stuff going on is smoke and mirrors
> > with a lot of persuasive heuristics used to try and justify
> > the "correctness" of each proposed method.
>
> No offense, but you've obviously never heard Ambisonic recordings. I've actually
> made them, and the sound is much closer to what you hear live than any other
> speaker-based surround system.

None taken, but I have. I very much like the illusion that
is created but I understand the fundamental theory well
enough to know exactly what can and can't be accomplished
with a first order recording. Even in an anechoic situation
with very sophisticated reconstruction methods the best that
can be accomplished is to recreate at one point in space the
acoustic field that was measured by the mic. In theory, at
that one point, the exact time varying sound velocity vector
and pressure scalar that existed where the recording was
taken can be recreated but at no surrounding point can
anything be stated relative to the original sound field in
which the measurement (recording) was taken.

In practice, after considering the high frequency
limitations of the Ambisonic method of measurement, due to
its lack of true coincidence and the less than ideal nature
of the microphones, as well as putting that ideal
reconstruction system in a room with a head at the
reconstruction point that is attached to a body seated in
furniture and _all_ bets are off.

This is not to say that Ambisonics doesn't go a long way to
creating an illusion that is _very_ satisfying but one can
simply not say that it is an accurate recreation at the
listener's ears of the event that was recorded.


Bob
--

"Things should be described as simply as possible, but no
simpler."

A. Einstein

[Bob Cain]

James Boyk wrote:
>
> > ...AFAIK the cardioid XY pattern is the only way to acheive this
> > effectively, probably because the 90 degree angle represents the separation
> > between the two independent component vectors of the forces imposed on a
> > single positon in two dimensions, hence the term "XY", much like the grooves
> > on stereo LP's....
>
> I can't follow this.

It measures the vector velocity component of the acoustic
field, the pressure gradient, in an orthogonal fashion.
It's why the Blumlein is at 90 degrees and the same
reasoning applies to the crossed cardiods which each contain
the sum of a scalar pressure component and vector pressure
gradient component.


Bob
--

"Things should be described as simply as possible, but no
simpler."

A. Einstein

[Justin Ulysses Morse]

James Boyk <boyk@caltech.edu> wrote:

> That was my point. No reason the NT4 couldn't have been fig-8's.


I don't think the NT4's intended market would understand the advantages
of a fig-8 over a cardioid. Nor would they understand the advantages
of 130 degrees over 90 degrees. To the lay person (which includes 95%
of the recording gear market), it seems counter-intuitive to use
microphones that pick up sound coming from the opposite direction, or
to point the microphones someplace other than essentially toward the
musical source they're trying to record. People who understand the
geometry of microphone pickup patterns are looking into other brands
and models of microphone.

ulysses

[James Boyk]

Bob Cain wrote:
> It measures the vector velocity component of the acoustic
> field, the pressure gradient, in an orthogonal fashion.
> It's why the Blumlein is at 90 degrees and the same
> reasoning applies to the crossed cardiods which each contain
> the sum of a scalar pressure component and vector pressure
> gradient component.

Sure. But the cardioid embodies the *wrong* sum!

jb

[Chris Hornbeck]

On Sat, 23 Aug 2003 15:05:27 -0400, "Roger W. Norman"
<rnorman@starpower.net> wrote:

> how a single diaphram mic is going to have a charged backplate and
>have reasonable sound coming in from the back of the 8.

I've never seen one, but imagine the construction to be
like a really, really small electrostatic speaker, with
porous fixed plates and a charged diaphram between.

A side benefit, if the charge is constant, is an inherent
linearity missing from conventional single-ended mics.

Chris Hornbeck
http://www.votetoimpeach.org/

[Arny Krueger]

"James Boyk" <boyk@caltech.edu> wrote in message
news:bi8chu$502$1@naig.caltech.edu
> Jerry Steiger wrote: > ...If it's a listening judgment it's an
> opinion, not a fact.
>
> Sorry, I disagree.

And that's just an opinion, too.

[Arny Krueger]

"Roger W. Norman" <rnorman@starpower.net> wrote in message
news:bi8eru$r88$1@bob.news.rcn.net

> I'd have to suggest that, in application, it's the application itself
> that specifies whether it works or not.

Closer...

I think we can all agree that is the comparison of actual results to
*someone's* expectations that determines whether something *works* or not.

[William Sommerwerck]

> This is not to say that Ambisonics doesn't go a long way to
> creating an illusion that is _very_ satisfying but one can
> simply not say that it is an accurate recreation at the
> listener's ears of the event that was recorded.

Like many people, you're criticizing Ambisonics for the wrong reasons. I
interpret this as a perverse excuse for rejecting something that happens to work
extremely well. And it IS perverse to deny a system that actually takes into
account how the ears and brain interpret directionality.

Ambisonic playback comes very close to sounding as if you are actually sitting
at the mic position. I have never heard any other form of recording and playback
(except, of course, for binaural) that comes even remotely close. Had Ambisonics
been widely accepted as a standard recording format, it could have been
rationally enhanced with HRTF and similar features.

No one is obliged to use the SoundField mic. My recordings were made with Pearl
TC-4v mics, and Nimbus has used Schoeps capsules for many years.

[Chris Hornbeck]

On Sat, 23 Aug 2003 10:33:13 -0700, "Jerry Steiger"
<gwsteiger@comcast.net> wrote:

> If it's a listening judgment
>it's an opinion, not a fact.

"Truth is stranger than fact."
Grandpa Jones


Chris Hornbeck
http://www.votetoimpeach.org/

[Bob Cain]

William Sommerwerck wrote:
>
> > This is not to say that Ambisonics doesn't go a long way to
> > creating an illusion that is _very_ satisfying but one can
> > simply not say that it is an accurate recreation at the
> > listener's ears of the event that was recorded.
>
> Like many people, you're criticizing Ambisonics for the wrong reasons. I
> interpret this as a perverse excuse for rejecting something that happens to work
> extremely well. And it IS perverse to deny a system that actually takes into
> account how the ears and brain interpret directionality.

Then you've interpreted me incorrectly. I loved the sound
of Ambisonics at the single demo I heard (at that time I
didn't understand enough about it to even note the speaker
configuration used for reproduction much less ask about the
feed transformations) but I don't like the extravagant
claims made for its "correctness" now that I fully
understand the theory and practice. I don't think that
theoretical correctness is necessasary for a system to do a
damn nice job of capturing something that, when carefully
reproduced, is very pleasant and plausible. Yes, it does
take the factors you mention into account and can present
enough of a semblance of that information so that the
ear/brain finds it most interesting and is generally willing
to suspend disbelief enough to thoroughly enjoy the
resemblance.

FWIW, I liked it enough that I am in process (paused,
actually) of constructing a low cost tetrahedral cardiod
array and developing sophisticated host DSP transformations
based on empirical measurement to see if I can come up with
something that mere people can afford. I think that with
the DSP assist it can be brought much closer to Gerzon's
ideal than has been achieved to date and with a much less
expensive array.


Bob
--

"Things should be described as simply as possible, but no
simpler."

A. Einstein

[William Sommerwerck]

I need to correct what is perhaps the biggest misunderstanding about Ambisonics.

For some inexplicable reason, most of the people who criticize Ambisonics state
that Ambisonics claims to reproduce the original waveform over a large listening
area, then (correctly) point out that this is not possible.

I've read a lot of Ambisonic literature (theoretical and otherwise), and I have
never seen anything even remotely approaching this claim. What actually happens
(and what I think people are misinterpreting) is that you can walk all around
the listening room without losing the image -- something that conventional
stereo recording cannot come close to doing.

I applaud your efforts to come up with a less-expensive and better-quality
SoundField array. (I own a SoundField mic, and am not really happy with the
sound quality, which is a bit dark and grundgy.) However, the problem isn't its
cost, but the violently _negative_ way most engineers view any attempt to
accurately record sound. If this were possible, they'd be out of job.


>> Like many people, you're criticizing Ambisonics for the wrong
>> reasons. I interpret this as a perverse excuse for rejecting
>> something that happens to work extremely well. And it IS
>> perverse to deny a system that actually takes into account
>> how the ears and brain interpret directionality.

> Then you've interpreted me incorrectly. I loved the sound
> of Ambisonics at the single demo I heard (at that time I
> didn't understand enough about it to even note the speaker
> configuration used for reproduction much less ask about the
> feed transformations) but I don't like the extravagant
> claims made for its "correctness" now that I fully
> understand the theory and practice. I don't think that
> theoretical correctness is necessasary for a system to do a
> damn nice job of capturing something that, when carefully
> reproduced, is very pleasant and plausible. Yes, it does
> take the factors you mention into account and can present
> enough of a semblance of that information so that the
> ear/brain finds it most interesting and is generally willing
> to suspend disbelief enough to thoroughly enjoy the
> resemblance.

> FWIW, I liked it enough that I am in process (paused,
> actually) of constructing a low cost tetrahedral cardiod
> array and developing sophisticated host DSP transformations
> based on empirical measurement to see if I can come up with
> something that mere people can afford. I think that with
> the DSP assist it can be brought much closer to Gerzon's
> ideal than has been achieved to date and with a much less
> expensive array.\

[Roger W. Norman]

See, it's good to be stupid. Get's one some answers! <g>

--


Roger W. Norman
SirMusic Studio
Purchase your copy of the Fifth of RAP CD set at www.recaudiopro.net.
See how far $20 really goes.




"Chris Hornbeck" <guyville@removethisaristotle.net> wrote in message
news:eevfkvkl5qmjgmf15c1qandpqtes6lnsej@4ax.com...
> On Sat, 23 Aug 2003 15:05:27 -0400, "Roger W. Norman"
> <rnorman@starpower.net> wrote:
>
> > how a single diaphram mic is going to have a charged backplate and
> >have reasonable sound coming in from the back of the 8.
>
> I've never seen one, but imagine the construction to be
> like a really, really small electrostatic speaker, with
> porous fixed plates and a charged diaphram between.
>
> A side benefit, if the charge is constant, is an inherent
> linearity missing from conventional single-ended mics.
>
> Chris Hornbeck
> http://www.votetoimpeach.org/
>

[ScotFraser]

<< Firstly, post processing is always required to tame a location recording to
be even remotely realistic.

Post processing is never necessary if the initial recording was done correctly.

<<Most PA speakers at music venues are mounted parallel to each other, so the
mic has to be towards the rear of the room to get decent direct sound from
the horns especially.>>

If this is indeed the case you are dealing with an improperly set up sound
system. While this is very likely true in many venues, I wouldn't base a theory
around bad sound system design.
Scott Fraser

[ScotFraser]

<< I applaud your efforts to come up with a less-expensive and better-quality
SoundField array. (I own a SoundField mic, and am not really happy with the
sound quality, which is a bit dark and grundgy.)>>

Why not upgrade the existing hardware. It couldn't too difficult to redesign
the capsule electronics, & even replace diaphragms if needed to get the color
you desire out of the system. Or do you suspect the darkness & grunge comes
from the processor? Certainly the analog path there could be brought up to
current standards.

<< However, the problem isn't its
cost, but the violently _negative_ way most engineers view any attempt to
accurately record sound. >>

All engineers are attempting to (more or less) accurately record sound. I think
you extrapolate motives a bit much here.

<<If this were possible, they'd be out of a job. >>

No, because intentional inaccuracies, such as are brought out by close miking,
will always be a major part of the art of recording.




Scott Fraser

[James Boyk]

Roger W. Norman wrote: Didn't you use to have a website listed on your
signature James? If you've got one, I'd like to visit it. Perhaps
you have some of your demo stuff available?


Tnx for your interest. I have three websites. Each is fairly extensive.

http://www.cco.caltech.edu/~boyk
http://www.cco.caltech.edu/~musiclab
http://www.performancerecordings.com

James Boyk

[Roger W. Norman]

Thanks. I think I've visited them before, but I'm going to look again.

--


Roger W. Norman
SirMusic Studio
Purchase your copy of the Fifth of RAP CD set at www.recaudiopro.net.
See how far $20 really goes.




"James Boyk" <boyk@caltech.edu> wrote in message
news:bib0ii$sa2$1@naig.caltech.edu...
> Roger W. Norman wrote: Didn't you use to have a website listed on your
> signature James? If you've got one, I'd like to visit it. Perhaps
> you have some of your demo stuff available?
>
>
> Tnx for your interest. I have three websites. Each is fairly extensive.
>
> http://www.cco.caltech.edu/~boyk
> http://www.cco.caltech.edu/~musiclab
> http://www.performancerecordings.com
>
> James Boyk
>

[Roger W. Norman]

On a personal note, I'd never try to record any music based on the PA
speakers being a part of the recording. In my opinion, and I run live sound
systems, the SR is never as good as the live music from the musicians. If
you're that far back and getting SR in the recording you need to move up.
James' speciality is live acoustic sound in world class venues that don't
have SR. Mine is live from the stage. If your's is live in the room from
SR speakers then I don't believe it matters all that much how you set the
mics.

Sorry, not trying to rag on you. Just not the same thing we're talking
about. The concept is to be the listener as in someone that can actually
hear the performance from the stage. Unless I'm getting your post wrong,
which certainly has been known to happen.

--


Roger W. Norman
SirMusic Studio
Purchase your copy of the Fifth of RAP CD set at www.recaudiopro.net.
See how far $20 really goes.




"Sugarite" <nobody@home.com> wrote in message
news:MOP1b.7353$q9.450820@read1.cgocable.net...
> > Somone mentioned a new stereo mike that embodies coincident cardioids
> crossed at 90 degrees. I find it odd to use this arrangement, since the
> stereo given by this arrangement is much too narrow, and is also irregular
> in movement across the stage. This has been noted by others in the group
in
> other contexts, and is also shown in the stereo miking demo recording made
> in my lab.
> >
> > On the other hand, what should the mike be instead? If it were
> ORTF--arguably the best you can do if you're confined to cardioids--it
would
> be physically more awkward, and probably more vulnerable to damage. But
> perhaps 120 degrees would have been usefully better. As long as they were
at
> it, though, why not make a coincident, 90-degree pair of
> condenser....figure-8's? Even go all the way and make single-diaphragm
> fig-8's, like the Schoeps MK-8.
>
> I own a Rode NT4 (which is a coincident cardioid XY small diaphram pair
like
> you describe) and use it often for stereo location recordings. Serveral
> issues haven't been addressed in all the other replies in this thread, so
I
> figured I'd start from the top:
>
> Firstly, post processing is always required to tame a location recording
to
> be even remotely realistic. The widening of a 90 degree cardioid XY pair
is
> just one of many processes that must be done, and even though another mic
> format might be better suited to rendering more natural imaging before
post,
> it's a minor issue compared to other factors, one of which is proper
> rejection. I don't claim to know exactly why 90 degree coincident
cardioids
> can offer the best imaging, but I'm going to offer a plausible explanation
> for the specific circumstances of a live concert, which can also apply to
> other environments.
>
> Most PA speakers at music venues are mounted parallel to each other, so
the
> mic has to be towards the rear of the room to get decent direct sound from
> the horns especially. The rejection pattern of the cardioid XY is such
that
> when the stereo image is widened during post, the resulting rear
information
> becomes an amalgomation of what was originally mostly side information, so
> the perceived position of the listener is a lot closer than the mic
actually
> was. It's the best of both worlds - the balanced mix, ambience, and
> frequency response of a mid-rear location combined with the scope, impact,
> and potency of the front row.
>
> Here's an example of this technique:
> http://www.thetrewsmusic.com/media/mp3/060703-tow.zip
> The mic was actually about 50' back from the stage in one of my favorite
> recording venues (Kee to Bala, Muskoka region, Ontario, Canada), and yeah
> it's rather squashed to let the room ambience add some hugeness too it,
it's
> a promotional clip on the band's website...
>
> It is NOT the same as placing the mic closer and using a wider
differential
> angle. If the mic were as close as it seems, it would not have had the
> clarity or balance that can only be found within the good dispersion area
of
> the PA speakers. A wider differential angle would not allow for as much
> perceived proximity improvement, and a narrower angle wouldn't offer
enough
> side info to work with. A pair of omni's would render a big pile of mud
by
> comparison, and figure-8's would slew the rear imaging and leave a gap up
> front. AFAIK the cardioid XY pattern is the only way to acheive this
> effectively, probably because the 90 degree angle represents the
separation
> between the two independent component vectors of the forces imposed on a
> single positon in two dimensions, hence the term "XY", much like the
grooves
> on stereo LP's. I haven't done enough recording of acoustic performances
to
> comment concisely, but there are again advantages to a rear mic placement
> with widening during post, and so far that process hasn't failed me.
>
> I also strongly discourage using separated mics for the differential delay
> imposed. I've heard the argument to death that it makes sense because our
> ears are separated and the human auditory system depends on differential
> delay for imaging, but we're recording for a stereo, not a human auditory
> system. AFAIK nobody makes a CD player that plugs directly into the
> cerebral cortex. A stereo and the listener's ears do their part on their
> own and I see no reason to make special accommodations for this particular
> aspect. Coincident mics pick up the stereo image found at one position,
> then a properly configured stereo allows the listener to assume that
> positon. It is impossible for a listener to be in two positions, and also
> impossible for a stereo to reproduce two postions, so having mics in
> different positions generally makes about as much sense as putting legs on
a
> car.
>
>

[Sugarite]

> Sugarite wrote: Firstly, post processing is always required to tame a
location
> recording to be even remotely realistic.
>
> You must work in an entirely different genre from anything I've
experienced. Granted, I do only a very limited kind of thing; but it
involves *avoiding* all unnecessary processing and for that matter all
unnecessary gain stages, to keep the sound as pure as possible.

Yeah, I work in pro audio, not sure what you work in. It doesn't take Ben
Hogan to illustrate how the process of sound reproduction is a very
unnatural act, and therefore will require invasive procedures in order to
seem natural. (Ben said the same thing of a golf swing and his book is
pretty much a bible to pro golfers) For example, the use of microphones and
speakers by their very nature is expansive, so by doing nothing you're
actually in effect applying an expander. The signal is "pure" but the sound
has been significantly altered. And if you think the human auditory system
involves no significant processing by the brain, think again. (pardon the
pun)

> > ...The widening of a 90 degree cardioid XY pair is just one of many
processes that must be done,
>
> You convert XY to MS, increas the proportion of S, then convert back to
XY?

Actually I use Waves Stereo Imager, which does what I need in the digital
domain, presumably by that process. I know what you're going to say next, I
should avoid the extra process and record in MS. I don't like the idea of a
side channel running through any analog gear for fear that some expansion or
compression might occur disproportionate to the mono channel, which can
really warp the stereo image. That's what generally happens if you record
MS with a tube preamp, the saturation effect makes the middle wider and
brings the sides in. Any dynamics manipulation applied to MS must be keyed
by the sum signal, which is impossible to do with any colored dual preamp.
I prefer using a tube preamp in XY at the cost of the extremely minor extra
process.

> > ...and even though another mic
> > format might be better suited to rendering more natural imaging before
post,
> > it's a minor issue compared to other factors, one of which is proper
> > rejection. I don't claim to know exactly why 90 degree coincident
cardioids
> > can offer the best imaging, but I'm going to offer a plausible
explanation
> > for the specific circumstances of a live concert, which can also apply
to
> > other environments.
>
> Live rock concert, that is.

Anything with sound reinforcement actually, so virtually any performance
before a significant audience

> I'd love to hear "before" and "after" examples.

I think I've done enough already.

> > Here's an example of this technique:
http://www.thetrewsmusic.com/media/mp3/060703-tow.zip
>
> Can you put this on a web site instead?

Uh, that is a website (http). Sorry it's in zip format (expands to an mp3),
not sure what the webmaster is thinking there.

> > ...figure-8's would slew the rear imaging and leave a gap up front.
>
> I don't get this statement about fig-8's.

Well that process wouldn't be applied to fig-8's anyways, don't worry about
it.

> > ...AFAIK the cardioid XY pattern is the only way to acheive this
> > effectively, probably because the 90 degree angle represents the
separation
> > between the two independent component vectors of the forces imposed on a
> > single positon in two dimensions, hence the term "XY", much like the
grooves
> > on stereo LP's....
>
> I can't follow this.

It's pretty basic physics, do a websearch on "component vectors" and you'll
probably see some diagrams, it's also important to sailing theory.

> Huh? A "stereo" listens to your recordings? No, a human listens. We
certainly are ALWAYS recording for a human auditory system.

Yes, a stereo listens, that's exactly what I said, word for word...
</sarcasm>

I was illustrating how our responsibility stops at the CD, so we get paid no
matter what species is placed in front of the speakers. It's really just an
issue of semantics, and just my opinion. Another more important aspect of
what I said is that the human auditory system is not the template by which
all recording devices and techniques should be based. It is an analysis
tool, not a sound reproduction tool, and is the result of the evolution of
our bodies which have many other systems, each comprimised to accommodate
each other for the most effective total package. Microphones are not
snail-shaped, full of liquid, with hairs lining the interior, for example.

Ears actually have thousands of sensors, and it's been theorized that each
covers a very small frequency range, with only marginal overlap. What we
hear might actually be a tone generator in our brain that is triggered by
those sensors like a keyboard, except with proper phase information. You
want to try emulating that? That theory would be consistent with what's
known about our vision system, which is a picture generated by the brain
based on the information gathered by the eyes. Science hasn't produced any
reliable explanation to date, so who knows.

> And Blumlein showed why the right way to do that is to use coincident
fig-8's (or spaced omnis with the "Blumlein shuffler," which no one seems to
use).

I never said there was a right or wrong way, in fact I would disagree with
anyone claiming there was a right or wrong way. Different techniques are
used, resulting in different effects. It's the difference between a craft
and a science. The coincident fig-8 format is well-suited to a realistic
representation of an environment which offers a mic position which is *both*
where the best tone and balance between instruments, voices, and ambience
can be found *and* the ideal position to be recreated on a stereo.
Unfortunately, I have *never* encountered such an environment where sound
reinforcement was involved. Every time the sound is better at a significant
distance from the performers, but listeners at home want to feel close to
the action. Just like a macro lens at a distance can make different objects
seem closer to the same distance away from the camera, my way lets you seem
close without the imbalances caused by proportionally greater differences in
proximity. I'm essentially zooming in from afar to help keep certain
aspects from upstaging others.

Actually yeah, that's the ticket right there. I can't explain it any better
than that. If that doesn't convince you of it's potential, then don't
bother trying it, you won't know how to work with it in post.

> > ...AFAIK nobody makes a CD player that plugs directly into the
> > cerebral cortex. A stereo and the listener's ears do their part on their
> > own and I see no reason to make special accommodations for this
particular
> > aspect. Coincident mics pick up the stereo image found at one position,
> > then a properly configured stereo allows the listener to assume that
> > positon. It is impossible for a listener to be in two positions, and
also
> > impossible for a stereo to reproduce two postions, so having mics in
> > different positions generally makes about as much sense as putting legs
on a
> > car.
>
> Well, forgive me, but this is a psychoacoustically naive point of view.
Can't it be enough just to say, "Coincident works for me"? There's no need
to argue deep perceptual issues.

Too late. But I fail to see your point. I've devised a technique from
hundreds of hours of experimentation using scientific principles you
apparently don't comprehend, while you suggest mimicking what happens to be
on our heads and leaving it pretty much as-is. And it's ME that's naive?!
Incompetence I can forgive, but hypocrisy and conceit aren't so easy...

[Justin Ulysses Morse]

Sugarite <nobody@home.com> wrote:

> Yeah, I work in pro audio, not sure what you work in.

ahem.

> Actually I use Waves Stereo Imager, which does what I need in the digital
> domain, presumably by that process. I know what you're going to say next, I
> should avoid the extra process and record in MS. I don't like the idea of a
> side channel running through any analog gear for fear that some expansion or
> compression might occur disproportionate to the mono channel, which can
> really warp the stereo image. That's what generally happens if you record
> MS with a tube preamp, the saturation effect makes the middle wider and
> brings the sides in. Any dynamics manipulation applied to MS must be keyed
> by the sum signal, which is impossible to do with any colored dual preamp.
> I prefer using a tube preamp in XY at the cost of the extremely minor extra
> process.

Right, you wouldn't want to mess up the "imaging" in a recording of a
PA.

> > Live rock concert, that is.
>
> Anything with sound reinforcement actually, so virtually any performance
> before a significant audience

Have you ever been to a real concert? Not one where you sit a quarter
mile away from the band and have the music piped over to you. You
know, a real concert where you sit in a room with some musicians and
hear the sounds coming out of their instruments. You know, a CONCERT?
It could be in a little coffee shop or pub with a jazz trio or a solo
classical guitar, or it could be a huge auditorium with a really loud
fat lady. Or a symphony.

To pretend that you're some excessively qualified authority on live
recording techniques because you have refined your approach to setting
a pair of microphones in front of PA speakers in this forum, where guys
like James Boyk (who knows what live music sounds like) hang out just
makes you sound, well, dumb. Sorry.

Dude, you record PA speakers. Quit giving advice to people who record
instruments.


ulysses

[LeBaron & Alrich]

Sugarite <nobody@home.com> wrote:

> It doesn't take Ben
> Hogan to illustrate how the process of sound reproduction is a very
> unnatural act, and therefore will require invasive procedures in order to
> seem natural.

And some folks make a successful capture that generally obviates
****loads of "necessary" post production. The more natural the music
itself the easier that is. I think Scott Fraser works in por audio, too,
but what do I know.

--
ha

[Sugarite]

> << Firstly, post processing is always required to tame a location
recording to
> be even remotely realistic.
>
> Post processing is never necessary if the initial recording was done
correctly.

Well sure, you could just do the post-processing during the recording, but
why?

I hope you're not implying that a recording done with only a pair of mics
and a neutral preamp would not benefit from further processing. That's just
not how it works.

> <<Most PA speakers at music venues are mounted parallel to each other, so
the
> mic has to be towards the rear of the room to get decent direct sound from
> the horns especially.>>
>
> If this is indeed the case you are dealing with an improperly set up sound
> system. While this is very likely true in many venues, I wouldn't base a
theory
> around bad sound system design.
> Scott Fraser

Another flawed blanket statement. First let's look at the use of the word
"improperly" in the first sentence. PA's are set up to distribute sound to
a mass audience, and generally not to provide an ideal recording
environment, so do you mean that it's improper for recording, or improper in
general?

Either way, I disagree with "bad system design" rendering any theory
invalid. Even if the system is critically flawed, the recording technique
could still demonstrate its effectiveness by rendering a realistic
representation of the flawed system. And if you're going to limit the
venues you record to those without very expansive compression horns and
insufficient or no room tuning (to name a few issues) then you're not going
to do much recording, period.

What I described is only one aspect to my audience recording technique
anyway. There's lots of tricks to deal with sound systems that aren't
condusive to recording. That's where the real fun begins! One room I've
managed to "conquer" has a full twin-turbo-prop airplane suspended from the
ceiling directly between the two main speaker columns, which of course are
mounted in parallel. By isolating one speaker column (it's a mono mix
anyway) from the balcony and pointing the mic in a certain oblique direction
I can get a reasonably balanced audience response and even get some stereo
information from the stage sound. It isn't 100% consistent with the
"actual" sound of the venue, but it's a realistic impression nonetheless.

[ScotFraser]

<< Well sure, you could just do the post-processing during the recording, but
why?>>

Or set up in a way that doesn't require any further signal manipulation to get
what you're after.

<<I hope you're not implying that a recording done with only a pair of mics
and a neutral preamp would not benefit from further processing. That's just
not how it works.>>

I hope you're not implying that it's not possible to record with just a pair of
mics & a neutral preamp with results that need no further processing.

> <<Most PA speakers at music venues are mounted parallel to each other, so
the
> mic has to be towards the rear of the room to get decent direct sound from
> the horns especially.>>
>
> If this is indeed the case you are dealing with an improperly set up sound
> system. While this is very likely true in many venues, I wouldn't base a
theory
> around bad sound system design.

<<Another flawed blanket statement. >>

You should talk.

<< First let's look at the use of the word
"improperly" in the first sentence. PA's are set up to distribute sound to
a mass audience, and generally not to provide an ideal recording
environment, so do you mean that it's improper for recording, or improper in
general?>>

If, as you say, you need to back off into the diffuse field to get a decent
picture of the PA sytem, then the system is improperly setup by virtue of not
providing adequate coverage in the direct field. If your mics are not in the
angle of coverage of the horns in the front half of the room, neither are a lot
of audience members.

<< if you're going to limit the
venues you record to those without very expansive compression horns and
insufficient or no room tuning (to name a few issues) then you're not going
to do much recording, period.>>

Guess it all depends on your clientele. I've heard any number of spectacular
location recordings done by European broadcasters of live concerts I've mixed
FOH. They most definitely don't mic the PA from the back of the hall.

<<What I described is only one aspect to my audience recording technique
anyway. >>

What you described are a bunch of assumptions apparently based on worst case
scenarios, but which are in no way absolutes.




Scott Fraser

[James Boyk]

Sugarite wrote:

> Yeah, I work in pro audio, not sure what you work in.

I've been a member of NARAS in 4 categories, but I guess this doesn't make me a "pro." For credits as performer/engineer/producer for Sheffield Lab and Performance Recordings, see http://www.performancerecordings.com/albums.html . For research/teaching, se
e http://www.its.caltech.edu/~musiclab/ . For writing, see http://www.cco.caltech.edu/~boyk/ARTICLES.HTM .



> ...the process of sound reproduction is a very unnatural act, and therefore will require invasive procedures in order to
> seem natural.

This is a dramatic assertion which in my experience is false. Perhaps it's true with the kind of performances you record.



> For example, the use of microphones and speakers by their very nature is expansive, so by doing nothing you're
> actually in effect applying an expander.

Where on Earth do you get this? Some speakers do slightly dynamically expand burst signals in certain frequency ranges; others compress slightly; yet others don't do either, at least not within quite a wide dynamic range.




>>>...The widening of a 90 degree cardioid XY pair is just one of many
> processes that must be done,


>>You convert XY to MS, increas the proportion of S, then convert back to XY?


> Actually I use Waves Stereo Imager, which does what I need in the digital
> domain, presumably by that process. I know what you're going to say next, I
> should avoid the extra process and record in MS.

If using condensers, you should use MS for an entirely different reason, which I've described in other threads.



> ...I don't like the idea of a side channel running through any analog gear for fear that some expansion or
> compression might occur disproportionate to the mono channel, which can
> really warp the ste