Question about M-Audio Omni problem

[TNKS]

Hello,

I have a problem involving a balanced signal and my M-Audio Omni Studio.

I've been using the Omni Studio for a few months now. For the most part,
I've been happy with it. The basic layout of the Omni is two inputs, Lines
1 and 2, with kind of non-so-impressive pre-amps. . . and two inputs without
pre's, Lines 3 and 4.

I have a stand-alone pre-amp has a convenient knob that lets me output
either a mic-level signal or a line-level signal over the balanced XLR
output. When I run a balanced mic-level signal to the XLR inputs of either
Line 1 or 2's pre-amp, everything sounds sort of fine. However, when I run
a balanced line-level signal through the TRS jacks of either Line 3 or 4, I
get a considerable loss of bass signal among other tonal-differences (I'm
recording a bass guitar). It really sounds to me like the Omni isn't
handling the balanced signal correctly and there's inappropriate signal
cancellations going on.

Does anyone know what might be going on with Lines 3 and 4? I recorded the
balanced output of my pre-amp as a stereo signal, and its output looks good,
with the appropriate phase-shift between the two signals, so I'm assuming
the problem is with the Omni. I really don't like the idea of going through
the pre-amps of Lines 1 or 2. It's just adds noise and colors my signal
unnecessarily. I bought the Omni with the idea that I would seriously put
at least three of the lines to use.

Is there any reason to believe that M-Audio paid more attention in designing
the main lines of the Omni, and neglected inputs less likely to be used? If
so, what other audio interfaces might someone recommend. I like the fact
that units like the Omni have convenient montoring outputs, like phone outs.
How do the Aardvark audio interfaces compare to M-Audio's? Aardvark seems
to pride itself on it's noise-prevention, and that caught my attention. I'm
looking for something that offers a similar configuration to the Omni, but
without this balanced problem, maybe better ADCs, less noise, and more
dynamic range couldn't hurt. I'm willing to spend a few more hundred
dollars for such an upgrade, but I don't think it would be wise to buy a
unit with many more than 4 input channels. I'm really open to any
suggestions as far as recommendations are concerned.

This is kind of a first pass questioning of this problem. I'll probably end
up refining my questions as I have more discussions.

Thanks for reading this post, and thanks in advance for those that respond.

-TNKS



--
Note: To reply to me personally, you'll have to remove the "NOSPAM." domain
extension from the address I've supplied.

[Mike Rivers]

In article <zZV4b.6149$Lk5.561@newsread3.news.pas.earthlink.ne t> youlost@NOSPAM.earthlink.net writes:

> I have a stand-alone pre-amp has a convenient knob that lets me output
> either a mic-level signal or a line-level signal over the balanced XLR
> output. When I run a balanced mic-level signal to the XLR inputs of either
> Line 1 or 2's pre-amp, everything sounds sort of fine. However, when I run
> a balanced line-level signal through the TRS jacks of either Line 3 or 4, I
> get a considerable loss of bass signal among other tonal-differences (I'm
> recording a bass guitar). It really sounds to me like the Omni isn't
> handling the balanced signal correctly and there's inappropriate signal
> cancellations going on.

It's not a cancellation thing, but it might be a wiring thing. Did you
build the cable that you're using to go from the preamp to the line
inputs on the Omni? Or do you know how it's wired? Is it XLR-TRS, or
XLR-TS? There are several possibilities for wiring a cable like this,
none of them clearly standard, and some of which may be incorect for
your particular set of outputs and inputs.

Open up the connectors and see how it's wired.

> Is there any reason to believe that M-Audio paid more attention in designing
> the main lines of the Omni, and neglected inputs less likely to be used?

No, other than that they probably put an additional stage of
amplification on those that can accommodate microphones. It's possible
that the "line" inputs aren't actually balanced, and that can affect
certain balanced output configurations (but not others).



--
I'm really Mike Rivers - (mrivers@d-and-d.com)

[TNKS]

> > I have a stand-alone pre-amp has a convenient knob that lets me output
> > either a mic-level signal or a line-level signal over the balanced XLR
> > output. When I run a balanced mic-level signal to the XLR inputs of
either
> > Line 1 or 2's pre-amp, everything sounds sort of fine. However, when I
run
> > a balanced line-level signal through the TRS jacks of either Line 3 or
4, I
> > get a considerable loss of bass signal among other tonal-differences
(I'm
> > recording a bass guitar). It really sounds to me like the Omni isn't
> > handling the balanced signal correctly and there's inappropriate signal
> > cancellations going on.
>
> It's not a cancellation thing, but it might be a wiring thing. Did you
> build the cable that you're using to go from the preamp to the line
> inputs on the Omni? Or do you know how it's wired? Is it XLR-TRS, or
> XLR-TS? There are several possibilities for wiring a cable like this,
> none of them clearly standard, and some of which may be incorect for
> your particular set of outputs and inputs.
>
> Open up the connectors and see how it's wired.

Hmm, the cable I'm using is a Monster Cable StudioLink 500 XLR-TRS
interconnect. I just unscrewed the connectors off on both ends to see the
wiring. It's as follows:

Pin 1 -> Sleeve (looks to be a ground line)
Pin 2 -> Tip (it's a white wire)
Pin 3 -> Ring (it's a black wire)

It's true that the A/B test I described above, my XLR-XLR cable was a Studio
Pro 1000 cable (higher end). It's possible that I'm just noting the
difference between the two cables. If that's the case, then I'm really
impressed with the SP1000. But I'm not convinced that that's the case.


Also, I'm still really interested in how people think the Aardvark 24/96
matches up against the M-Audio Omni Studio. I just heard someone say that
the ADCs are better in the M-Audio line. Anybody here have any opinions?


Thanks,
TNKS

[Ricky W. Hunt]

"TNKS" <youlost@NOSPAM.earthlink.net> wrote in message
news:hTa5b.6348$tw6.5870@newsread4.news.pas.earthl ink.net...
> > > I have a stand-alone pre-amp has a convenient knob that lets me output
> > > either a mic-level signal or a line-level signal over the balanced XLR
> > > output. When I run a balanced mic-level signal to the XLR inputs of
> either

I've started noticing some screwy stuff on my Omni which I don't think acted
like this before. (More noise, etc.) One thing I've been trying getting
someone to confirm for me (but having no luck) is the fact that the Stereo
Aux In's swap channels when used as recording inputs! When using them as
monitors only they work one way and when you depress the switch to record
them right and left are swapped! WTF?