OT: M-audio interface making noise

[Dave Labrecque]

Any ideas on this?

I just installed a couple of M-audio Fast Track Pro USB interfaces into a client's studio. I'm getting a high-pitched whining sound from the line-level outputs of both units. But not from the headphone outs, oddly. Also -- I only hear it when a program's audio engine is active. So, for example, for Audacity it's all the time. For SAW Pro, it's only during playback. I can attenuate the whine by making different selections in the FTP control panel. BUT -- I also get the whine when I move the output cable from the FTP to the computer's integrated audio output, though I hadn't noticed the noise before I installed the FTP's.

I'm feeding a little Behringer mixer with the outputs of the FTP's. I tried running a common line between the chassis of the mixer and both computers, but it didn't help. I tried lifting the ground on one of the computers; it didn't help. There are a couple other sources feeding the mixer that have grounded AC plugs. I guess I could try lifting those, too. I'd rather not have an on-going studio powered through ground-lifted AC plugs, though.

Really appreciate any ideas you battle-hardened techies might have -- before I return the FTP's to B&H and replace them with something else that will exhibit the same issue. :(

[DaveS]

Is this a laptop or desktop computer? Try using a ground lifter on each item, one at a time, and see if it goes away. Or if it's a laptop, try running it on battery. If it does then you're probably getting digital hash back thru the power system ground. I had a problem like this with my laptop and Fast Track Ultra. I have an issue with the laptop power supply. If it is a ground problem you should not run the ground lift* all the time....try finding a line isolator or something similar. Also, try disconnecting the behringer mixer and take it out of the system. Listen to headphones and see if the noise is gone. Make sure you use balanced audio cables from the ftp to the mixer too.

* The ground lift thingy is actually an adaptor used to attach standard 3-prong grounded cables to 2-prong oulets. The ground tab is supposed to attach to the screw on the outlet. However in a testing situation-and you know an idiot did not wire your house power, this is a good way to trace equipment ground issues. Don't connect the tab when testing. Also, it won't help test the house electrical...

[Soundguy]

Any ideas on this?



Just a wild guess, but two things I would check would be balanced vs. unbalance outputs, and RF interference from the computer ... or video field interference from the monitors or video card. (I'm probably not describing that correctly, but you know ... move the MAudio units and see what happens)

Soundguy

[Dave Labrecque]

Just a wild guess, but two things I would check would be balanced vs. unbalance outputs, and RF interference from the computer ... or video field interference from the monitors or video card. (I'm probably not describing that correctly, but you know ... move the MAudio units and see what happens)

Soundguy

Thanks.

I did try moving stuff around to see if it was an RF thing, but it made no difference. :(

[Dave Labrecque]

Is this a laptop or desktop computer? Try using a ground lifter on each item, one at a time, and see if it goes away. Or if it's a laptop, try running it on battery. If it does then you're probably getting digital hash back thru the power system ground. I had a problem like this with my laptop and Fast Track Ultra. I have an issue with the laptop power supply. If it is a ground problem you should not run the ground lift* all the time....try finding a line isolator or something similar. Also, try disconnecting the behringer mixer and take it out of the system. Listen to headphones and see if the noise is gone. Make sure you use balanced audio cables from the ftp to the mixer too.

* The ground lift thingy is actually an adaptor used to attach standard 3-prong grounded cables to 2-prong oulets. The ground tab is supposed to attach to the screw on the outlet. However in a testing situation-and you know an idiot did not wire your house power, this is a good way to trace equipment ground issues. Don't connect the tab when testing. Also, it won't help test the house electrical...

Thanks for the ideas.

Two desktops, two FTP's, one mixer. I actually had the whine before I even pulled the second FTP out of its box.

Remember -- I said that the noise does not appear in the headphone output of the FTP's.

I guess I could try more ground lifting stuff. If I do have success with moving a ground-lifter around, what's the permanent solution? You mention "a line isolator or something similar". What's that? Is that the only solution in such a case?

I thought tying the chassis grounds together would fix such an issue. Are power ground and chassis ground not necessarily the same thing?

[Dave Labrecque]

FWIW...

I pulled the power plugs on related gear to rule out ground loops. Nuthin'.

I replaced the USB cables. Nuthin'.

I added a powered USB hub in-line. Nuthin'.

(those last two were successful fixes for some users on the M-audio forum)

Bottom line is I couldn't get rid of a noise that was down around -68 db. Just enough to be a PITA. I pulled both FTP's and went back to the integrated audio setup we were using before -- no such noise. ARGH.

Everything goes back to the retailers... and I start over looking for a budget-level external audio interface that's not noisy. :mad: :o

[Soundguy]

FWIW...

I pulled the power plugs on related gear to rule out ground loops. Nuthin'.

I replaced the USB cables. Nuthin'.

I added a powered USB hub in-line. Nuthin'.

(those last two were successful fixes for some users on the M-audio forum)



I don't think you mentioned if the computer was a laptop or desktop, but if it's the later, I wonder if it could be the UBS controller card picking up interference from something else in the computer.

I had a very similar experience with a low budget audio card in a slot, but the noise went away when using the pro audio interface in the same computer that was connected to outboard converters via lightpipe.

Soundguy

[Dave Labrecque]

I don't think you mentioned if the computer was a laptop or desktop, but if it's the later, I wonder if it could be the UBS controller card picking up interference from something else in the computer.

I had a very similar experience with a low budget audio card in a slot, but the noise went away when using the pro audio interface in the same computer that was connected to outboard converters via lightpipe.

Soundguy

I believe I did mention that it's two desktops.

It's definitely an "analog whine", not ones and zeros noise, so I don't see how it could be coming in through the USB controller. Unless you mean some kind of analog noise sneaking in the conductors.

I guess I'll just keep trying stuff till I get something that's nice 'n' quiet. Hopefully. :o

Part of the problem is that I'm limited to external hardware because these are low-profile boxes; I haven't been able to find anything other than consumer-grade low-profile audio PCI or PCIe cards. If anyone knows of anything... I'm all ears.

[Soundguy]

It's definitely an "analog whine", not ones and zeros noise, so I don't see how it could be coming in through the USB controller. Unless you mean some kind of analog noise sneaking in the conductors.



I was thinking some sort of RF or magnetic field noise cause by stuff like hard drives spinning up ... which was happening in my situation.
Soundguy

[Dave Labrecque]

I was thinking some sort of RF or magnetic field noise cause by stuff like hard drives spinning up ... which was happening in my situation.
Soundguy

Interesting. Well, this was a very constant whine. One that would change with audio engine engagement and I/O settings changes in the driver control panel. :confused:

[Soundguy]

Interesting. Well, this was a very constant whine. One that would change with audio engine engagement and I/O settings changes in the driver control panel. :confused:

My noise would change with editing moves on the screen such as highlighting an area or moving a window around ... but only heard on the cheap soundcard, not the pro audio interface in another slot, or if an external hardrive started spinning up.

...not so much of a constant whine in my case.

Soundguy

[jazzboxmaker]

Odd one Dave- maybe a cooling fan in the box, cpu fan- hold them stopped with your finger for a couple of seconds:confused: