Whine on USB mixer only when Aud is monitoring

I’m using an Alesis Multimix 4 USB mixer to do voice and keyboard recordings. I hear a whine in the headphones plugged into the mixer, but only when Audacity is recording or monitoring,

The whine goes away when I stop monitoring.

The whine is not perceptible in my recordings.

It is present even if all the inputs on the mixer are disconnected and potted all the way down.

I tried muting each of the audio settings on my PC.

It’s not affected by moving the mixer.

Anything else to recommend? I would greatly appreciate your suggestions.


Gordon Rothman

I wonder if you are picking up interference from your monitor or graphics card. Try minimising Audacity while it is recording and see if you still get the noise.

Good theory, but no luck. I minimized Aud and the whine continued.

What sort of computer are you using? Laptop power supplies will frequently cause interference, though I don’t know why it should only be noticeable when monitoring, but if you are using a laptop, try running it from batteries and see if you still have the noise. If it’s a full size computer, try it with the monitor completely switched off.

The fact that it does not affect the recording makes it more of a minor annoyance than a problem, but I’m still intrigued to know where the interference is coming from.

Hey Steve…

It’s a Dell Desktop PC running XP, and the interference continues when the monitor is switched off. The adapter was connected to a USB port on the CPU itself, but the interference remains when I switch it to a USB hub.

I also tried disconnecting the power source to the audio adapter, but it killed the signal as well as the whine.

It is an annoyance, but it makes it impossible (or at least very unpleasant) to monitor your recording in real time. That’s a problem for my voice recording, and a deal-breaker for overdubbing musical tracks.

I thank you for your time thusfar, and would be happy to hear any other suggestions for diagnosing this.



Let me predict the past. You’re putting your headphones into the mixer with the idea that you’re going to listen to both the computer and your live performance. Meanwhile, the live performance only is going into Audacity for capture and recording.


That mixer will not do that. I bet you’re listening to feedback …eeeeEEEEEEE. It goes away when you shut down Audacity, right? That’s Audacity sending you the mix so you can sing to it. Since this board only has one program channel, it’s also feeding it back to itself.

You need some form of two program channels to do that trick.

I have a larger mixer (Peavey PV6) with Effects Send. I haven’t written this up yet, but I finally got it to work.


I use the mixer main outputs to feed the headphones and that’s it. The Effects Send is the actual microphone feed into Audacity for recording. Effects Send is dry. It doesn’t have the show mix on it. Just the microphone.

The main show channel in the mixer gets both the microphone and the Audacity Playback but it only goes to the headphones. I can hear the performance mix with no delay and no feedback.


Hey Koz, thanks for your note.

I’m actually not expecting the mixer to mix playback and record; I just want to hear a clean version of what I’m sending from the mixer to the PC. I don’t want and didn’t expect anything to come back to the mixer from the PC.

In fact, the whine persists when I do everything I can think of to keep Audacity from playing. I deselect Overdub and Software Playthrough. I turn the speaker slider on the Mixer Panel all the way down.

(I did refer in my note to overdubbing; I was hoping to play back the recorded tracks on speakers while adding a keyboard track that I’d monitor through headphones. That’s an easy workaround; I’ll just monitor the keyboard directly through its own jack.)

So… still no luck. I’d be grateful for any other ideas you have!


sounded like feedback to me

are the data paths through the entire system documented anywhere?

does anything explain the various ways you monitor , overdub, yada yada, and when to use stereo mix versus other selections

<<<I was hoping to play back the recorded tracks on speakers while adding a keyboard track that I’d monitor through headphones.>>>

Yes, that’s why I went through all that business to develop the mixer. My headphone service has the fully mixed show with individually adjustable volumes for Old Show and New Microphone.

I need to sit in the corner and read this again. I use a Mac because Windows makes my head hurt. I bet it makes your head hurt, too.


Did we ever ask you to post a short segment of the sound? Can you? Do you have any place to upload it where we can all get to it? The highest quality the better and include some “silence” so we can get a flavor of the noise by itself.


Now MY head’s hurting. I’m not sure how I’d record the sound – I hear it only on the headphones, not in the Audacity recording.

Well, since we’re reduced to whack job conspiracy theories, Do you have another pair of headphones or earbuds?


Earbuds. Tried. Failed.

It leaves me wondering: what would be the effect on sound quality if I were to just take the analog output of the mixer into a microphone jack? It seems I have a SoundMax card on the PC. (FYI, I’m running all mono) I would have tried it already but I don’t have a long enough cable at the moment

since the output is high level voltage
and the mike is for low level inputs
the distortion (clipping) should make you forget the whine :slight_smile:

that approach is highly NOT recommended

even if you lowered the output control
and lowered the input
if you could avoid the distortion you might get a lot of noise instead of a clean signal

this is a tough one

please tell us you do not have tinnitus
and give us more clues to work with

Well, I’m pretty sure I don’t have tinnitus that’s triggered by Audacity’s monitoring function. :smiley:

I’m running out of clues to report! I’m about ready to suck it up and just live with it.

Again speaking from way out over the cliff, can you make it worse or change it? Can you cause the problem and then gently wiggle cables to see if it changes? Any change at all. Pitch, volume, density. Is it worse on left, right, or about the same. I know you said you’re in mono, but there’s a stereo amplifier delivering the mono show to both of your ears. It is doing that, right?


LOL :smiley:

You’re monitoring from headphones plugged into the Mixer?

Can you route the Audacity output to your computers internal sound card and listen to Audacity through headphones plugged into the computer?

is your cell phone in the same room ?

is the pc in the same room as a cable tv settop box?

are you near a radio /tv transmitter or near a cb or ham user?

cell phone’s in the same room, though its proximity to the mixer or PC seem to have no effect. no to questions 2 and 3.