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I've yet to find a definitive answer to this, but Google shows hundreds of people asking questions.

I have an M-Audio M-Track, a $100 USB-based audio interface.

Across all 3 computers I have tried it on, there is a high-pitched whine around 1kHz, similar to the one here: https://dl.dropboxusercontent.com/u/7345145/noise_2.wav

That high-pitched noise is in common between many brands of audio interfaces, as you can hear recordings on Google.

This happens when recording with things plugged in and with nothing plugged in with all possible configurations of the box (phantom power, monitoring, gain, line level, etc.)

It's not a ground loop. It happens on my mac pro when it is running from battery or when plugged in, on a 2006 original Mac Pro, and on my AMD-based desktop, always exactly the same noise, same pitch. I've tried putting a powered USB hub between it and the computer and that didn't help.

High-pitched whining is a common problem across many USB devices but there don't seem to be any answers other than "ground loop." It isn't a ground loop.

Thanks

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  • I don't suppose you've been able to try another unit of the same kind? It could be that there are just a bunch of badly manufactured cards around. Have you tried it just with headphones - not going to a mixer or speakers? I'm no engineer, so you may well know better than me and may be right about it not being a ground issue, but there is some interesting stuff here: soundonsound.com/sos/nov04/articles/computerproblems.htm the bit about USB/firewire and unbalanced connections is perhaps of interest.
    – Mark Durham
    Commented Jul 15, 2014 at 18:29
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    additionally; have you returned the unit to the vendor with the complaint? what was the response? this sounds like a defective unit. and not to be a bore but you could save up some money and spent a bit more on a proper device, starting at $300 you can get something a lot better.
    – Arnoud Traa
    Commented Jul 15, 2014 at 19:14
  • @ArnoudTraa I am open to getting something better, this is from a (small) A/V budget for a facility. Ofc. at some point along the spectrum of quality the question of getting a better transmitter comes up. What I would give for a 16-track pass-through recorder... Anyhow, what did you have in mind?
    – std''OrgnlDave
    Commented Jul 15, 2014 at 19:19
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    The 1 kHz whine is coming from the 1 ms frame rate of the USB signal, by the way. It can get into the audio several different ways, though other than the things you've tried (breaking ground loops, using USB hubs), I think any fix would require modification of the circuit board. @DavidLitke yes, balanced cables will improve ground loop problems
    – endolith
    Commented Oct 15, 2014 at 16:42
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    I have the same problem with Blue Yeti and also tested it with several devices in different environments, this sound comes from the inside.
    – Nik
    Commented Jan 11, 2015 at 17:52

6 Answers 6

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That is the result of bad isolation of either the DAC or the ADC. If the internal circuitry of the interface and the actual capture or playback circuitry share a common power supply, the operation of the electronics itself cause a distortion to the power being supplied to the capture or playback circuits.

Capture and output both rely on a fixed reference level and if this level is not constant, it introduces variations in the actual signal produced. These variations are what you are hearing with that noise. You get the same thing on a lot of computer sound cards and you can notice that it changes frequency when things take power in the computer such as intense processing or hard drive operation.

The best way to avoid this is to use interfaces that have isolated DACs and ADCs (should be listed as a feature) that are given a solid, constant reference level to work from independent of the power variations occurring within the rest of the hardware. Alternately, an if you can provide isolated power from the power supply, that may also help.

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  • I think I'll set this as the question answer, because it's the best info I've found on the 'net.
    – std''OrgnlDave
    Commented Jul 19, 2014 at 18:21
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I have the exact same interface and was hearing the exact same noise, except it was not there when I bought the interface.

It does seem to be a power-supply-related problem, turns out the noise only appeared when I was plugging it into a USB hub, not the computer directly.

So, while this may or may not be the cause of the author's problem, other people in this situation may try different options of plugging/powering the unit, before considering it a faulty unit.

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Well, since I just ruined a recording yesterday, here is another pointer: don't let your microphone cables run across the laptop's switching power supply on the ground. Balanced cables may be good for a lot of electromagnetic abuse, but there are limits.

So keep a distance between the analog and the digital parts of your setup and particularly avoid direct vicinity with switching power supplies and (pretty much the worst) mobile phones.

If your cables run close to the audience and some lady sets her handbag with the phone switched to "silent" rather than "off" next to it, there is little chance that the preamps won't notice the phone bursting out watts of RF occasionally in order to retain contact with its cell tower.

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I've had this problem today with a Focusrite Scarlett 2i2 USB interface and some new Yamaha HS7 monitor speakers.

The problem is likely to be dirty power. However, is simply fixed with the addition of a cheap Ferrite Ring - a magnet basically that is wrapped around your USB power cable to the sound card.

If you're in the UK you can find them at Maplin - http://www.maplin.co.uk/p/ferrite-clip-on-hem3017-n94ab

Worked perfectly for me, hope it does for you!

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Sheez, I had a similar problem on an M-Audio Audiophile USB AGES ago. I'd recommend trying other models and isolating the cause of the problem — RME's price will probably make you cry now but smile years later (TotalMix is still a nightmare UI to use but if you mainly handle routings in your DAW and focus on the awesome sound quality, you're essentially set).

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I had the same problem, the cause was my cinema display connected to a unregulated power source.

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