Audio Interface, periodic buzzing

[Koile]

Hey,

so I got a new Motu M2 Interface about a month ago. Since then there are periodic buzzing sounds coming from the Headphone Amps at "random" times. Sometimes it runs 3 hours without a Problem and sometimes the buzzing happens twice in 5 minutes. Turning the Interface off and on again "fixes" the buzzing temporarily.

The output meter isn't showing anything of it and I already sent the first unit back and received a new one, with the same result. So at this point I am suspecting some Problem with my PC. I am not unfamiliar with how to setup a PC properly for Audio Production, so I already worked through "all" the common steps. Got a suspicion, that it might has to do with my PSU, which is an older unit... but that's really just a guess into the dark.

I'm working on Windows 10 with fairly new Hardware and I'm starting to run out of ideas. I also recorded the buzzing ( https://voca.ro/1llmN9gokfKO ). Sorry for the noisy Background...

I would really appreciate any idea or advice on how to figure this out.

Edit: Words

[James Perrett]

Does the level of the buzzing change when you adjust the headphone level control? If it doesn't then it looks like it could be a power supply issue but, if possible, try the interface on another computer so that you can be sure that it isn't something in the interface causing the issue. If the replacement interface is from the same batch as the original interface then it is possible that there is an issue with the whole batch.

[Koile]

First off, thanks for the (quick) reply.
As far as I am aware the level of the buzzing stays the same regardless of output volume, but I'm gonna have to test this out once the buzzing reappears to make sure. But there needs to be output volume for it to be hearable at all.

I tested the Interface on my Laptop for roughly 5 hours, without any issues appearing. Since it's so sporadic, I will probably test it out again for a longer period just to be sure.

[Airfix]

5 hours without interference - joy . It could be mobile devices - your mobile devices

[Drew Stephenson]

Intermittent problems are a complete PITA. I'd suggest keeping a notepad handy and write down location, time of day, and what other kit is in use.
You might be able to identify a pattern.

[Koile]

Intermittent problems are a complete PITA. I'd suggest keeping a notepad handy and write down location, time of day, and what other kit is in use.
You might be able to identify a pattern.

Will do that, thanks. What exactly do you mean with "other kits" ?
I had an UR22 before for 10 Years and never experienced something like that. I looked around a bit and came across Ferrite Rings which could reduce electromagnetic interferences that effect the usb cable. I am also thinking about getting a new PSU, but i would rather first try to eliminate the issue in other ways.

[Watchmaker]

That sounds a lot like a radio signal to me so I wonder - are you near an airport, police station, hospital, etc? (I used to operate electronic warfare instruments in the Navy which makes me think it's an intentionally transmitted signal source)

I'll suggest to make sure you're using balanced cables where appropriate and check for RF emitters in the area. Could just be your cell phone, though that generally has a distinct character.

[Drew Stephenson]

Will do that, thanks. What exactly do you mean with "other kits" ?

Just whatever else is connected or in use at the time. It should help identify if there's something that you're using that's causing the problem.

[Wonks]

The buzzing (more beeps than a buzz) in that sample is very regular, with them coming roughly 1.4 seconds apart or around 43 BPM.

That's a strange sort of time period and rules out a lot of possible causes.

Any external effects plugged in with a slow tempo, or any delay or chorus/flange/phaser with that sort of speed setting?

Any slow click track that could be leaking through?

Are you wearing anything like an Apple watch or a Fitbit wrist monitor that may be producing a signal that's getting picked up?

[Koile]

Will do that, thanks. What exactly do you mean with "other kits" ?

Just whatever else is connected or in use at the time. It should help identify if there's something that you're using that's causing the problem.

Ah that makes sense. I disconnected everything but mouse, keyboard and interface. The buzzing unfortunately reappeared, but I now figured out that it disappears by itself after ~ 30 seconds. Gonne Test some more and will probably then try a new PSU and see from there. Will post an update if I find out something new. Thanks again for the effort and time.

[Koile]

The buzzing (more beeps than a buzz) in that sample is very regular, with them coming roughly 1.4 seconds apart or around 43 BPM.

That's a strange sort of time period and rules out a lot of possible causes.

Any external effects plugged in with a slow tempo, or any delay or chorus/flange/phaser with that sort of speed setting?

Any slow click track that could be leaking through?

Are you wearing anything like an Apple watch or a Fitbit wrist monitor that may be producing a signal that's getting picked up?

Thanks for the reply. Unfortunately nothing of the above checks the mark. It's really odd that it's such a periodic noise. I even had someone else tell me in another Forum, that I probably use some kind of demo/trial version of some software... which it really sounds like, but of course isn't the case. But I now got 2-3 people and myself gravitating towards PSU or grounding issues.. maybe I get "lucky" there.

[Koile]

Just wanted to give an Update:
After testing out some things and not getting any result, I was close to buying a new PSU (Probably will do that anyway in foreseeable time, thinking about one from Seasonic), but before I did I switched my graphics card with an older one I still had here and so far, after more then 6 hours of runtime, no buzzing whatsoever. I am still careful with predictions but it actually seems like it was the GPU causing interference.

[Drew Stephenson]

Interesting. I think that's the first time I've heard of that being a problem but fingers-crossed you've found the culprit.
Thanks for letting us know, it's good to close the loop on these things.
Good luck.

[James Perrett]

It is certainly possible that it is graphics related. Graphics cards take quite a bit of power and any resistance on the ground connection between the graphics card and the power supply could cause problems if the USB ground uses the same track on the mainboard as the graphics card.

It may be worth checking that all the connectors in your computer are clean and tight. It may also be worth seeing if there are any USB connectors (like front panel connectors) that come from a different place on the mainboard.