Reducing computer noise reaching USB audio interface

[michaeljtbrooks]

Hi All,

I'm struggling with graphics card, CPU and motherboard noise leaking onto the USB lines. What other things can I do to reduce the noise (without replacing my computer)?

I have a Maya 44 USB audio interface. There is a faint high-pitched whine with bursts of white noise when the graphics card is doing something such as rendering moving windows around. I have managed to halve the noise by moving the Maya 44 from being connected directly to the motherboard USB ports, to behind a high quality powered USB hub, but it is still annoying me. I've tried upgrading the USB cables to extra shielded ones with RF chokes etc, but the noise persists.

Is there such thing as a PCIe USB card which provides USB ports with very low noise?

 

[Khron]

What else is connected to the Maya 44? Just considering the possibility of some ground-loop / earthing issues. I don't suppose you have a laptop you could test it with, as well?

 

[michaeljtbrooks]

It's connected to a Behringer DX2000 mixer. All the audio kit and computer kit comes off the same wall socket, which is branched out using two 6-way mains extensions (fused and total draw is well within 13A).

I get the same sort of noise if I use a cheap USB sound card dongle with a headphone output and plug my headphones into it, which is why I think it's coming off the computer internals.

I've not tried it on my laptop, will give that a go.

 

[buckethead]

The problem will be related to bad ground-layout/ground-loops both inside the computer and with external wiring.

There's an article on SOS, maybe you'll get some info out of that:
https://www.soundonsound.com/sound-advice/q-how-can-rid-my-pc-annoying-background-noises
USB and grounding is almost always a huge mess... some people put tiny strips of tape inside the USB connectors to isolate the GND pin on one side of the connector... but it's trial and error

 

[cyrano]

Open up the PC and inspect grounding screws. Tighten if needed. Sometimes, this can make a difference...

The most reliable way to get rid of PC noise, is using an optical USB isolator. Unfortunately, the good ones are expensive.

What I've also done, is cutting the 5V supply wire in the USB cable. In rare cases, this also works. Obviously, if the interface is USB powered, you need to connect a good external 5V power supply.

 

[kike]

My friend had behringer audio interface and you can hear hard disc spinning on the monitors.The noise was so loud he couldn't stand it. He cut the ground and 5v wire from the usb cable and connected interface on external power supply (cheap wall adapter). The noise was gone.

 

[Rob Flinn]

I have had this with 2 usb interfaces used with laptops. One was a Mbox 2 & the other which I currently use in the workshop is a Native instruments. It also doesn't matter which laptop I have used. I think over the years I have used maybe 4 different laptops all with the same issue. My solution was to isolate the outputs with a pair of sowter transformers I had lying around. What is annoying is that it seems one either has to cut the usb cable & use another psu or use isloating transformers, neither of which is particularly elegant, and takes away from the simplicity of what should be happening.

 

[oldskool1]

I used to have this problem with older USB interfaces. In fact, I still have a Behringer stereo USB audio interface which retails for $29 that exhibits horrible performance and computer noise interference, but at the same time I'm amazed that they can produce something so low cost.

I now have a MOTU M2 interface and it's remarkable how clean it is, considering how ugly USB power can be. It can only be powered by the USB bus, and I can't detect any computer noise whatsoever in the audio. The supply filtering is amazing. There is an in depth review on AudioScienceReview.com where they put it through rigorous tests and they are also impressed by it's performance. I opened it up and it uses THAT microphone preamp and driver chips which are optimized to run off the 5V supply, with a 3.3V option! 10 years ago this performance would have cost >$1000, and I paid $169 for this thing. The D/A's are clean too.

I think a lot of the new USB interfaces are this good... my friend has a new RME interface which he says is also super clean.

 

[skipwave]

I can attest that both the RME Babyface and Digiface USB have surprisingly clean outputs, but still some low level bus power noise compared to units with dedicated power supplies.

I use the Digiface everyday for casual listening, running the headphone output to my near field monitors. There some noise picked up in the right channel that doesn’t appear in the left which tells me that it’s the unbalanced nature out the outputs at issue. The right channel through the speaker and either channel through phones is super low noise.

 

[samplebias2]

I have the RME Babyface Pro and always use the external power source- without it there is a lot of whine/noise/interference. Soon as I enable the wall-wart power supply, it gets nearly silent. Theirs are expensive, I forget if mine is OEM or aftermarket but whatever it costs it's totally worth it.

 

[scott2000]

Theirs are expensive, I forget if mine is OEM or aftermarket but whatever it costs it's totally worth it.

Not sure if the locking feature is what makes it expensive..but yeah, looks like it's a 12v maybe 2amp supply..?

https://www.ebay.com/itm/1853351594...MI84S74LSK9wIV9ciUCR2LnwiSEAQYBSABEgJ1yvD_BwE

 

[Newmarket]

I use the Digiface everyday for casual listening, running the headphone output to my near field monitors. There some noise picked up in the right channel that doesn’t appear in the left which tells me that it’s the unbalanced nature out the outputs at issue. The right channel through the speaker and either channel through phones is super low noise.

Hi, not familiar with that particular kit but can you expand on why those observations point to the unbalanced output as the key thing ?

 

[Newmarket]

What I've also done, is cutting the 5V supply wire in the USB cable. In rare cases, this also works. Obviously, if the interface is USB powered, you need to connect a good external 5V power supply.

I've done that too with some USB DACs. But the result very much depends on the other kit connected. The 0V (GND) connection remains intact so that can still be an issue. Some sort of 0V decoupling via parallel R/C network and/or parallel diode network might be of benefit.

 

[Bo Deadly]

Hi All,

I'm struggling with graphics card, CPU and motherboard noise leaking onto the USB lines. What other things can I do to reduce the noise (without replacing my computer)?

I have a Maya 44 USB audio interface. There is a faint high-pitched whine with bursts of white noise when the graphics card is doing something such as rendering moving windows around. I have managed to halve the noise by moving the Maya 44 from being connected directly to the motherboard USB ports, to behind a high quality powered USB hub, but it is still annoying me. I've tried upgrading the USB cables to extra shielded ones with RF chokes etc, but the noise persists.

Is there such thing as a PCIe USB card which provides USB ports with very low noise?

It looks like that Maya USB is all unbalanced connections? That's not good for interconnecting gear that is separately earth grounded because the 0V analog I/O of the USB is defined by your computer whereas the 0V of the Behringer mixer is defined by the earth ground. Because of this separation, you can get differences in potential (aka voltage) between the 0V. Is the computer earth grounded? Chances are, it is not. So you effectively have 0V defined by the Behringer mixers earth connection at the wall and then the USB interface and computer are "floating" off of that. All of that stuff can pickup interference. Especially if the interconnecting cables are long.

One time I measured the voltage difference between the 0V of a USB audio interface connected to a PC and some other circuit that I was testing that had an earth ground and it was like a couple hundred mV different. I then measured current and it was 6 mA. That's not right.

Try this: Take an extension cord with an earth ground prong and plug it into the power strip that your Behringer mixer is plugged into. Then insert some fat wire or bit of metal into the ground prong hole at the other end of the cord. Obviously you want to be careful not to stick things into the other holes or you'll get shocked and die. But if you don't die, run your test, listen to the noise and then see if there's a difference when you touch the fat wire / bit of metal to metal parts on the USB interface like the 0V of one of the USB I/Os, the case, a screw or similar. If this reduces the noise, this is a clue that what I described above is at least part of the issue. Some gear has a thumb screw for grounding it in scenarios like this.

Pro gear is mostly balanced which will greatly minimize issues like this. Also, some computers are a lot quieter than others. Generally speaking, if you have a low-powered consumer laptop, it will be quite compared to some hulking gamer PC that's chugging power. And old computers are nasty sources of noise by comparison.

 

[michaeljtbrooks]

Newmarket said:
I've done that too with some USB DACs. But the result very much depends on the other kit connected. The 0V (GND) connection remains intact so that can still be an issue. Some sort of 0V decoupling via parallel R/C network and/or parallel diode network might be of benefit.

I did muck around with this idea and built a USB cable with power line RC filtering, but it ended up just picking up other sources of noise because of me introducing gaps in the screening.

Bo Deadly said:
Try this: Take an extension cord with an earth ground prong and plug it into the power strip that your Behringer mixer is plugged into.

Thanks for the suggestion! Connecting earth to the Maya44 case made no difference and without this link the earth-to-maya44-case resistance was miniscule (0.3ohms). Connecting the Maya44 case to the Behringer case also made no difference. I can't get at a 0V pin without introducing a screen break or opening the Maya case which invites a lot of noise.

Putting the powered USB between the Maya44 and the computer helped quite a bit. We're talking about -80dB of noise here with that in the circuit. Enough to annoy me but not really noticeable on most recordings.

Also, some computers are a lot quieter than others. Generally speaking, if you have a low-powered consumer laptop, it will be quite compared to some hulking gamer PC that's chugging power.

My rig is definitely in the "hulking gamer PC" category, though is new with a high end case (Ryzen 9 3950X, water cooled, nVidia 2060 Super, proper Corsair PSU).

My main limitation for balanced lines is the Behringer DX2000 mixer which only has balanced inputs on the mic channels. I use my setup for radio broadcasting from home, so 3+ stereo faders is a necessity, which severely limits choice of desk. I've also modded it to provide mic channel speaker muting, so am reluctant to change it.
(We use an X32 digital desk in the main studio, but its frequently getting sent back to Behringer to be fixed. Love the desk's features, hate the lack of reliability.)

 

[Khron]

So how many ins and outs do you need, between your mixer and your computer?

Just starting to think it might be easier to just get a newer and better (or more "proper") interface, even from the used market. Rather than wasting time, energy and parts trying to put band-aids on a seemingly marginal design.

I don't think i've heard of any horror stories involving bus-powered 2-4 channel interfaces made in the last decade or so, for what it's worth...

The black Maya44 USB seems to be from 2003 or so? Even the white USB+ is from 2007...

 

[Rob Flinn]

I don't think i've heard of any horror stories involving bus-powered 2-4 channel interfaces made in the last decade or so, for what it's worth...

I use a Native Instruments Komplete 2 usb interface, which is currently available which has this noise problem. So now you have heard of one.

 

[Rob Flinn]

As I said previously the best way I have found to eliminte this noise is to use isolating transformers. I prefer this to having hacked about USB cables, or another external psu. In both the cases where I had this problem using my isolator box completely eliminated the problem & didn't just drop the noise to a useable level. But each to their own !

 

[michaeljtbrooks]

My Maya44 USBs are 3 years old, no idea when the model was last revised. I have two, though the noise problems are present when one, the other or both are in use.

I need a minimum of 3x2 outputs (stereo track 1, stereo track 2, stereo beds/sweepers), but ideally 4x2 (stereo track 1, stereo track 2, stereo bed/sweeper 1, stereo bed/sweeper 2) and 1x2 inputs (stereo mixed audio for streaming out)

I used to use the amazing M-Audio 1010LT, but then upgraded my PC to one without the old fashioned PCI slot. I use Linux which limits my range of interfaces a little bit.

If anyone can recommend an 8+ line output, 2+ line input, Linux compatible, PCIe or external audio interface for a reasonable price, I'd be most grateful.

 

[cyrano]

I'd take a long and hard look at the PC, it's PSU, cabling and case. If breaking the screen on the USB cable makes it a lot worse, you've got a real hard noise source somewhere.

Does the noise get worse if you take the lid off the case?

I've had this with a HP3000 workstation class PC a number of years ago. Nice machine, easy to expand/service, but very, very noisy. Just tightening some screws inside made it a lot quieter. That guy had an RME BabyFace attached. The noise radiated even through the venting holes of the case. I screened those with fine mesh and that made that DJ station silent.

We see a lot of these Maya 44 interfaces used by DJs and in general they're not a problem.

You mentioned radio. As in FM broadcast? Or internet streaming?