Reducing computer noise reaching USB audio interface

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But doesnt computer fan noise dominate acoustically anyway ?
By using a high power PC you certainly create more problems ,a laptop running on battery is whats usually reccomended for lowest noise .
On another forum dedicated to low noise low distortion ADC/DAC's bad power means people end up with less than -100db S/N on devices , which under the right conditions can do -120db.
 
No. I bought silent cooling solutions specifically because I find them unbearable.
The only noisy fans are on the video card. But it never gets too loud.
But the noise in the speakers is out of this world.
Edit: Attached are two WhatsApp audios I showed to a friend. One is with the computer Idle, and the other is in load
 

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  • Noise2.ogg
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Many years ago I set out to make a quiet recording PC , I didnt need massive processing power ,
I used a Nettop (Atom)PC which had a small fan , but by trimming out the OS (XP) I was able to record a few channels without any fan on ,
I used an M-audio transit USB , which has both optical in and out , that kept the computer electrically isolated from the ADC/DAC ground ,
As it was a 12v Mobo I arranged a bank of lead acid batteries , the monitor and router also being 12v devices ran off the same supply ,
So the only thing running off the mains was the ADC/DAC and the speakers ,
There was no annoying noises either electrical or acoustic in nature .
Adding an SSD made it completely silent .
 
Fast USB (USB 2.0, 3.x) isolators are expensive ($300 and up) but could solve problems if only when the audio interface can use external power (not USB). There are also isolators that can be used over I2S bus but these should be built into the audio interface (seldom done). One option is to use ADAT converters or isolated S/PDIF (optical or tx isolated coaxial).
 
I wonder if a max 50-buck semi-pro audio interface might cure that issue, if using balanced connections (optionally with the sleeve / ground disconnected on the subwoofer end). Thinking of something like a Focusrite Saffire 6 USB (used, of course).
 
I have amplifiers with balanced inputs for my main speakers, but I had a Velodyne sub which only had an unbalanced input. I really liked the sub (servo feedback, so really low distortion), so I got one of these Jensen transformers which is optimized for low frequency use:
Jensen JT-112P-2HPC datasheet
Worked great to allow me to incorporate it into my balanced system. Had to take the input assembly apart and punch a hole for an XLR connector.
If you don't want to do that, Jensen sells that same transformer in a little box you can just put right in front of your sub as a ground isolator.
Pro sub isolator with XLR
Home theater sub isolator with RCA
 
I tried a cheapo ground loop isolator. It did the job. BUT, it destroyed lower frequencies.
It was a miniplug cable one.
The ones you mentioned up there look more promising judging by the specs, but the sub has only RCA and balanced TRS inputs as passthrough.
So I would need one that filter stereo, and full frequency response without destroying the signal, if there is such a thing.

I'm hoping that the motherboard replacement(Which is still in warranty) fixes the issue for me since it only happens when connected to the PC. If that doesn't work, I'll try a PSU replacement (Also within warranty)... If that doesn't work, I don't know what to do.
I could try getting a refund for the sub (it has a 3 years warranty, so I still have 1 year and 3 months left). But its weird I only have issue when I connect the whole set up to the PC specifically. Laptop, Switch and PS4 work just fine. Granted the Switch and and Laptop are all DC powered devices, and the PS4 I use the optical out which if I'm not mistaken carries no current, right?
 
a cheapo ground loop isolator. It did the job. BUT, it destroyed lower frequencies.

Yes, making a transformer which can pass low frequencies and has good high frequency response is somewhat tricky.

but the sub has only RCA and balanced TRS inputs as passthrough.

So the sub has the crossover, and the L and R combined audio signals go to the sub, and from the sub then go to the small monitors?
That makes it a little trickier, the transformers optimized for low frequency performance do not have extended high frequency performance.
A standard Jensen isolator would probably work fine, if the system has RCA inputs then the levels are not very high so there should not be a huge problem with LF distortion.

I'm hoping that the motherboard replacement(Which is still in warranty) fixes the issue for me since it only happens when connected to the PC. If that doesn't work, I'll try a PSU replacement (Also within warranty)... If that doesn't work, I don't know what to do.

It doesn't seem likely, you have not described anything else about the system to indicate that it is operating differently than designed or expected.

But its weird I only have issue when I connect the whole set up to the PC specifically. Laptop, Switch and PS4 work just fine.

The PC is probably on the order of 10x higher power than the laptop and PS4, and more like 100x higher power than a Nintendo Switch. Interference is often dependent on the currents involved.

You can get some relatively inexpensive USB isolators, I see some in the range of $10 to $20 on Amazon. The cheapest one doesn't have a case, you could try that and if it works well enough you could 3D print a case for it, or just wrap it up in mylar tape or whatever. Or just pay the extra $10 for one that comes in a case.

PS4 I use the optical out which if I'm not mistaken carries no current, right?

Right, optical connections are electrically isolated. Electrical isolation is what you need, to keep common mode currents from the high power PC power supply from flowing on the audio lines. Optical connections work, transformer isolated S/PDIF would should work, or isolate on the USB side.

Granted the Switch and and Laptop are all DC powered devices

Probably more relevant is that the laptop is low enough power that it would have a much milder AC filtering at the power brick inlet, so much less leakage current. At least I assume you tried the laptop with it connected to the charger, if it was unplugged and only running from battery then that would obviously be a completely different situation than the PC, but if the laptop is plugged in to the charger then it is just a lower power version of the PC.
 
If anything, i'd rather guess the laptop, as well as the consoles etc are NOT using earthed power supplies. Or even if the laptop is earthed, there's likely not a direct connection between output ground, and mains earth.

Good luck getting a refund on that sub ("warranty" is not the same as "return period", i don't think).

  • When I use my active monitors + active subwoofer on my PC with integrated audio I get this horrible static noise.
  • Same with an external DAC (USB powered. Same cable as data source).
  • Monitors + PC, without the subwoofer. No noise.
  • Monitors + subwoofer with my laptop/Switch/PS4. No noise.
  • Monitors + subwoofer + external DAC powered with one of the PC USBs. Noise
  • Monitors + subwoofer + external DAC powered with a wall socket USB(On PS4/Switch). No noise.

I still maintain it's a nasty ground loop. Can't be a coincidence.
 
I just realized that my monitors are in fact NOT grounded. So that might be why I don't get the noise in the first place.
I went ahead and tested a theory...
I did some "Argentinian engineering" and created a ground lift in the sub-power cord using just tape.
Noise is gone.
I know I know... It is dangerous to use ungrounded stuff. But to be fair the monitors are not grounded either.

Will a power conditioner do any difference if I want to keep the sub grounded?
 
I just realized that my monitors are in fact NOT grounded. So that might be why I don't get the noise in the first place.
I went ahead and tested a theory...
I did some "Argentinian engineering" and created a ground lift in the sub-power cord using just tape.
Noise is gone.
I know I know... It is dangerous to use ungrounded stuff. But to be fair the monitors are not grounded either.

Will a power conditioner do any difference if I want to keep the sub grounded?
I wonder if a max 50-buck semi-pro audio interface might cure that issue, if using balanced connections (optionally with the sleeve / ground disconnected on the subwoofer end). Thinking of something like a Focusrite Saffire 6 USB (used, of course).

No, "power conditioners" don't do jack regarding ground loops.

Take your pick (but don't pay more than 40e for one):
https://www.ebay-kleinanzeigen.de/s-saffire-usb/k0
 
If you want to use your sub, you'll want an audio source with balanced line outputs.

Worst case, as i mentioned in an earlier post, you might also need to disconnect the shield from one end of the balanced connection (leaving only the "hot" and "cold" connected). Testing should reveal which end is more beneficial (lower noise) to disconnect the shield from.
 
I think you do need true galvanic isolation to guarantee a solution to this problem.
I've always been a fan of using transformers to do it.

Depends on the quality of the transformers of course, but I've found this unit pretty effective: https://artproaudio.com/framework/uploads/2018/06/ss_dti.pdf
Not cheap, but nicely presented, and has comprehensive connection options, and a pretty good spec.

I've even used one of these on occasion: Behringer HD400 Ultra-Compact 2-Channel Hum Destroyer Passive DI Box - Andertons Music Co.
Very cheap, but performs way better than I expected!.... ( No detailed spec sheet though - typical Behringer!)
 
Testing should reveal which end is more beneficial (lower noise) to disconnect the shield from.

Keep the source end connected, lift at the receiver end. See papers by Muncy, Whitlock, et al. for more detailed explanation, but essentially the shield will be driven by source common mode, so signal common mode noise will not "see" that capacitance. If the receive end is connected but not source end, the common mode noise flows into that parasitic capacitance, and any imbalance causes common-mode-to-differential-mode conversion.
 
Thanks for all the help and great suggestions! I'll check the Behringer device once I'm back from my vacations
 
An update from my situation. The underlying problem seemed to be the X570 motherboard inducing loads of noise on the USB bus power lines.

I managed to dramatically reduce the noise even further by employing several of the suggested measures:

1) Added a PCIe USB expansion card with its own SATA power input, so it's using super clean power and ground from the PSU instead of the power lines that have traversed the motherboard. (e.g. https://www.amazon.co.uk/dp/B08DFTJ1QH).

2) Placed a USB galvanic isolator between the PCIe USB card USB port and the USB cable feeding the Maya44 (e.g. https://www.aliexpress.com/item/4000047053305.html)

3) Placed clip-on ferrite beads on the USB cable (e.g. https://www.amazon.co.uk/dp/B01MG8GQ1F)

4) Placed a clip-on ferrite bead on the mains power cable feeding the Behringer DX2000USB mixer

NB: Do NOT be tempted to put ferrite beads on any audio lines. Only use them on 50/60Hz mains power lines, DC power lines and balanced digital signal cables.
 
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