How to get rid of noise in USB interface

wuubb

New Member
I recently redid my setup with a new laptop and monitor and started getting noise through my interface. This is my setup:
1573152285349.png

I went through and plugged in items alone 1 by 1 until the noise happened. The culprits were the monitor, and the Yamaha keyboard. Both the keyboard and the interface have MIDI ports, so I'm going to try that instead of USB.

The monitor however, is a different mystery:
  • Any output from the dock into any input on the monitor causes noise
  • Plugging into the laptop HDMI directly is fine
  • My TV and my friend's monitor plugged into the dock are fine
The above would suggest that the monitor is problem, yet if I use a cheap USB-C to HDMI adapter on the laptop and connect the monitor, there is no noise.

I have 2 of the same model dock which both behave the same.

Does anyone have any suggestions? The monitor is a brand new Acer, that I bought from Micro Center along with an extended replacement plan (it's a really nice 42in monitor), but not sure who I should contact. I obviously cant use it for what I do but it's not broken in a traditional sense which makes me think they won't do anything.
 
I've been watching this thread hoping someone would have a solution for you. I've run into the same problems and never been able to figure it out. If I connect a synth via USB I get noise through my audio interface so I ended up connecting everything via midi instead. If you ever do resolve this I'd love to hear what the fix was.

My motherboard even has an "isolated" usb jack which I run my Audio Device into (RME BabyFace Pro) but that hasn't made any difference. Switching computers didn't resolve it either - it must have something to do with power/ground loop (at least in my case) but I've never had any luck finding a fix.
 
Have you tried a usb cable with a ferrite bead? Or a usb noise suppressor?



best,
Chris
I have - I even tried buying a PCIe USB card and plugging into that but the same thing happens. I don't even think the synth needs to be turned on. The second I connect that USB cable to my system there is audible noise through the interface and it actually gets recorded as well if I record any input in my DAW. Frustrating! Using midi cables has been a good workaround though.
 

wst3

my office these days
Moderator
I don't have a brilliant solution, but I may be able to help you pinpoint the problem. In generic terms it is referred to as the "Pin 1 Problem", and it describes how noise current can get into an audio circuit if the shield is not terminated properly, or if grounds are not maintained properly. And it is known to be a problem with some USB and Thunderbolt implementations.

From your description it appears that the dock may be the problem, or the dock in combination with other devices.

If it were me I'd probably retrace my steps (you've done a very good job of troubleshooting, I'm not questioning that!)

1) connect the laptop and the audio interface via USB. No noise? Let's hope, because further testing would be hampered if there is noise here. Is your audio interface bus powered? That shouldn't be an issue, but it could be.
2) one at a time plug the non-musical peripherals (keyboard, mouse, drives, etc, but NOT the display) directly to the laptop. If any of them cause a problem set them aside. If all of them cause a problem then the audio interface becomes a suspect.
3) assuming we are doing alright so far connect the dock, but no peripherals - any noise?
4) repeat step 2, but connect the peripherals to the dock instead of the laptop.
I would expect (hope?) that by now we might have found the problem, if not continue along.
5) now connect all the peripherals to the dock at the same time, noise?
6) disconnect all the peripherals and connect the display, noise?
7) reconnect all the peripherals to the dock, noise?

if you've gotten this far then the MIDI devices need to be tested in the same manner - I don't think you'll get this far, but if you do then connect the MIDI devices to the standard MIDI ports, Noise? If not connect them via USB. Noise?

Report back with your results and we will try to make sense of it.

Avoid purchasing any magic solutions, as they seldom work.
 
OP
wuubb

wuubb

New Member
Yea my interface already has a ferrite jacket on both ends, so no luck there :P

@wst3 regarding your steps:
1 - no noise
2 - no noise
3 - no noise
4 - MIDI keyboard and display each cause noise
5 - noise
6 - noise
7 - noise

So the end result is both the MIDI keyboard and the display each cause noise, but only when connected to the dock, not directly to the laptop. This would suggest the dock is the problem.

I have 2 of these thunderbolt docks from Dell and they are great. I did everything with both and they both exhibit the same behavior. Not sure what to do though since it seems like a problem with the design and not the defect of a particular dock so Dell probably wouldn't do anything. Thoughts?

Thanks for the support everyone, much appreciated!
 

NekujaK

Member
After reconfiguring my system a couple of years ago, an annoying hum suddenly appeared. I eventually solved the problem by inserting an inexpensive ground loop isolator in my audio signal path.

That said, your noisy USB issue is ostensibly different from what I experienced. However, the root cause may be the same. If you search Amazon for "usb ground loop eliminator", several USB-specific noise eliminators are available. Perhaps one of these will resolve your issue.

Good luck - I know how frustrating and maddening unwanted noise can be.
 

Nick Batzdorf

Moderator
Moderator
This would suggest the dock is the problem
It suggests you have a ground loop, meaning two paths to ground. The first thing is to ensure that everything is plugged into the same power strip. (Sorry if someone has already suggested that.)

You're not supposed to use ground lifters (i.e. 3-to-2-prong AC adapters) because you can die a horrible death, but I've known people astoundingly close by here who've done that and not worried.

Well, one probably should take that more seriously than I do, because if something goes wrong with your keyboard and it shorts internally without a path to ground and you touch a live wire, the electricity goes through you. Is that likely to happen?

I actually have a 1:1 isolation transformer that effectively does the same thing, only safely.

In any case, ferrite beads are for RF noise - airborne noise, not ground loops. They're not going to help, but at least you're close to isolating the problem.
 

TomislavEP

Active Member
I have had electrical noise problems quite a few times in my studio. I've managed to mitigate and eliminate them by using these precautions:

1) Using the same surge protector for all my gear (with enough outlets for everything)
2) Using UPS unit with AVC feature for powering my system and hardware synths
3) Using stereo DI box in between my monitors and interface (an especially important step)
4) Using balanced (TRS) cables where appropriate
4) Using USB cables with built-in ferrite beads
5) Placing ferrite beads around the audio cables connecting my interface, mixer, and monitors

I hope this list might be of help to someone.
 

wst3

my office these days
Moderator
You have ground loops - everyone has ground loops, they can not be (safely) avoided, and they do not have to cause problems.

An isolation transformer - something that breaks the copper path - resolves lots of noise problems, but the real root problem is designers who haven't a clue about analog signal paths - and make no mistake, USB still relies on an analog signal path!

Plugging everything into the same power strip reduces the area of the ground loop, and therefore it's influence, but it does not remove the loop.

The only guaranteed solution is a proper balanced interface, and some signals (video, USB, etc) are not designed to be balanced. They can be, but it isn't the intent. If all of your audio connections were properly balanced it is highly likely that you would hear neither hum (magnetically coupled noise - typically 60 cycle power line noise) nor buzz (electrically coupled noise - aka RF noise).

The reason is that while the noise would exist, it could not get into the audio circuits. Noise does not contaminate digital signals in the same way, so we almost never hear them, and when they are really bad the signal tends to stop working.

Back to your specific problem - we can ignore steps 5 thru 7, since step 4 exposes the problem. Does the noise appear if either the MIDI keyboard or the display are connected, or only when both are connected?
 

Nick Batzdorf

Moderator
Moderator
Plugging everything into the same power strip reduces the area of the ground loop, and therefore it's influence, but it does not remove the loop.
Mos def, but it's the first step.

An isolation transformer - something that breaks the copper path - resolves lots of noise problems, but the real root problem is designers who haven't a clue about analog signal paths - and make no mistake, USB still relies on an analog signal path!
I believe you, but unfortunately I'm not rich enough to have all my equipment redesigned. :)

Also, neither the 8-track reel-to-reel machine nor the analog mixer I was using when I bought the isolation transformer had USB ports.

:)
 
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JazzDude

New Member
its important to identify the "noise".
Groundloops will bring nasty "HUM" mostly (low frequencies).
High Frequency noise (Hiss) is mostly wrong gainstaging and lots of amp stages in series (each Transistor/OPamp produces hiss). Or a reel to reel tape/Cassette deck...lol .
The Industry should get rid of ALL non symmetric analog 2 line cables and use fiberglass cables in digital area (NON COPPER).
Another tip: keep all boxes and cables far away from huge Transformers (Power amps) else u have new HUM.
 
OP
wuubb

wuubb

New Member
Does the noise appear if either the MIDI keyboard or the display are connected, or only when both are connected?
It happens with either of them, but only when connected to the dock. If I connect the MIDI keyboard and display directly into the laptop everything is fine.
 

dflood

Active Member
So it sure sounds like the dock. Does it have its own power source? I recently tracked down a nasty hum to a crappy power supply transformer.
 
OP
wuubb

wuubb

New Member
Am I right in saying that this is not hum or hiss here but rather a sort of "computer" noise?
It sounds like TV static with some occasional hisses and pops/clicks

So it sure sounds like the dock. Does it have its own power source? I recently tracked down a nasty hum to a crappy power supply transformer.
It does, it's Dell dock so it uses one of their standard power brick AC adapters. Don't remember what the specs are for it off hand but I can check when I get home.

Sounds like that dock is fongula.
The thing is it happens with both of the same model dock that I have, so it's probably something that wasn't considered in the design on Dell's part, not a manufacturing defect, which means they probably won't do anything if I call them. In that case, what options do I have for getting rid of this noise besides abandoning these docks (which are otherwise fine).