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Seattle-area audio experts for hire?

dandeliongold

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Hi, we have a recording studio set up in our home in Seattle which includes a PC for recording and playing back audio. We had a dedicated power circuit installed for all of our gear. We noticed that when we plug the PC into the same circuit as the other audio gear, we get a lot of digital ‘hashing’ style noise in the audio signal chain.

Our DAC/Sound card is an RME UFX+ plugged into our PC using a USB cable. Audio is routed between the DAC and other audio devices (like effects and electronic instruments) using a few Redco patch bays (specifically REDCO R196-D25PG TT/DB25 96PT).

It seems like there is definitely some kind of grounding issue happening. When we experiment with different grounding options on the patch bays, they significantly affect the noise. However, we have yet to figure out exactly what is going on, or come up with a solution.

We’d like to hire a professional to come to our studio and diagnose the problem. How would I find someone with the right expertise in the Seattle area? So far I’ve googled around for home theater consultants but haven’t come up with anything very promising yet.

Thanks!
 

Astoneroad

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DonH56

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Do you get the noise when the PC is plugged (and running) in but not connected to the system? If so, can you run a temporary extension cord that puts the PC on another circuit in the house? Like to an outlet in the hallway not on your dedicated circuit... See if the noise changes or not. I am suspecting it is not the actual power line but noise through the PC's audio/digital output interface. Those are notorious for ground loops and noise.

You could also try a "cheater" plug on the PC as a temporary fix to lift the PC's ground line (like https://smile.amazon.com/GE-Polarized-Grounding-Adapter-14404/dp/B00B7PK1TC/ref=sr_1_7?crid=13CPUR2L4O7XC&keywords=ground+lift+plug&qid=1668871060&sprefix=,aps,140&sr=8-7). If the noise goes away, buy a power-line (e.g. Hum-X) or signal line (many available) device that isolates the PC's ground from the audio system.

HTH - Don
 
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dandeliongold

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I've tried Hum X's on various devices, including the computer. Unfortunately no luck. I'm using RME interfaces, so they should be about as good as you can get in terms of interference.

The noise does change characteristic when the computer is on a different circuit. It becomes more of a 60 cycle hum. When it's on the same circuit it's more of a digital hash that changes based on what's going on with the computer. (If it's working hard, it hashes and sputters, if it's not doing anything, it's a more steady buzz)

I've read the Bill Whitlock paper on ground loops and determined that the noise (at least on a per device level) is common-impedance coupling. It is suggested in that paper to use an isolator. However, I have some 15+ devices with send/returns to the RMEs. Attempting to lift ground or try other schemes for connection have not yielded any improvement. Using isolators like Reamps/DIs have helped to some degree, but are not an ideal situation as they change the level drastically, and of course would be a HUGE cost.
 

kemmler3D

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Is it possible you've got some wacky EMI from the PC to the patch bay? That sort of thing is unusual, but given that you've tried messing with the grounding in lots of ways, one wonders...
 
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dandeliongold

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I'm not sure if EMI is a possibility. The RME units are racked near the patchbays, and are only connected to the computer via a USB 3.0 cable. The issue also doesn't happen if I don't create an I/O loop. For example, I have a synthesizer that you can plug audio into it's filter. When I run the synth without it's input connected to the patchbay, the output is clean. When I plug a send from the patchbay into it, the same buzz/hash is present. using an isolator (like a Radial Reamp) seems to remove the noise, but it also drops the audio going to the device significantly. It may be that the noise is just getting equally as quiet.
 

kemmler3D

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It kinda sounds like all the issues are coming from the patchbay and caused by the PC, would that be accurate?
 
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dandeliongold

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It kinda sounds like all the issues are coming from the patchbay and caused by the PC, would that be accurate?
I don't know if it would be entirely accurate to say that. The patchbay does not appear to be the source, but rather passing the noise through. I can modify how loud the buzz is by changing the grounding scheme on the patchbay (bus ground, vertical strap, isolated).

The noise is present even when the computer is off, so this implies that it is some kind of ground loop/ coupling issue between each device and the RME interfaces. (The RME devices will pass audio through their internal digital console even if the computer is off).

However, there does seem to be some kind of interaction between this coupling issue and the PC. If the PC is on the same circuit and plugged into the RME via USB, then the characteristic of the noise changes from a hum to a hash (based on how much processing is being used).
 

Doodski

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I don't know if it would be entirely accurate to say that. The patchbay does not appear to be the source, but rather passing the noise through. I can modify how loud the buzz is by changing the grounding scheme on the patchbay (bus ground, vertical strap, isolated).

The noise is present even when the computer is off, so this implies that it is some kind of ground loop/ coupling issue between each device and the RME interfaces. (The RME devices will pass audio through their internal digital console even if the computer is off).

However, there does seem to be some kind of interaction between this coupling issue and the PC. If the PC is on the same circuit and plugged into the RME via USB, then the characteristic of the noise changes from a hum to a hash (based on how much processing is being used).
I think you have multiple issues at the same time.
 
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dandeliongold

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I think you have multiple issues at the same time.
I would not doubt it. I have a feeling the PC/hashing issue may be separate. However, the above specification should isolate the issue to the ground loop between the RME interface and a specific device (connected via TS audio cables going to and from the RME).
 

Ricwa

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Hi, we have a recording studio set up in our home in Seattle which includes a PC for recording and playing back audio. We had a dedicated power circuit installed for all of our gear. We noticed that when we plug the PC into the same circuit as the other audio gear, we get a lot of digital ‘hashing’ style noise in the audio signal chain.

Our DAC/Sound card is an RME UFX+ plugged into our PC using a USB cable. Audio is routed between the DAC and other audio devices (like effects and electronic instruments) using a few Redco patch bays (specifically REDCO R196-D25PG TT/DB25 96PT).

It seems like there is definitely some kind of grounding issue happening. When we experiment with different grounding options on the patch bays, they significantly affect the noise. However, we have yet to figure out exactly what is going on, or come up with a solution.

We’d like to hire a professional to come to our studio and diagnose the problem. How would I find someone with the right expertise in the Seattle area? So far I’ve googled around for home theater consultants but haven’t come up with anything very promising yet.

Thanks!

I had an audio hash / high freq. noise problem with a PC connected to an RME ADI-2/4 SE Pro via USB. Solved it using a Topping HS02.
 
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