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Discussion Starter · #1 ·
I have a home theater PC and when I use the scroll wheel with an internet browser open my DIY subs (approx 20ft away) exhibit a sort of buzz while scrolling. My DIY subs are hooked up to a cleanbox which adds a fairly high analog gain.

It happens both with the graphics card and the on-board HDMI output. I've tried multiple HDMI cables. I also added Ferrite chokers up and down the signal chain with no improvement. I've also tried wireless and wired mice to rule out IR issues.

Oddly enough, it happens with the receiver powered down too (the amp is still on 20ft away). The signal chain is PC to TV to eARC to Reciever to sub out to MiniDSP to Cleanbox to amp to sub. So it happens somewhere between there

Any ideas? I'm completely defeated.
 

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Discussion Starter · #2 ·
Bumping this up?
 

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JVC RS4500 | ST130 G4 135" | MRX 720 | MC303 MC152 | 6.1.4: B&W 802D3, 805D3, 702S2 | 4x15 IB Subs
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I have a home theater PC and when I use the scroll wheel with an internet browser open my DIY subs (approx 20ft away) exhibit a sort of buzz while scrolling. My DIY subs are hooked up to a cleanbox which adds a fairly high analog gain.

It happens both with the graphics card and the on-board HDMI output. I've tried multiple HDMI cables. I also added Ferrite chokers up and down the signal chain with no improvement. I've also tried wireless and wired mice to rule out IR issues.

Oddly enough, it happens with the receiver powered down too (the amp is still on 20ft away). The signal chain is PC to TV to eARC to Reciever to sub out to MiniDSP to Cleanbox to amp to sub. So it happens somewhere between there

Any ideas? I'm completely defeated.
Rather than caused by the mouse scrolling, I'd suggest it's caused by the video card processing the change of picture. It's interesting you've experienced it also with on board video, though. I would expect that to behave differently. It sounds like coil whine transferring into the speakers electrically.

Have you tried putting a blue jeans cable isolating transformer inline on the sub RCA? I think I had to do that when I had the 1080TI coil whine going. Even though it wasn't exactly like a ground loop 60hz hum, it still knocked it out for me.
 
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Discussion Starter · #4 ·
Rather than caused by the mouse scrolling, I'd suggest it's caused by the video card processing the change of picture. It's interesting you've experienced it also with on board video, though. I would expect that to behave differently. It sounds like coil whine transferring into the speakers electrically.

Have you tried putting a blue jeans cable isolating transformer inline on the sub RCA? I think I had to do that when I had the 1080TI coil whine going. Even though it wasn't exactly like a ground loop 60hz hum, it still knocked it out for me.
I'll give that isolation transformer a try. I'm going to try out a different PSU as well. I was surprised the On-board did it too.

I do have an ART Cleanbox but with the high gain, I think that's actually making it audible.
 

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I'll give that isolation transformer a try. I'm going to try out a different PSU as well. I was surprised the On-board did it too.

I do have an ART Cleanbox but with the high gain, I think that's actually making it audible.
I also had a cleanbox pro, and with or without it inline made no difference. Is it an option to turn the output of the cleanbox way down and the gain on the subs, themselves way up? If there's headroom for that, it may help. Please report back on the isolation transformer. That things pretty good. It's the only isolator that I've ever used that didnt also roll off all the bass.
 
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Discussion Starter · #6 ·
I also had a cleanbox pro, and with or without it inline made no difference. Is it an option to turn the output of the cleanbox way down and the gain on the subs, themselves way up? If there's headroom for that, it may help. Please report back on the isolation transformer. That things pretty good. It's the only isolator that I've ever used that didnt also roll off all the bass.
Will do! It should arrive next week. I use the cleanbox for Gain because I have unbalanced coming in and need to switch it to balanced because my Crown XLS2002 really has low gain even on .775. So the cleanbox takes it where I need it to go.

Thanks for tip!
 

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Have you tried connecting the pc to a different power circuit ? Next i would isolate everything in the circuit by powering everything off except the pc and the amps, then introduce the devices one by one into the chain, clean box, minidsp, then tv. How far away is your pc from the minidsp and its power supply? Thats where i think the noise is being injected via the main power from the PC switch mode power supply.
 

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Discussion Starter · #8 ·
Have you tried connecting the pc to a different power circuit ? Next i would isolate everything in the circuit by powering everything off except the pc and the amps, then introduce the devices one by one into the chain, clean box, minidsp, then tv. How far away is your pc from the minidsp and its power supply? Thats where i think the noise is being injected via the main power from the PC switch mode power supply.
That's a good idea. I'll get an extension cord and move the HTPC to a different circuit.

PC is about 15ft from one MIniDSP and about 6 feet from the other. Neither minidsp's share a power strip with the HTPC.
 

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That's a good idea. I'll get an extension cord and move the HTPC to a different circuit.

PC is about 15ft from one MIniDSP and about 6 feet from the other. Neither minidsp's share a power strip with the HTPC.
Another thing to try is to clip the ground plug off the PC power cord or use a cheater plug and see if that helps. If so, there are more permanent ways to fix that.
 

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Discussion Starter · #10 ·
Another thing to try is to clip the ground plug off the PC power cord or use a cheater plug and see if that helps. If so, there are more permanent ways to fix that.
I have a cheater plug. I can give that a try too
 
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