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PC sound in signal path

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Re: PC sound in signal path

PostPosted: Sat Aug 17, 2019 10:17 pm
by Leftyjay
CS70 wrote:Hm that sounds a bit like radio frequency noise? Like when in old times, you heard an sms arriving in the amp before it got to the phone?

If the PC emits RF, it could just get into your guitar cable or pickups - and it would make perfect sense that with the PC off you don't hear it.

You could make a quick test leaving the PC on and all in the same position, but disconnected to the 11r - and play the latter as a standalone unit. Try also have someone moving the mouse (is it wirless) or so.

Maybe i wasnt clear on my issue, but as soon as the pc is off and i play through the 11r, the noise goes away. When the pc is working hard (cpu fan works more) it increases the noise. To me, its obvious that the problem is coming from the pc. Is how to get rid of it the problem :)

Re: PC sound in signal path

PostPosted: Sat Aug 17, 2019 10:18 pm
by Wonks
EMGs are pretty damn quiet though and there's a fair amount of noise there.

Have you changed the guitar battery recently? If not, worth trying out a new one, in case reduced voltage is allowing more noise to be picked up.

Re: PC sound in signal path

PostPosted: Sat Aug 17, 2019 10:21 pm
by CS70
Leftyjay wrote:
Maybe i wasnt clear on my issue, but as soon as the pc is off and i play through the 11r, the noise goes away. When the pc is working hard (cpu fan works more) it increases the noise. To me, its obvious that the problem is coming from the pc. Is how to get rid of it the problem :)

Yeah, what I meant is that it may not be a ground loop at all but a strong RF emission from the PC instead (is it self built?). They both would generate noise which might stop with the PC unpowered , but the remedy for the latter is very different than the one for the former.

Re: PC sound in signal path

PostPosted: Sat Aug 17, 2019 10:32 pm
by Leftyjay
CS70 wrote:
Leftyjay wrote:
Maybe i wasnt clear on my issue, but as soon as the pc is off and i play through the 11r, the noise goes away. When the pc is working hard (cpu fan works more) it increases the noise. To me, its obvious that the problem is coming from the pc. Is how to get rid of it the problem :)

Yeah, what I meant is that it may not be a ground loop at all but a strong RF emission from the PC instead (is it self built?). They both would generate noise which might stop with the PC unpowered , but the remedy for the latter is very different than the one for the former.

Self built indeed. I think, if we are going that route, is important to know that both side of the pc is closed with tempered glass (and not steel or something similar). Furthermore, as I'm typing, if I move the mouse around (WIRED mouse), I can hear a variation of the artifact that I hear in the signal. For some reason, the noise gate within BIAS FX2 (or any other VSTs) is blocking that artifact if I'm playing with my headphones, but will go through the Atomic, even with all VSTs closed.

Re: PC sound in signal path

PostPosted: Sat Aug 17, 2019 10:49 pm
by James Perrett
Leftyjay wrote:Self built indeed. I think, if we are going that route, is important to know that both side of the pc is closed with tempered glass (and not steel or something similar).

It may look pretty but that certainly isn't going to help create a noise free studio. You need a decent metal enclosure all around with all the panels properly grounded so that no electromagnetic fields can leak out. A large expanse of glass on either side is likely to let all kinds of nasty signals out into the studio.

Re: PC sound in signal path

PostPosted: Sat Aug 17, 2019 10:54 pm
by Leftyjay
James Perrett wrote:
Leftyjay wrote:Self built indeed. I think, if we are going that route, is important to know that both side of the pc is closed with tempered glass (and not steel or something similar).

It may look pretty but that certainly isn't going to help create a noise free studio. You need a decent metal enclosure all around with all the panels properly grounded so that no electromagnetic fields can leak out. A large expanse of glass on either side is likely to let all kinds of nasty signals out into the studio.

Yeah, I realized that once the part was ordered and all.

Fyi, heres the noise withtout the pc in the equation (pc off completly, sound was coming from the 11r amp sim, although im not playing in the video). Btw, it was a different guitar (i have more than a few :) ).

https://youtu.be/g_HVrGKi8QE.

We dont here that wierd noise, as expected. BUT, theres a fair amount of noise nonethless. Like I have 2 different issues...

About the panels : should I consider changing the case or I can "patch it"? I dont care it looks like shit honestly

Re: PC sound in signal path

PostPosted: Sat Aug 17, 2019 11:44 pm
by CS70
Leftyjay wrote:
Self built indeed. I think, if we are going that route, is important to know that both side of the pc is closed with tempered glass (and not steel or something similar). Furthermore, as I'm typing, if I move the mouse around (WIRED mouse), I can hear a variation of the artifact that I hear in the signal. For some reason, the noise gate within BIAS FX2 (or any other VSTs) is blocking that artifact if I'm playing with my headphones, but will go through the Atomic, even with all VSTs closed.

Hm then, there you have it. I'm not an expert but in my pc building period (admittedly quite some time ago) I've seen this a few times. Something is emitting electromagnetic interference from your brand new PC and your guitar, cable or whatever is acting as an antenna.

It can be a number of things: from something as simple as the screen connector (once I found it was a VGA port) to any of the internal components.

Since a Faraday cage stops the RF, you can test this by (don't laugh) covering it with plastic and aluminium foil - google it. Not a long term solution (at least aesthetically) but it will confirm or not if that is the issue.

If it is, you've got to painstakingly debug what part is creating the problem.. hopefully it's not the sum of the parts that does (CE RF certification is based on individual components but unfortunately its not necessarily so that the together they comply).

Re: PC sound in signal path

PostPosted: Sat Aug 17, 2019 11:47 pm
by CS70
Leftyjay wrote:
Fyi, heres the noise withtout the pc in the equation (pc off completly, sound was coming from the 11r amp sim, although im not playing in the video). Btw, it was a different guitar (i have more than a few :) ).

https://youtu.be/g_HVrGKi8QE.

We dont here that wierd noise, as expected. BUT, theres a fair amount of noise nonethless. Like I have 2 different issues...

That sounds like more RF, only constant. Typically a lamp, a neon tube or other device. Even the little lights in extension cords rocket switches can create that. Does the sound change if you move about - especially if you rotate on your axis?

Re: PC sound in signal path

PostPosted: Sun Aug 18, 2019 12:44 am
by Leftyjay
CS70 wrote:
Leftyjay wrote:
Self built indeed. I think, if we are going that route, is important to know that both side of the pc is closed with tempered glass (and not steel or something similar). Furthermore, as I'm typing, if I move the mouse around (WIRED mouse), I can hear a variation of the artifact that I hear in the signal. For some reason, the noise gate within BIAS FX2 (or any other VSTs) is blocking that artifact if I'm playing with my headphones, but will go through the Atomic, even with all VSTs closed.

Hm then, there you have it. I'm not an expert but in my pc building period (admittedly quite some time ago) I've seen this a few times. Something is emitting electromagnetic interference from your brand new PC and your guitar, cable or whatever is acting as an antenna.

It can be a number of things: from something as simple as the screen connector (once I found it was a VGA port) to any of the internal components.

Since a Faraday cage stops the RF, you can test this by (don't laugh) covering it with plastic and aluminium foil - google it. Not a long term solution (at least aesthetically) but it will confirm or not if that is the issue.

If it is, you've got to painstakingly debug what part is creating the problem.. hopefully it's not the sum of the parts that does (CE RF certification is based on individual components but unfortunately its not necessarily so that the together they comply).

Ill try the aluminium trick.

Re: PC sound in signal path

PostPosted: Sun Aug 18, 2019 12:45 am
by Leftyjay
CS70 wrote:
Leftyjay wrote:
Fyi, heres the noise withtout the pc in the equation (pc off completly, sound was coming from the 11r amp sim, although im not playing in the video). Btw, it was a different guitar (i have more than a few :) ).

https://youtu.be/g_HVrGKi8QE.

We dont here that wierd noise, as expected. BUT, theres a fair amount of noise nonethless. Like I have 2 different issues...

That sounds like more RF, only constant. Typically a lamp, a neon tube or other device. Even the little lights in extension cords rocket switches can create that. Does the sound change if you move about - especially if you rotate on your axis?

I tried turning and moving, it does sometimes affect how I here that sound, but its not consistent.

Re: PC sound in signal path

PostPosted: Sun Aug 18, 2019 12:54 am
by Leftyjay
Update : Although I still hear the anyoing PC sound when playing with my headphones, it is MUCH LESS noticeable, even with the noise gate of, to a point where I can live with it (until I'm ready to do some serious tracking).

Re: PC sound in signal path

PostPosted: Sun Aug 18, 2019 9:39 am
by CS70
Great to hear. Since moving about has changed things, it can be that it was not so much the pc emitting too much RF but some other component (typically cabling, soldering) which is not shielded enough and acts as an antenna. Jacks etc would typically change their position a bit and change these receiving properties..

The fact that the sound change when you move seem to confirm it's EM interference.

Re: PC sound in signal path

PostPosted: Sun Aug 18, 2019 10:28 am
by Wonks
Can you try a long guitar lead and a headphone extension cable and play in a different room to the PC to get as far away from the PC as possible?

EMGs will happily drive a longer guitar lead without treble loss, so you should then be able to tell if it's definitely the guitar itself picking up the noise, or else it's another component like the lead.

Re: PC sound in signal path

PostPosted: Sun Aug 18, 2019 12:38 pm
by Leftyjay
Theres 2 types of interferance going on here :

In the first video, you hear both : the digital, almost morse codish sound. That sound remains constant, wether i move or not.

In the second video, that interference will get amplified if I move at a certain angle.


Thanks for your replies guys, super helpful. I guess I have some homework to do. Ill try a few things next week and report back ! I realized late yesterday that i could try the same setup with a different pc, my old laptop

Re: PC sound in signal path

PostPosted: Sun Aug 18, 2019 12:39 pm
by Leftyjay
Wonks wrote:
EMGs will happily drive a longer guitar lead without treble loss, so you should then be able to tell if it's definitely the guitar itself picking up the noise, or else it's another component like the lead.

Remember that those sounds can be heard even without a guitar plugged in