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synkrotron

That computer noise thing...

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Posted (edited)

Hi Peeps,

Having finished ensuring all my VST stuff works on my new i9 workstation I am now turning my attention to my hardware.

I now realise that I am plagued by that most annoying and difficult to fix "computer" sound.

This is not a mains hum I am talking about here. It's a digital sort of noise that is almost a constant squeek interspersed with white noise and the odd high frequency crackle. Hard to put into words but I think you know what I mean. Or perhaps you don't, if you have never experienced this yourself over the years. I could record it and upload it somewhere if anyone is interested.

I spent a couple of hours checking all the cables and rearranging them, as best I could, so that audio, mains and data cables do not run parallel at any point.

I have also tried using the same mains socket in the room for everything and I have tried powering just the workstation from its own mains socket. Only thing I haven't tried yet is running an extension lead downstairs, which is on a different ring main to upstairs.

I have done a bit of research on the interwebs and, to be honest, I'm not sure if any of the so called solutions are going to work for me. I found one video and the guy was explaining exactly what my problem was, so I thought, "this is hopeful," but the conclusion was that the socket he was using had no earth and he simply fixed that.

 

Any ideas, anyone?

Ferrite blocks, perhaps? And where would I need to fit these? On just the mains cable or mains + data?

cheers

andy

Edited by synkrotron
removed any stupid suggestions in the original post

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Hello Synkrotron. I have battled this stuff for a long time, I can relate.  A low cost starting point to fix this issue might be the purchase of a few Ebtech Hum eliminator  

plugs....they are really handy and have done the job for me quite a few times.  Definitely a go to device to have in your gig bag too....good luck.

 

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Thanks, @vuzz14,

I have been doing some more tests and I think what I really need is to invest in some balanced cables. I was thinking along those lines anyway and this issue has brought things to a head. I thought I'd be able to save some money using what cables I have from my previous studio endeavours.

 

cheers

andy

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Posted (edited)

It's just "standard practice" to wire any serious studio with high quality cables. Even unbalanced cables will benefit in noise rejection if they are of the higher quality and have proper shielding.   There's not much point in using balanced cables when the connections are unbalanced. Example an audio interface or powered speakers with RCA jacks are clearly not balanced.  And guitar and most hardware synths are never balanced.

RF interference  is not an normally an issue if the cable runs are short. I have all lengths of cables from 3" to 6' just for this reason. I use no more than needed to make my connections. So always start out with the best cabling in your studio. And add to that proper power conditioning for the A/C ( Mains in your speak) . I use a Furman.  

The noise you describe is possibly like the one I will get when I use a wireless mouse.  

I will only hook up my wireless keyboard and mouse when I need remote control while tracking vocals. Otherwise I have eliminated all wireless devices from my studio space.  Even my phone is hardwired.  

And the ferrite chokes are also a great idea especially on you USB cables. There was a thread a few days ago and that person has a Scarlett 2i4 which use buss power. ( EDIT_ I see Mark posted a link above while I was posting) They are documented as making the noise you describe and the ferrite choke is reported to solve that issue. . 

I have a few A/C power cables that have those chokes on them too. 

Edited by Cactus Music
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32 minutes ago, synkrotron said:

I have been doing some more tests and I think what I really need is to invest in some balanced cables.

This is what I was going to suggest. At first I only used balanced cables for microphones, but as I draped cable over cable like a sick game of tick tack toe I realized I needed to upgrade every cable. I did and it has been a lot better. I still cant perfect cable management properly but my only issue now is my Video monitor using Fenders with single coils.

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Posted (edited)

I have something like that and I believe I have it tracked down to the analog cable path from my audio interface outputs to my studio monitors. I should probably be using balanced cables there. Either that or the monitors are picking up the EMI directly.

The noise I hear appears to coincide only with moments  of heavy disk drive usage.

If I disconnect my monitors, I cannot hear the noise using my headphones in the audio coming directly from my audio interface phones jack.  And there is no audible sound coming directly from the computer. In my case that pretty much eliminates ambient noise emanating directly from the PC, or noise in the digital audio signal path.

Edited by abacab
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Another thing to check is digital noise from wireless mice and keyboards. Mice in particular can cause issues in some environments.

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I have the computer in a diffrent room with screen and usb cables going through the wall.  To get rid of irritating high frquency noice from the monitors I had to plug them into non-grounded power socket as they do not have Ground-lift button. Now I have very silent environment.

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3 hours ago, msmcleod said:

Take a look at this recent thread

Thanks, @msmcleod :)

But as @Cactus Music says, those RCA connections are not balanced. I think that while it is possible to connect my active monitors to my audio interface I should try that first.

And in addition to that I knew I had some ferrite blocks somewhere and I managed to find them. When I stuck it on the audio cable between my audio interface and the speaker it didn't make the slightest bit if difference unfortunately, so I am not even sure about bothering going down that route now.

 

Hi John,

3 hours ago, Cactus Music said:

It's just "standard practice" to wire any serious studio with high quality cables.

Yes, I appreciate that. I built my first studio based mainly on hardware some twenty years ago now. When I dismantled it during a "sabbatical" I boxed everything up, including the cables.

Gradually, over the last couple of years, I have been building a new studio. It has gone through many iterations and at the start of 2019 I decided to increase my inputs by adding a second OCTA-CAPTURE unit. Of course, more inputs, more cables, and I have been using stuff I have in stock rather that buying better quality new cables. Back twenty years ago I hardly went onto the internet to discuss or research this sort of stuff and I would go down to my local music store and ask for some good quality audio cables, not even knowing if they were, and not knowing that much at all about balanced cables.

False economy, I know, but I do have a budget and most of my money has been put into other things. So the cables have become my "weakest link." And I suppose I am not a "serious studio" either. I have earned a tad over £100 since I started making music all that long ago so, yeah, just a hobbyist me, with money to burn at times, it seems.

3 hours ago, Cactus Music said:

There's not much point in using balanced cables when the connections are unbalanced.

Yes, I understand that too. I will be endeavouring to use balanced cables where appropriate.

3 hours ago, Cactus Music said:

I have all lengths of cables from 3" to 6'

A good point, and I have cables that are far too long for the distance they have to cover. Again, this is down to me using what I have and then being too lazy to get the snips and a soldering iron. I will definitely be doing this at some point in the near future.

 

3 hours ago, Cactus Music said:

And add to that proper power conditioning for the A/C ( Mains in your speak)

Okay, I have heard this mentioned a few times now so I need to look more into that.

3 hours ago, Cactus Music said:

The noise you describe is possibly like the one I will get when I use a wireless mouse.

Very similar, which is why I say "computer noise" and not mains (a/c) hum.

3 hours ago, Cactus Music said:

I have a few A/C power cables that have those chokes on them too.

I found one before in one of my many boxes of gear and I have now used it to connect my workstation to the mains. Doesn't help, as it happens, but it is there now so might as well stay there.

3 hours ago, Cactus Music said:

I will only hook up my wireless keyboard and mouse when I need remote control while tracking vocals.

Yes, I only have a wired keyboard and mouse and they are both fitted with ferrite chokes.

 

There is more, but I want to post this first and answer some of the other posts above...

 

cheers

andy

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3 hours ago, Chuck E Baby said:

but my only issue now is my Video monitor using Fenders with single coils

Yeah, Chuck, that is one of the things that I have noticed... I also noticed that if I position the guitar at right angles to the video monitor any interference pretty much goes away, and being further away from the video monitor also helps.

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1 hour ago, abacab said:

The noise I hear appears to coincide only with moments  of heavy disk drive usage.

I thought that, too, at first but I have an NVMe OS drive and an SSD so I don't think it is those two. And the drive activity light is quite bright on my workstation and you can see it flashing on the ceiling so you can see that the noise does not coincide with disk activity. But it does sound like that sort of thing.

 

1 hour ago, abacab said:

If I disconnect my monitors, I cannot hear the noise using my headphones

Pretty much the same here. But more of that in a bit...

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1 hour ago, mettelus said:

Another thing to check is digital noise from wireless mice and keyboards. Mice in particular can cause issues in some environments.

Yes, both keyboard and mouse are wired and both have ferrite blocks fitted.

thanks

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33 minutes ago, eyjolfurg said:

I have the computer in a diffrent room with screen and usb cables going through the wall.  To get rid of irritating high frquency noice from the monitors I had to plug them into non-grounded power socket as they do not have Ground-lift button. Now I have very silent environment.

I have experimented with this, and, yes, it certainly does solve the problem, but while I have equipment that is supposed to be grounded I am quite nervous about disconnecting any grounding connections. In this country our residual current breakers rely on that ground to trigger and make the situation safe.

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Both balanced cables and ferrite chokes can help will stop any new noise being introduced into the cable.

What they can't do is remove noise that is already there in the signal.

I've found using a ground isolator transformer stops the noise happening in the first place by stopping any ground loop occurring.

For the sake of $9 / £6 it's well worth trying.

I use one all the time when using my old laptop for sampling. A ground loop occurs when it's powered by the power adapter. On batteries, there's no issue. But batteries won't last the 20 to 30 hours required to sample a whole instrument.

The ground isolator prevents a physical connection between the laptop and the instrument, so no loop can occur.

 

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Okay, here is the absolute latest on this situation.

And I am at a loss...

Around tea time here I gave up, turned everything off and went to have my tea and watched some Six Nations rugby.

Then I went back upstairs to my studio and put everything back together with the intention of perhaps just leaving some items unplugged.

I had noticed in an earlier test that my MPX 500 effects unit was the main culprit. It wasn't causing the noise in the active monitors, that was a separate issue. Instead, it was causing the noise within my DAW and on to the master bus. I found that if I unplugged it from the mains, or unplugged the audio cables then the noise went away.

But I powered up my DAW, prior to unplugging the MPX 500 and, for some strange reason, there was no computer noise on the return track or the master bus. I scratched my head... Waggled a few cables, moved some stuff around behind my little rack and the noise woudn't return. So, like I say, I am at a loss, but obviously happy that there is now no computer noise within my DAW.

However, there is still some noise, but although it is the same type of noise as before it is very quiet.

When I turned on my active monitors there is still an issue here, although, as has been mentioned above, the noise is separate to the noise within the DAW, and even with my OCTA-CAPTURE turned right down the noise is still there. My active monitors do not have a volume control and so they are always at full volume so I guess that helps to make things sound worse.

So until I can get some balanced cables I am going to monitor entirely with my headphones.

I have also noticed that I can get a quieter guitar signal into my DAW by using my MMP-2 mic preamp instead of going directly into the OCTA-CAPTURE. The MMP-2 is connected to the OCTA-CAPTURE via coax SPDIF. I was using it for something else but it makes sense to swap things round a bit.

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8 minutes ago, msmcleod said:

What they can't do is remove noise that is already there in the signal.

Hi again Mark,

There isn't actually any real noise in the signal. I've checked each input by opening an instance of Pro-Q 3, which monitors all the way down to -100dB and all there is is a bit of hiss, which is what I expect to be honest. This computer noise is definitely something "internal" if you know what I mean.

It is worth noting that if I stream anything off the internet or listen to a WAV or MP3 using media player or even using Sound Forge then there is no computer noise, just when using a DAW.

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7 minutes ago, synkrotron said:

Hi again Mark,

There isn't actually any real noise in the signal. I've checked each input by opening an instance of Pro-Q 3, which monitors all the way down to -100dB and all there is is a bit of hiss, which is what I expect to be honest. This computer noise is definitely something "internal" if you know what I mean.

It is worth noting that if I stream anything off the internet or listen to a WAV or MP3 using media player or even using Sound Forge then there is no computer noise, just when using a DAW.

I've got two scenarios:

1. On my laptop, any time I use it plugged into the power adapter, and connect it to an external synth (audio in) or mixer (audio out), the noise appears. Using a ground loop isolator fixes this in both cases.

2. In my studio, "computer activity" noise, like hard disk access, moving the mouse etc, causes a high pitched noise. All my USB cables have ferrite chokes. My whole studio is powered via a fairly expensive inline UPS that generates its own clean sine wave AC power signal. This has almost eliminated any hiss in my signal chain, but the "computer noise" still remains. Again, a ground loop isolator cable between the speakers and the audio interface output cures this.

Here's the wierd thing... if I connect my computer's inbuilt audio device output directly to my Mackie BigKnob's 2nd input, this computer noise is introduced on my main source signal - even though it's not switched to that input. 

I find the noise isn't totally restricted to the DAW, but more related to intensive CPU, USB or disk activity.

But again, a ground loop isolator transformer fixes it.

I totally accept that may be there is a deeper ground issue that may need addressing, but the fact is, the ground loop isolator fixes it.

 

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54 minutes ago, synkrotron said:

I thought that, too, at first but I have an NVMe OS drive and an SSD so I don't think it is those two. And the drive activity light is quite bright on my workstation and you can see it flashing on the ceiling so you can see that the noise does not coincide with disk activity. But it does sound like that sort of thing.

 

Pretty much the same here. But more of that in a bit...

And another possibility I have considered is that the powered monitors are picking up the computer noise via their AC power lines.

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19 hours ago, synkrotron said:

I also noticed that if I position the guitar at right angles to the video monitor any interference pretty much goes away

Same here. My position is 60 degrees left or right of the monitor (which is basically almost having my back to the video monitor:D)

PS- My Fender J-Bass is the same way

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