You are here

Digital audio noise from PC

For anything relating to music-making on Windows computers, with lots of FAQs. Moderated by Martin Walker.

Re: Digital audio noise from PC

Postby Marbury » Sun May 24, 2020 11:13 am

I have been putting it off Martin as I know it will take a lot of faffing around which I dread. I was hoping for a quick fix but I promise to read through the article you have kindly suggested. I tend to be a bit lazy about certain things that are mundane (I am working on this flaw of my nature) and just wNt to get on with the creative stuff. If money was no object I would just hire a studio engineer and say I want this, this and this so I can just create. Then again, I have that kind of advice here so its not that bad.
Marbury
Frequent Poster
Posts: 775
Joined: Thu Aug 28, 2003 12:00 am
Location: Cheshire, UK
 

Re: Digital audio noise from PC

Postby Marbury » Tue May 26, 2020 3:17 pm

Well, I have stripped down the Samson servo 170, vacuum out dust, cleaned all connectors with electrical contact cleaner, re wired the Assolute 2 speakers (this time bi-wired) and fired it all up. The sound still cuts out of speakers at low volume (another long standing issue) and usually comes back on if I give the bass cone a tap. The sound itself is ok, better bass but that dam whining is still there BUT it does have quiet moments, unlike before. Unfortunately even touching the wireless mouse or any activity on the pc triggers it back on again. When I unplug the output cables from th K6 to the Samson it stops so the cables picking up this interference seem to be the culprit. However, why can't I hear it through my headphones ? That also in theory should be picking it up as its the exact same audio signal.
Marbury
Frequent Poster
Posts: 775
Joined: Thu Aug 28, 2003 12:00 am
Location: Cheshire, UK
 

Re: Digital audio noise from PC

Postby Hugh Robjohns » Tue May 26, 2020 3:34 pm

Marbury wrote:Well, I have stripped down the Samson servo 170, vacuum out dust, cleaned all connectors with electrical contact cleaner, re wired the Assolute 2 speakers (this time bi-wired) and fired it all up.

Lovely.... but none of that will make the slightest difference to your ground noise issues....

....but that dam whining is still there...

:lolno:

BUT it does have quiet moments, unlike before.

Probably a coincidence, but it might possibly point towards poor but varying ground impedances in the power amp or, more likely, it's mains plug or wall socket (or mains plug-board). It might be worthwhile cleaning the earth pin of the mains plug and trying a different (higher quality mains plug-board).

When I unplug the output cables from th K6 to the Samson it stops so the cables picking up this interference seem to be the culprit.

You're making the classic error of assuming the cables are 'picking up interference', when it's just as likely -- if not more so -- that the ground connection running through the cables is creating the ground-loop we've spent soooooooo long discussing.

One last time: Try inserting an audio isolating transformer box between the K6 and the Samson power amp, OR open the audio cables and cut and isolate the screen connections at the amplifier end (XLR pin 1 or TRS sleeve). Both of these methods break the ground path between amp and interface and thus prevent any circulating noise currents.
User avatar
Hugh Robjohns
Moderator
Posts: 27452
Joined: Fri Jul 25, 2003 12:00 am
Location: Worcestershire, UK
Technical Editor, Sound On Sound

Re: Digital audio noise from PC

Postby Mike Stranks » Tue May 26, 2020 6:38 pm

Marbury:

PM me with your address. I have a 'spare' simple iso-transformer kicking around here that I'm happy to lend you so that you can at least try it to see if it fixes the problem.

You may need to make/purchase some connector cables, but at least it'll be some positive progress or specific elimination of one possible cause of these warbles.
Mike Stranks
Jedi Poster
Posts: 7331
Joined: Fri Jan 03, 2003 1:00 am

Re: Digital audio noise from PC

Postby ef37a » Tue May 26, 2020 7:05 pm

Mike Stranks wrote:Marbury:

PM me with your address. I have a 'spare' simple iso-transformer kicking around here that I'm happy to lend you so that you can at least try it to see if it fixes the problem.

You may need to make/purchase some connector cables, but at least it'll be some positive progress or specific elimination of one possible cause of these warbles.

Nice one Mike. Thinking about it I have a couple of stereo traff boxes kicking about, they are RJ45 in RCA out but since I am pretty sure I have 'it' at the moment nobody will want them anytime soon!

Dave.
ef37a
Jedi Poster
Posts: 11643
Joined: Mon May 29, 2006 12:00 am
Location: northampton uk

Re: Digital audio noise from PC

Postby Mike Stranks » Tue May 26, 2020 8:51 pm

It's one of these; bought for a one-off as I needed an extra iso for a live-gig:

https://www.youtube.com/watch?time_continue=4&v=Ts9ptVsG2Zo&feature=emb_logo
Mike Stranks
Jedi Poster
Posts: 7331
Joined: Fri Jan 03, 2003 1:00 am

Re: Digital audio noise from PC

Postby Marbury » Tue May 26, 2020 8:59 pm

Mike Stranks wrote:It's one of these; bought for a one-off as I needed an extra iso for a live-gig:

https://www.youtube.com/watch?time_continue=4&v=Ts9ptVsG2Zo&feature=emb_logo

Thanks for the kind offer Mike but looking at the Youtube comments from the link you provided, it has made people's noise worse. I can't believe it as I changed the extention block, and it went to almost silent for a good while. Fired up my pc again and it's back to noisy. Why would it do that ? It's an absolute swine of a problem. I am pretty sure it's the wireless mouse and keyboard that is doing it.

I think I will have to concede to buying this gadget on Amazon

Hope you are ok Dave.
Marbury
Frequent Poster
Posts: 775
Joined: Thu Aug 28, 2003 12:00 am
Location: Cheshire, UK
 

Re: Digital audio noise from PC

Postby Hugh Robjohns » Tue May 26, 2020 10:11 pm

Marbury wrote:Thanks for the kind offer Mike but looking at the Youtube comments from the link you provided, it has made people's noise worse.

I can't view that video on the ancient iPad I use for nocturnal forum posts :? But there are 2 potential reasons for an increase in noise when connecting via an isolating transformer. One is that the isolating transformer is placed near a mains transformer, so it picks up magnetic inductions of the mains. And the second is that the original problem noise wasn't caused by a ground-loop (normally because the device is Class-2 or double insulated), and the problem was actually a missing ground reference, instead.

As always, the key to solving problems like these is to correctly analyse, interpret, and understand the problem... and then apply the appropriate fix. There is no simple one-solution-for-all scenarios.

I can't believe it as I changed the extention block, and it went to almost silent for a good while.

More new evidence that points towards less-than-perfect mains earthing arrangements...

It's an absolute swine of a problem.

Ground-loops and earthing often are, especially if the fault finding process lacks rigour and logic.

I am pretty sure it's the wireless mouse and keyboard that is doing it.

If I was a betting man I'd bet my house on them being a symptom rather than the problem.
User avatar
Hugh Robjohns
Moderator
Posts: 27452
Joined: Fri Jul 25, 2003 12:00 am
Location: Worcestershire, UK
Technical Editor, Sound On Sound

Re: Digital audio noise from PC

Postby Martin Walker » Tue May 26, 2020 10:12 pm

Marbury wrote:
Mike Stranks wrote:It's one of these; bought for a one-off as I needed an extra iso for a live-gig:

https://www.youtube.com/watch?time_continue=4&v=Ts9ptVsG2Zo&feature=emb_logo


You're still overthinking this Marbury - ignore those doubters on the TouTube video. That product so kindly offered to you by Mike will work perfectly well if you have a ground loop problem as we all strongly suspect.

You are only suspecting the wireless mouse and keyboard of being the culprits because of the type of background noises you are hearing, and they should all disappear once the ground loop problems are removed :headbang:

Please believe us, as at some time we have all experienced the sort of seemingly random noises you have described, and have subsequently solved them.

Mike bought this product precisely to deal with any that happened during his unpredictable live work.


Martin
User avatar
Martin Walker
Moderator
Posts: 15842
Joined: Wed Jan 13, 2010 9:44 am
Location: Cornwall, UK

Re: Digital audio noise from PC

Postby Mike Stranks » Tue May 26, 2020 10:26 pm

Marbury wrote:
Mike Stranks wrote:It's one of these; bought for a one-off as I needed an extra iso for a live-gig:

https://www.youtube.com/watch?time_continue=4&v=Ts9ptVsG2Zo&feature=emb_logo

Thanks for the kind offer Mike but looking at the Youtube comments from the link you provided, it has made people's noise worse. I can't believe it as I changed the extention block, and it went to almost silent for a good while. Fired up my pc again and it's back to noisy. Why would it do that ? It's an absolute swine of a problem. I am pretty sure it's the wireless mouse and keyboard that is doing it.

I think I will have to concede to buying this gadget on Amazon

Hope you are ok Dave.

Whatever... it is a budget one so I wasn't expecting anything stupendous... but it did the job I needed it to the only time I used it. Anyways... see how you go with the - even cheaper - Amazon one...

Hugh: main point of putting the very short (< 1 min) vid 'up' was principally so that Marbury could see the connectors - TRS jacks. The vid is simply a picture of the iso from various angles with fly-in captions... you haven't missed anything! :)
Mike Stranks
Jedi Poster
Posts: 7331
Joined: Fri Jan 03, 2003 1:00 am

Re: Digital audio noise from PC

Postby Marbury » Wed May 27, 2020 12:07 am

Mike Stranks wrote:
Marbury wrote:
Mike Stranks wrote:It's one of these; bought for a one-off as I needed an extra iso for a live-gig:

https://www.youtube.com/watch?time_continue=4&v=Ts9ptVsG2Zo&feature=emb_logo

Thanks for the kind offer Mike but looking at the Youtube comments from the link you provided, it has made people's noise worse. I can't believe it as I changed the extention block, and it went to almost silent for a good while. Fired up my pc again and it's back to noisy. Why would it do that ? It's an absolute swine of a problem. I am pretty sure it's the wireless mouse and keyboard that is doing it.

I think I will have to concede to buying this gadget on Amazon

Hope you are ok Dave.

Whatever... it is a budget one so I wasn't expecting anything stupendous... but it did the job I needed it to the only time I used it. Anyways... see how you go with the - even cheaper - Amazon one...

Hugh: main point of putting the very short (< 1 min) vid 'up' was principally so that Marbury could see the connectors - TRS jacks. The vid is simply a picture of the iso from various angles with fly-in captions... you haven't missed anything! :)

Mike, I will certainly give it a go (covering your postage) and if it works, I will buy it off you. If not, will return it. Would that be ok ?
Marbury
Frequent Poster
Posts: 775
Joined: Thu Aug 28, 2003 12:00 am
Location: Cheshire, UK
 

Re: Digital audio noise from PC

Postby Mike Stranks » Wed May 27, 2020 8:25 am

Marbury wrote:
Mike, I will certainly give it a go (covering your postage) and if it works, I will buy it off you. If not, will return it. Would that be ok ?

Sorry... offer now closed... I'll keep it as a spare...

But you could always buy one... https://www.gear4music.com/Recording-and-Computers/SubZero-Hum-Destroyer/27BH They do offer a 30-day money-back guarantee so if it doesn't work/it's not up to your requirement you can always send it back.
Mike Stranks
Jedi Poster
Posts: 7331
Joined: Fri Jan 03, 2003 1:00 am

Re: Digital audio noise from PC

Postby Marbury » Wed May 27, 2020 12:21 pm

Fair enough.

The description states though that it is a hum fixer. I wonder if it will tackle digital computer interference noise that I am getting.
Marbury
Frequent Poster
Posts: 775
Joined: Thu Aug 28, 2003 12:00 am
Location: Cheshire, UK
 

Re: Digital audio noise from PC

Postby James Perrett » Wed May 27, 2020 12:29 pm

Marbury wrote:Fair enough.

The description states though that it is a hum fixer. I wonder if it will tackle digital computer interference noise that I am getting.

If Mike suggests that it will work in your situation, I'd take that as a yes. It is worth remembering that Mike, Hugh and a few others here have been dealing with these problems for years so they know what they're talking about and it is worth following their advice.
User avatar
James Perrett
Moderator
Posts: 9315
Joined: Mon Sep 10, 2001 12:00 am
Location: The wilds of Hampshire
JRP Music - Audio Mastering and Restoration. JRP Music Facebook Page

Re: Digital audio noise from PC

Postby Marbury » Wed May 27, 2020 12:37 pm

Ok, will give it a try and report back. It says there is no loss in audio quality. The reason I flagged up the issue with the Youtube comments was because all the the comments were negative.
Marbury
Frequent Poster
Posts: 775
Joined: Thu Aug 28, 2003 12:00 am
Location: Cheshire, UK
 

PreviousNext