Hearing things: computer and mouse noises through speakers and headphones

Hi all, 
I am hearing very low level (but none the less maddening) noises from inside my computer coming through both speakers and headphones. The noises seem to be related to the computer "thinking", drawing windows, accessing discs and, most noticeably and reproducibly, mouse movement which causes a zipper like sound.
 
I have found a few similar references in searching "computer noise", "mouse noise", etc., but none of the situations seems quite exactly like mine. In particular, I would say that this is NOT the sound associated with "computer whine" and not I don't think it seems necessarily related to the video card but I could be wrong.
 
I have replaced the power supply and the main fan. I thought for a long time that it may be related to my firewire interface with a non TI chipset on MOBO. I put in a dedicated TI card and still had problem. Eventually I upgraded my audio interface from m-audio 410 to a Roland Octacapture (USB) and the problem persists. I know that this is not a Sonar issue because it is present when Sonar is shut down and I just have the computer on without even having a stand alone VSTi running. If the computer is off and I play keyboard (Kurz PC3X) thru the Octacapture stand alone the sound disappears (duh!) so I know for sure it is coming "from" the computer.Interestingly, but probably not surprising, the sound will disappear if I use the digital outs on the Octacapture to feed my monitors (JBL 4328's).
 
The computer is a 2 year old Dell with i7, 3 hard drives (1 is eSATA - no diff if that is disconneccted), video card is a 1Gb nVidea running two 24" monitors in HD, Windows 7 (aero is on). Avast anti-virus (makes no diff if turned off).
 
Hoping to find any ideas or advice. I am loathe to swap vid card only to find that is not the culprit but I will if I have too. Is there any way in BIOS to bypass the vid card? I think the MOBO has intel video chipset but not entirely sure about that.
 
Brian
 
 

Since using the digital outs to your monitors cures the problem I'd guess that your speaker cables are picking up electrical interference from the computer.

Check that the speaker cables are routed as far away as possible from the computer cables (eg video monitor cables) or maybe invest in some speaker cables with better shielding.

Sounds like RF interference. There are a couple of things you can do. First - make sure your computer is grounded. Secondly - make sure the monitor cables have a rf damping "block" (and -if possible- the cables connecting to the USB and Firewire too). You can also use a rf blocking device in the power cables, but I think this wont work, because it is not external rf related. Third - make sure your computer power supply is giving enough output to feed all hardware. Some "cheap" power supply's are not up to par and can give this problems. At last - there could be a problem with the motherboard design. Some computers are great for gaming or office use, but not for music.

I was getting those noises when using the usb interface for my midi guitar setup, so I used the legacy midi and no problem.
There was a cure, like adding a ground wire or something but I never used it.

So you might try unplugging usb cables.

I notice I get the same thing when I plug in my usb player to load songs on it and it shares the sound system with the computer.

Swamptooth,
I had never even seen those damping blocks until I bought a new home theater amp a few months ago. I've never had an RF problem that I noticed before. Do they really do much?

I had this issue when connecting my audio interface to an external power amp. I put a device, such as the  Behringer Micro HD400, in between my audio interface and the power amp and that solved the problem for me.

It's Halloween isn't it?

Well I made it to GC tonite and picked up some TRS-XLR cables but they have made zero difference. I did buy the $12 Hosa cables instead of teh $45! Mogamis. Not sure if that makes a difference or not. Craig Anderton suggested grounding the octa to the computer. I hadn't even noticed that there was a grounding screw on the back before. I just did that and, after trying a few different spots on the computer chassis, it definitely does make a significant improvement. I can still hear the noise but it is probably reduced by about 60-75%. Funny, I thought that when I finally hit upon the solution it would totally fix the problem. Either I need to find a better grounding site or look for other causes of interference.

Good idea. I am wondering if my house ground isn't a bit sketchy!

I'm curious... do you have a power filtering power strip or UPS or are you plugged directly into the wall? If you are plugged directly into the wall I highly recommend at the very least getting a high quality surge protecting/power filtering power strip but if you have the dough a good uninterruptable power supply (with surge protection and filters) is even better. It may not solve all your problems and you should still get your house wiring checked (if things aren't grounded properly it's against code and a fire hazard as well as being potentially catastrophic for you gear) but they are worth it for the peace of mind alone. The good ones come with insurance for the equipment hooked up to it.

I picked up a nice Belkin power strip from Amazon for pretty cheap ($30 IIRC) which has $10,000 equipment insurance. Still gotta get a UPS but they are much pricier and weigh so much the shipping costs are prohibitive so until I can get my sorry arse to a proper computer store it ain't gonna happen.

Also I had a lot of noise problems until I picked up some balanced monitor cable but it seems you've already covered that. Cheers.

I am making progress! I have discovered that the problem is ONLY pesent when I have audio cables plugged into the Kurzweil (and octa, of course). Interestingly (to me) the Kurweil does not even have to be powered on for noises to appear at the monitors. If I unplug the audio cables from the Kurz - SILENCE! - even if I have Dim Pro running and using my Remote SL for midi input. Therefore, I have to conclude that the audio cables from the Kurz are acting like antennae for RF interference. I have tried every audio cable in my arsenal (nearly all are unbalanced but there was one short pair of balanced cables). Some are better than others, none are perfect. The balanced cables I thought might be the solution but they are no better than average. That said, they are probably pretty cheap balanced cables. I really don't even know what I ever bought them for. So, unless someone has a better suggestion, my next step will be to get some decent balanced cables and see what happens! Once again, thanks for all of the suggestions!

I think you just have dirty power coming from your wall outlets. A proper USP that filters the power is your best bet if you can't get an electrician in to check things out.

You should NOT be getting that much noise... period. Good luck.

Powering down the Kurz doesn't really make any difference. Unplugging the Kurz quiets things down a little bit. Thinking that the Kirz might be the whole problem. Possible that there is some sort of ground issue with the Kurz that is causing all this. The noises are definitely coming from the computer (moving the mouse makes an obvious zipper sound, the rest is sort of a rythmic chick-chicka-chick kinda sound) but the are only there when the audio cables are touching the outputs of the kurzweil. BTW, I know it isn't the Octa because I had the same problem with my old m-audio 410. FWIW, the system is all plugged into a Furman rack rider power conditioner - I don't know if that makes any difference at all in terms of power quality.