recording interference - hum of HD and CD-ROM

acha11

New member
hi all,
my problem is this: whenever i record OR play music from my computer while another electrical device is attached (eg. guitar amp lined out into the back of the sound card to record), somehow the hum of the hard drive and cd-rom and other weird stuff i presume is inside the computer gets added to what i record. it's a very, very obnoxious, metallic hum, and it's just loud enough to irritate even when you're not really concentrating on it.

if, say, i'm recording using cakewalk, and press alt-tab to bring up another application fullscreen, i can hear the hum of (i presume) the video card working hard to update its framebuffer. or if i start up explorer and double click the cd-rom icon, i can hear the cd-rom spinning up and then down. very bizarre.

anyway, i don't _think_ it's a ground loop thing, because this happens even when the computer and the attached device (be it a set of powered output speakers or my amplifier for recording) are plugged into the same outlet. please correct me if this has no bearing whatsoever on the problem [grin].

i've tested with two different soundcards in my computer, and the problem persists.

i've used three different amplifiers, and the problem persists.

i've used two different stereos and the problem persists.

when i use headphones instead of powered speakers, there's no problem (so long as the guitar amplifier isn't connected to the sound card's line in).

when i run my guitar direct into the sound-card's line-in, there's no problem (so long as i haven't got the sound card running out into a separate electrical device).

does _anyone_ have _any_ idea what's going on here? please?

chalmers
 
This is a long shot.

I use to use turtle beach multisound pinnacle to record with. I would always get this persitant high pitched hum in whatever I recorded. Not super loud, but enough to be very annoying. Anyway, after messing around with different configurations of hardware, cables etc.. I narrowed it down to the computer power supply. Put a new one in, an 'poof', no more annoying noise.

As I said, this is is a long shot, but if all else you try fails...

It does sound more like grounding problem though.

Good luck.



[This message has been edited by Emeric (edited 05-24-2000).]
 
I have to ask the annoying question.

What two soundcards did you try?

Sounds very much like a soundcard issue. Also make sure that you've muted everything but Wave and Line In via the soundcard's Recording and Playback controls. The CD input is especially noisy.

Slackmaster 2000
 
the CD is noisy as hell...dont have that problem since my CD is attached through a digital interface......i did find though that my hard drive had been set to DMA mode once, and i would get noise that seemed to coincide with the hard drive turning, anyway i unchecked DMA in control panel/system......and the problem stopped. dont know if that will help any but.....good luck,

Joe
 
Just your luck.

I had that exact same problem before, so normally I'd be able to help you.

Although, Murphy's Law always works: I can't remember what was wrong.

But I think slackmaster's right. I think it's the soundcard.
 
I had a simular problem with noise. But it all went away after I started plugging all of my gear into a power strip that was plugged in to an APC U.P.S. Your problem may just be a difference in ground potential between your amp and computer or your amp may be using trying to use more power than what is available. A uninteruptable power supply might just be your simplest answer and maybe your cheapest. It's also good protection for your gear during a storm.

Hope this helps

GRIZ
 
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