Internally generated noise in DAW ?

jboy wrote on 4/20/2004, 11:31 AM
I'm trying to do a little home recording using an AMD XP rig on an Epox 8K3A+, (onboard sound disabled), SB Audigy 2 sound card, and am running into the following problem; When I open up either Vegas 4.0 or Cubase SX, I immediately hear what sounds like low level static and noise mixed together-it sounds basicly like the residual noise you hear in a crappy analog amp cranked up too high. I also hear a slight pulsing sound, (@ about 1 BPS intervals), that sounds like some kind of mechanical/electrical device- like a turntable or something similiar. This noise occurs whether I have anything plugged into the input of the sound card or not, and disappears when I close either of the sound related applications. Anybody have any idea whats going on ? Could any of the electrical components in my computer-the fans in particular-be generating a noise that's detected only when I open a sound application ? Anybody have a better idea about where to look for an answer to my problem?-like some other forum perhaps more related to sound alone than the generally sound/video format of the Vegas forum here.I should mention that both of the above mentioned applications function exactly as they should recording sound, only I have this awful baseline noise level when I'm finished. Your input is appreciated.

Comments

Spheris wrote on 4/20/2004, 12:33 PM
What you are experiencing is input EM freq noise. Many DAWS open the inputs on all lines in the selected sound devices, either by design or by accident.

Check the Sound mixer first.mute all and do a spot check record or playback from a fresh capture to track. Then make a note of the inputs enabled when the daw launched and mute them. Relaunch the app and list the inputs being forced open and forward mail to repsctive companies about their apps opening those lines and whether it is by accident or design.

The EM noise is another matter and only fixable by shielding the input assembly by either lead or in some cases laminated foil or other damping shielding material to prevent fan/cpu/pcb trace noise from being picked up by the inputs and outputs which are in extremely close proximity within a standard pc case.
jboy wrote on 4/20/2004, 1:48 PM
Yikes !Thanks Spheris. I'll try closing down open channels tomorrow when I have a bit more time, and then post my results. I'm not that familiar with the terminolgy and modules these applications use, and am having a bit of trouble finding my way around. Hope I don't miss anything. As for the EM, (electrical/mechanical intereference ?), do you happen to know which components are most likely to be putting out such interference , (fans, I would guess)? And if so, are there fans available that are specially designed not to cause this noise ? What do they do in pro work stations ? Do they actually shield the sound card, or are pro sound cards better designed not to pick up these transients ? The card seems real quiet, when it's just being used normally-(such as playing a CD, etc.), so I'm surprised it's noisy when I open a sound app. Tnx for your help..
jboy wrote on 4/21/2004, 10:57 AM
I tried muting everything open in CubaseSX, and I still have the noise. The noise appears when I open any sound related app., including Windows media player. Anybody out there have practical experience with this sort of thing ? I'm willing to try sheilding the sound card, but am not optimistic that it'll work, more than likely the interference is traveling in the circuitry. Tried disconnecting all fans but the power supply and cpu, that didn't make any difference either. Can anybody refer me to a site that'll help me troubleshoot this situation ? I realize it's a bit off topic for the vegas forum, though it is sound related. Anybody know if the motherboard, (epox 8K3A+), might be a factor here ?
zemlin wrote on 4/21/2004, 11:04 AM
It's very possible the only way you'll get rid of the noise is by replacing your sound card with a better quality device (Not creative labs!)