hiss in digital tracks

tureg wrote on 8/26/2003, 2:10 PM

i have a minidisc connected to an iMic (analog to digital convertor) which goes into the USB port of my PC (win 2000). I have been noticing that when I hit the record on the audio track (without any audio input) the decibel meter starts to move. I have tried moving the connection to various USB ports and I still pick up this 'bkground audio', though the levels vary with the port. I tried connecting thru my sound card and I still picked up this 'bkground audio.' I am a bit on a) why i am picking up this sound thru the USB+digital signal, b) what is the origin and c) how do I get rid of it?

Thanks

Tureg

Comments

Chienworks wrote on 8/26/2003, 2:53 PM

Well ...

a) Your signal isn't digital all the way through. You have a D/A conversion at the output of the minidisc player and an A/D conversion at the iMic. This analog step is probably the source of the noise.

b) See a.

c) Unless your minidisc player has a direct digital output there's not much you can do about it. Using a substantially better A/D converter would help some, but would probably cost a lot more and not make that huge a difference. Try playing with Parametric EQ and see if you can eliminate the few frequency ranges that are rich in hiss. If you set the bands narrow enough you shouldn't affect the signal much. Also take a look at SonicFoundry's Noise Reduction plugin which does a very nice job with this sort of problem.

tureg wrote on 8/26/2003, 3:31 PM

thanks. i also get the hiss when i connect directly to my sound card. I was wondering if it be from my PC?

Chienworks wrote on 8/26/2003, 6:31 PM

Quite possible. Most consumer-grade sound cards are very noisy.

Geoff_Wood wrote on 8/27/2003, 3:05 PM

Not 'from your PC' so much as specifically 'from your soundcard'. You may be interested getting a better quality one than'generic'. There is a range of good quality at moderate price ones around, including the TB Sanata Cruz and the SoundTrax (Hoontech) range.

geoff