weird speed/sync with ADAT

  • Thread starter Thread starter fatorangecat
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fatorangecat

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I'm trying to backup 8 tracks of music originally recorded on a 1st generation ADAT recorded to my computer. I'm using the ADAT's optical digital output to connect to an EchoAudio Gina24 and doing the actual recording using CoolEditPro.

I get the audio to my win98 pc fine, but it only plays back at the proper speed when the ADAT is on and connected to the Gina24. If the ADAT is off, it comes out of the computer really really slow.

Might this have to do with using different bit rates? I'm recording it at 32bit, but it's on the ADAT as 16bit (i think) and the max resolution of the gina is 24bit...

anyone else encountered this?

thanks for any help.
 
A clarification...

First off, don't waste your time with that 32 bit BS! Smoke and mirrors that make your audio files uncapatable with other software. Record to the highest resolution of your soundcard. 24 bit fixed is every bit as good as 32 bit floating bit.

Your computer is having to slave it's Word Clock from the ADAT's since the ADAT is the originating machine for the audio. Basically, the word clock is syncing the actual samples of the two devices so that sample one coming from one machine is actually sample one on the machine it is getting transferred to.

What is happening is that you have your soundcard set to external sync for it's word clock. Once you turn the ADAT off, there is no clock available for the soundcard to sync to, but it is trying anyway, thus, your slow playback speed.

What you need to do is put your soundcard in Internal Sync Mode, and your problems will go away.

Make sure also that you are recording at the proper sampling rate. ADAT's record at 48KHz sampling rate by default, so you have to make sure that your software is recording at 48KHz sampling rate too.

You only need to have the soundcard syncing it's word clock to an external source when you are actually doing transfers back and forth (or course, you could have the ADAT syncing to the computers word clock, but that would require the BRC to do that....). Once you are done transferring, switch back to internal sync mode.

Good luck.

Ed
 
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