1 (edited by tacit 2012-08-11 02:08:18)

Topic: Phasing with Two Fireface 800s

Hi All,

I am running two Fireface 800s configured as an aggregate device in osx.  They are linked in a master slave configuration via a Coax cable. They're channeled into a 16 channel analog mixer.  In my DAW setup, I run a software compressor stereo send channel for drums and that compressed signal runs into two dedicated channels on the mixer. I do this for parallel compression and it looks like:

Mixer Channels 1/2 -> Untreated drums
Mixer Channels 3/4 -> Compressed drums

Here's my problem: 

If I use two channels for compression from the same Fireface 800 that the untreated drums are on, then the parallel compression works fine and everything is in phase.  However, when I am using two channels from my second Fireface, there is phasing on the compressed channel.  Does anyone know how I can fix this?

Thanks!

Re: Phasing with Two Fireface 800s

I just managed to solve this one.  In the audio/midi setup for the aggregate device in OSX, you have to disable software drift correction for both devices (since the Fireface's are synced at the driver level via the coax cable I'm assuming).

3

Re: Phasing with Two Fireface 800s

That is correct. The internal drift correction (basically a sample rate conversion) is not needed when the units are clocked correctly. That saves both CPU and latency.

Regards
Matthias Carstens
RME