HD9 Core Audio Mix Bus Sound Issues

[r_w_breen]

Hi All,

Thanks to the Core Audio support I'm able to use HD9 now at home on the oldest Intel Mac Mini possible... all things considered it's really stable and screaming. M-Powered didn't run this well on it and I'm REALLY thrilled... BUT:

When I record a mix off an Analog Desk into 2 channels to HD 9 on this rig and export it out directly it sounds better than taking that SAME 2ch mix, then rerecording it via Pro Tools buses at unity to 2 separate channels and then bouncing THAT out. I tried this when mixing in a stem later in the track, but the whole thing sounded worse, even when the other stem wasn't playing.

In theory nothing is happening here when the main track is playing through the PT bus but a straight copy.

Yet the LF gets mushy, the top is a little more closed in... it just doesn't sound as good. When I've done this same manouvre on an HD rig at work (with core card and interfaces) it sounded a whole lot more like a straight copy with no change in the sound.

So I'm wondering... does HD offload the heavy lifting (upsampling, whatever it is) for a mix onto the core card? Does the math differ in any way when you use HD9 and don't have a core card?

I swear I hear it.

Anyone else experience this?

Still think the software is marvellous, but this would mean I can't recombine stems off a desk at unity in PT using coreAudio without compromising quality.

Help?

Thanks!
Bob

[Tweakhead]

Originally Posted by r_w_breen

I swear I hear it.

Do a phase inversion test of the two mixes, and let us know the results.

[r_w_breen]

Duh... of course. Should have done that before posting. :P

I'll do it when I get home.

I should add though, it wasn't subtle. Wasn't horrendous, but it wasn't subtle. You'd want to send the better one to mastering...

[r_w_breen]

Did the phase test... obviously I was hearing something I did unintentionally in the export stage, because they totally cancelled.

I did a couple tests, one with a straight copy of a mix, another with an instrumental plus a vocal stem mixed in, both mixes cancelled completely when one was inverted.

Chalk this one up to human error. I'm relieved!

Bob

[Tweakhead]

Good to know that it's ok !