Re-Amping Tracks in Logic has me Worried - Defying Laws of Physics?

This case seems to me as the typical example of "Random recording offset" issue, which is caused by bug in apple's OSX firewire driver. The "Randomness" means, that offset value changes everytime the audio driver gets restarted. It shouldn't differ if you only quit and restart Logic - but - one never knows.

Over-man, I am not surprised at all by the fact, that your re-amped track is earlier. Yes, it looks like we have to redefine the phisics laws 😉 I have the same behaviour with my Yamaha hardware and Yamaha hardware uses the IEC61883-6 buggy streaming in the Apple FireWire Audio driver. What I am surprised of: I thought that M-Audio writes their own drivers like Motu or RME or Digidesign. Companies like Apogee, Yamaha, Focusrite, Alesis (?) and others are not writing their own firewire drivers and users of their FW Audio equipement are suffering from the horrible issue.

As many Apogge Enssemble owners noticed this problem sooner or later after they recieved their product, apple released a Beta driver for them which contained some repairs in OSX fw driver. But after some tests were done it was clear. that the offset values get much smaller BUT the randomness is still present 😟

The info in the Leopard SDK version that was seeded to developers a few days ago says, that some Core Audio issues were repaired. I know nothing more so one can only pray for a light at the end of the tunnel...

Some users of Yamaha audio equipement created a petition "Save mLan on Mac". The goal of the petition was to put pressure on Yamaha to put pressure on apple to fix the fw driver - which would help all fw Audio users on Mac. Mlan users finally get response from Yamaha just before NAMM, that Yamaha will take care and will develop their own firewire drivers for their FW Audio devices. I don't know if it can be translated as that Yamaha doesn't believe that Apple will ever fix their fw driver... I rather end this as I do not want this post to be deleted, but I am afraid it will, as almost every post about this horrible streaming bug was...

Speaking generally, a difference of anything greater than zero samples will cause problems if you decide to combine the re-amped signal with the originals at any point. It will cause a partial cancellation (or reinforcement) dependent on the phase of your re-amped signal with respect to the original.

Such comb filtering may even manifest itself if the timing between the two files was exactly perfectly perfect (due to differences in frequency response and other factors), but still, you'll always be better served if the original and re-amped sounds are perfectly in phase, accurate to the sample in this case.

A 1 ms difference is timing/placement can be significant for other reasons. When it comes to quantized drum parts, that small amount can totally throw off a groove.

But don't drive yourself nuts. Considering the flakiness of the FW driver situation, I'd say that if something sounds a little out-of-kilter address it. You'll know even without listening critically if something feels out of time at some point, even by that measly 1 ms. And then again, maybe it won't.

-=iS=-