arconaut wrote on Thu, 13 January 2011 17:45 |
One more - this is recording into PT while using Logic and iTunes for source playback. Again, polarity is ok.
So the issue seems to be on input. But still, we don't really know if the issue is with Logic or with CoreAudio. For this, we'd need to eliminate CoreAudio.
But that's all the time I can dedicate to this for now!
Noah
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Hi Noah, thanks again for your thorough test.
I can confirm the result.
I imported the sine wave from my test into I-tunes on a second Mac.
1. I recorded the output from the second Mac into Pro Tools on my Studio Mac and the polarity stayed intact.
2. I recorded the output from the second Mac into Logic ( with Digi Core) and the
polarity was switched.
You are right. The polarity Switch happens on the way in.
I asked some friend to perform the same test with a Logic/Symphony system.
3. Christoph played a sine wave from Logic trough the Symphony system with Apogee 16x DA converters and recorded it back into Logic with Apogee 16x AD.
The polarity stayed intact.
4. Then he imported the sine wave into I-Tunes and played it back through the onboard Apple analogue output.
He recorded it back into Logic through the Apogee 16x AD and.......
The polarity was switched!!!!
That means that with Christoph's Logic/Symphony setup the polarity is switched on the way in.
But it also means that the polarity is again switched on the way out!!!!!!
It seems to switch polarity twice.
That means that everything he records will be polarity reversed when being played back on a Pro Tools system.
That might be one of the reasons why a mix played back with Logic/ Symphony can sound different when played back with I-Tunes through the same converters.
I have asked another friend to perform the test with another sound-card and Logic.