Topic: Phase vs Polarity
From the Totalmix manual:
Phase L. Inverts the phase of the left channel by 180°.
Phase R. Inverts the phase of the right channel by 180°.
The terms "phase reversal" and "phase inversion" are meaningless and incorrect: Phase can be shifted in the time domain, not inverted or reversed. Those switches in Totalmix don't do anything to phase, all they do is reverse the polarity of the incoming signal, which is the same as multiplying by -1. This has nothing to do with the time domain.
Also, talking of a "180° phase shift" is meaningless in the context of a non-periodic audio signal which not only changes over time but is also made up of many different wave components each having different frequencies. Measuring phase shift in degrees is only suitable for the unlikely case of periodic waveforms, that's why oscilloscopes use units of time to measure phase shift.
Perhaps RME could consider using the correct terminology, like this:
Polarity L. Reverses the polarity of the left channel.
Polarity R. Reverses the polarity of the right channel.
Cheers!
Some manufacturers use "polarity reverse switch", some "phase reverse switch"; I've seen both in different manuals. I guess the important thing is we know what the switch really does and when to push it.