Phase switch affecting sound

[dres]

Hi people,
I have a Focusrite Voicemaster and I've noticed something really perculiar lately. When I simply listen through a mono track through the unit I get significantly different tones depending on the position of the phase switch. I know you'd expect the phase to affect the way *multiple* tracks combine... but a mono track ??

The difference only appears when using the compressor, EQ etc.

Is this normal ? I know I've heard that many instrument waveforms are NOT symetrical... is this the reason for the different tones ?

 

[Ethan Winer]

dres,

> I know I've heard that many instrument waveforms are NOT symetrical... is this the reason for the different tones? <

I don't have an explanation for you, but in tests I've done changing the polarity of normal music is not audible. (If you have a lot of energy lower in frequency than your speakers can reproduce, an audible change might be expected.) So all I can think of is that something else is going on. Why not ask FocusRite about this, and let me know what they say.

And you are 100% correct that a polarity change should affect a stereo track but not mono.

--Ethan

 

[Shailat]

I'll have to support Ethan for once

No way is it possible to hear a phase change in a mono track.

 

[dres]

Problem solved !

Last night I was experiencing this effect again while monitoring through closed headphones and it dawned on me what was happening...

These closed headphones (Sennheiser 270) isolate a lot of sound but of course not everything.... mostly bass frequencies get through from outside. What I was hearing was the sound from the headphones interacting with the bleed from outside the phones. One phase cancels out the bass the other doesn't... nothing wrong with the focusrite after all - Doh !

 

[Dan Kennedy]

I'll disagree with Ethan on this one.

Absolute polarity is audible on some sources.

Not all, but mono vs stereo doesn't
change that.