Phase inversion on audio signal

[mildmanjan]

Hi all, I've looked in the archives but I cant find any way to simply invert the phase of an audio signal. I'm aiming to make a mid/side based processor. Is it possible? have I missed something super obvious? Thanks

[MattilynMattroe]

Hi, math/inv should do what you want

[mildmanjan]

Thanks - when I try that it gives the same image on the scope - is that an issue with the scope rather than math/inv?

[MattilynMattroe]

I think that's the scope. I tried a simple patch inverting some noise and summing it with the original noise and got silence

[mildmanjan]

That'll teach me to trust my eyes for an audio problem thanks!

[Sebo]

The scope triggers on the rising edge of the signal, so you always will see the signal as it were in phase.
I think there is a scope that have a separated trigger input, just trigger both scopes with tthe same signal to see the difference in phase.

[trimardius]

I remember reading something like this before. Maybe this helps, not sure...

Is it possible to make a 3 phase VCO or MIDI controlled oscillator?

A separate trigger inlet on scopes would indeed be useful and not very hard to do. Another way to observe the phase difference is using non-triggered (free running) scope objects, and connecting their freeze input together

[ricard]

You could try with a non-symmetric waveform like a sawtooth, then it should be obvious regardless of how the oscilloscope object triggers that the phase has been inverted.

[SirSickSik]

try out my stackable scope (sss/disp), this has an independent sync trigger input.
Then use only one of the two oscillators to sync both and send the two oscillators to the input pins.
Also got several bigger scopes for bass and k-rate frequency oscillators.