What phase inversion does
Phase inversion multiplies every sample by −1, flipping the waveform upside down. Played alone, an inverted signal sounds identical. Mixed with the original, the two cancel out perfectly (a null test). Mixed with a similar but not identical signal, the difference is what remains.
Use cases
- Speaker polarity verification — mix L vs L-inverted to confirm wiring
- Null-testing two versions of a mix (compare before/after compression)
- Creating mid/side or center-cancelation effects when mixed with stereo source
- Cancellation of unwanted noise that has a clean inverse reference