[cycomanic]

That's not really the reason. It's important that the concept of phase is not something absolute, it only makes sense in relation to something. Absolute phase could be defined from the beginning of the universe which is nonsensical .

You are right nobody can hear phase, but nobody can see phase either again because you need to relate (interfere) to something. However it does make a difference if we think about the superposition (interference) of different audio frequency components. We would definitely here some of those phase differences.

That said iq does not make sense in audio processing because it's baseband. There is no carrier wave.

[marcan_42]

We do not hear phase differences in the relative phase of different audio frequency components. Try it for yourself. Run a song through an allpass filter. It'll sound the same. In fact, speaker systems of all kinds do crazy things to the phase of signals, and nobody cares (what we care about is frequency and transient response).

The same is not true for radio. There, corrupting the phase relationships corrupts the data (for many systems).

Phase is relative, but our ears don't care about relative phase either (at least as long as you don't stick nonlinear filters after, then it starts mattering, but usually in audio things are fairly decorrelated anyway so it only matters in quite specific cases).

Here is an example: https://twitter.com/marcan42/status/1282685645731672064

Demo: https://twitter.com/zwegner/status/1282859889447116809 (interestingly, you can hear the change in Twitter's low quality encode, but it goes away at higher qualities, so it seems their crappy AAC encoder does care about relative phase :-))

It's counterintuitive how little our ears care about phase across frequency bands. This is not true for other kinds of signals.

[cycomanic]

I just tried this and you're right, complete random phase across the the whole frequency band does not noticeably change things. Funny that we learned that differently. Thanks I learnt something about audio today :).

[h2odragon]

afaik phase only really matters in audio for speaker enclosure design, placement, and likewise microphones.

However, because its virtually unknown to audio folks theres perceptible nodes everywhere, if you can hear them.