Audibilty of Phase

[a k butler]

I'm surprised not to hear this mentioned so far:-

"A change of phase is inaudible as long as the phase change is
linear across the whole frequency spectrum, otherwise it's audible".

Isn't that the ideal that loudspeaker manufacturers aspire too?


Please don't think I'm pretending to be wiser than the experts
tho', just passing on stuff I've heard for the interest of it.

andy butler (aged 48)

ps. I did the 1st listening test too, at first I heard
no difference except that the middle tone seemed
very slightly louder,
but when I turned an ear towards the speaker, the rogue
tone was very clearly audible.
Having heard it once, it was then easier to pick out.


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[Didier Dambrin]

Well I wrote something like that already.

First, a phase change of the same amount for all harmonics should be totally
inaudible. I'm using this in my audio editor (edison) to normalize short
samples a little higher. I just phase shift everything slightly until I get
the lowest peaks. So you can really end up with short hits louder than by
standard normalization, with no audible change.

Second, I believe you can change the phase progressively up the spectrum,
it's only the abruptness that matters. In my first test, for the second
sample (the one that sounds the same), I'm progressively dephasing each
harmonic, so that the last one has wrapped 3x.  If the phase difference
between 2 neighbor harmonics isn't too big, I don't think it will be
audible.
I think it's pretty much the same for phase & amplitude. If you take a sound
& chop it above 2khz with the most abrupt lowpass, it should be ringing at
2khz.

> I'm surprised not to hear this mentioned so far:-
>
> "A change of phase is inaudible as long as the phase change is
> linear across the whole frequency spectrum, otherwise it's audible".
>
> Isn't that the ideal that loudspeaker manufacturers aspire too?
>
>
> Please don't think I'm pretending to be wiser than the experts
> tho', just passing on stuff I've heard for the interest of it.
>
> andy butler (aged 48)
>
> ps. I did the 1st listening test too, at first I heard
> no difference except that the middle tone seemed
> very slightly louder,
> but when I turned an ear towards the speaker, the rogue
> tone was very clearly audible.
> Having heard it once, it was then easier to pick out.
>
>

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