[music-dsp] Phase sensitivity again

Andy Farnell padawan12 at obiwannabe.co.uk
Fri Oct 8 03:44:08 EDT 2010



It can be useful. Think wider, outside music.
For games/virtual world audio, sometimes a
decorrelation and delocalisation is exactly
what you're after for ambiance (city noise,
rushing of wind in forests, rainfall etc)
A good phase munging could work much better
than a monaural centre pan, which is still
the norm in many game audio engines.

a.



On Fri, 8 Oct 2010 09:30:43 +0200
"Didier Dambrin" <didid at skynet.be> wrote:

> sadly that effect is usually more an annoyance, like in timestretching where 
> it's hard to get rid of
> 
> >
> > I can hear these differences clearly (couldn't hear
> > anything with the previous saw over speakers). Each
> > is processed by a filter or chorus though, which seems
> > to accentuate the phase conditions.
> >
> > Brief first impression: The aligned ones sound focussed
> > like they come from a point, while the randomised ones
> > sound like an uncorrelated extent or volume (ocean waves),
> > kinda as you would expect. Application is possibly for
> > orchestral strings/pads and wind/rain effects to
> > "delocalise" them.
> >
> > Hypothesis: While true that the ear cannot
> > hear different phase arrangements in simply
> > presented static tones, it _can_ make out
> > differences in tones within certain listening
> > contexts. As Sampo identifies this requires a
> > binaural rather than monaural presentation in
> > order for our internal 'decorrelation' brain
> > circuits to work. And as Mike added there
> > are also age/biology differences, as noted
> > by natural 3rd harmonic middle transmission and
> > natural non-linar cochlear structure.
> >
> >
> >
> > a.
> >
> >
> > On Fri, 8 Oct 2010 03:45:43 +0200
> > "Didier Dambrin" <didid at skynet.be> wrote:
> >
> >> Still about phases, I also remember I posted this recently, the only
> >> difference in each pair being the initial phases of the same harmonics, 
> >> all
> >> aligned in the first, all random in the second. Quite useful in a synth.
> >>
> >> http://forum.image-line.com//files/phases2_102.wav
> >>
> >>
> >>
> >> > On 07/10/2010, Didier Dambrin <didid at skynet.be> wrote:
> >> >> there was this one, first is normal saw, I think the second was the 
> >> >> same
> >> >> with the all phases slowly shifted (neighbor harmonic phases still 
> >> >> close
> >> >> enough from each other), and the third shows the 22th (or something,
> >> >> quickly
> >> >> checked in a spectrogram) harmonic with its phase shifted, making it
> >> >> stand
> >> >> out.
> >> >
> >> > Of course, when a harmonic phase shifts slowly over time, it's
> >> > basically the same as saying it's not a perfect harmonic, and our
> >> > brain reinterprets accordingly. This might be why discontinuous
> >> > changes in harmonics are more clearly audible than continuous ones.
> >> >
> >> > (...unless you're me, apparently.)
> >> > --
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> >> > http://music.columbia.edu/cmc/music-dsp
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> >>
> >> --
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> >
> >
> > -- 
> > Andy Farnell <padawan12 at obiwannabe.co.uk>
> > --
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-- 
Andy Farnell <padawan12 at obiwannabe.co.uk>


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