[vorbis] what quality ?

Morgan Mörtsell morgan at mortsell.com
Sun Apr 21 22:47:41 PDT 2002

> >
> > Above 4kHz? Shouldn't this be below 4kHz?
> >
> No...well, sort of.
> It's all about the difference between the wavelength
> and the distance betwen our ears.
> High frequencies can be more that 360 degrees out of
> phase with respect ot each other so the information
> is useless for positioning. Similarly, very low frequencies
> are also useless because the difference isn't enough.
> There's only a narrow range of frequencies where the
> phase difference is important for positioning, outside
> that range it's more to do with the volume of sound
> reaching each ear (and remember, there's a nice sound
> absorbing mass in between the ears).
> Working out the frequency of a sound which has a
> wavelength the size of your head is left as an
> exercise for the reader.

<p>Humans have different sensitivity to each frequency in the audible spectrum.
It can be meassured by testing the experienced soundlevel at each frequency,
and plot the result in a graph. Humans are most sensitive about 3500 Hz,
which accidently happens to be where the energy peak of most baby cries lies
too. :-)
This frequency response is meassured in decibel and is called A-weighted
decibel (dBA).

This should not be confused with the ability to sense phaseshift at various

<p><p>/Morgan Mörtsell

"There is always one more bug."  - Lubarsky's Law of Cybernetic Entomology

<p><p>--- >8 ----
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