Re: Cellphones and Audio (was Ghost Click, though I got no idea why)

[Robert Bonomi <bonomi () mail r-bonomi com>]

Adam Atkinson <ghira () mistral co uk> wrote;
> Jay Ashworth wrote:
> > Now, those codecs *are* specially tuned for spoken word -- if you try
> > to stuff music down them, it's not gonna work very well at all...
>
> It was claimed to me many years ago that the 4kHz cutoff used in POTS 
> serves women and children less well than it does adult males. I have
> never been aware that I have any greater problems understanding women or 
> children on the phone than I do men, but my hearing is not great. I 
> can't hear the difference between G.711 and G.729, for example, but some 
> people can.
>
> Googling "PCM adult male voice", "4kHz adult male" and similar isn't 
> finding me anything. Was I told nonsense?


Probably.  "sort of."  <grin>

'Way back when', at least in the U.S., the 'voice' passband was 300-3000Hz. 
Later, 300-3300Hz.

For perspective, rf you know anything about music, the 'A' below "Middle C' 
is nominally 440Hz.  300Hz is roughly an octave below Middle C, and 3kHz is
2-1/2 octaves above it.  That's the -high- end of the range for a piccolo, 
or coloratura Soprano.  Now, absent the overtones that give a note it's 
'color', one of those high-pitch sources will sound more than a little bit 
'tinny' over a classical 'voice passband' channel.

*HOWEVER*, the 'fundamental' frequencies for womens/childrens voices -is-
higher than that of adult males.  But you're talking less than an octave
in 'most' cases.  Less than 2 in 'extreme' (a guy with a _deep- bass voice
-- "basso profundo", and a 'squeaky' female/child) cases.  This mean that
one does lose one to two additional 'overtones' of the fundamental on 
women/children, vs.  men. 

This does, in general, *NOT* materially affect the 'intelligibility' of
the voice, although it does have a measurable adverse effect on the 
'identifiability' of one such higher-pitched voice vis-a-vis a different
similarly-pitched voice.  You lose more of the 'color' of their voices
vs the lower-pitched male voice.