Adam Atkinson <gh...@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.
