Robin wrote:
> Whereas Philips wanted 32KHz or lower, because their concern was to make =
something cheap and get it out the door. The compromise was 44.1 KHz, as we=
know.
I think the odd sample sample rate of 44.1 was choosen because it matched s=
omehow the modified video recording equipment that has initially been used =
for recording digital audio (http://en.wikipedia.org/wiki/Sampling_rate).
> I also used to be able to hear bats. The sound was most uncomfortable to =
me. In fact, I would not characterise it as a "sound" as such. Maybe others=
with more experience know what I mean.
Yes, one can indeed hear some bat sounds. But that does not mean that we ca=
n hear anything above 20 kHz...
A number of larger bat species that emit echolocation calls whose call freq=
uencies are well below 18 kHz.
What you heard are most likely the so-called social calls that have a commu=
nicative function. The lowest components of these calls are well below 18 k=
Hz in many species, such as in the Common pipistrelle:
http://www.avisoft.com/batcalls/europe/playback/Pipistrellus_pipistrellus_2=
_o.wav
In the above recording, the lowest components show up at 16 kHz, which can =
be heard by most people as long as they are not too old.
Regards,
Raimund
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