Re: Surround Sound Recording - bats

[madl74]

> Pro Tools has a convenient key combination shift-spacebar to play at 1/2 =
speed.

Dan,

If you add another zero to the price of a bat detector, they downshift,
usually to 1/10 speed between calls. There are other cheaper detectors whic=
h
sample and discard 9 out of 10 samples which is not as good, but work in
real time.

What a heterodyne detector does by an arithmetic downshift is to extend the=

apparent frequency variation which is very useful with several genera of
bats with a CF (Constant Frequency) element in their calls. With horseshoe=

bats which have a mainly CF call, this gives a typical "warble tone" which=

you can also use for estimating flight speeds. I have IR cameras and a Ciel=

Heterodyne detector in a horseshoe bat roost and get more movement data fro=
m
the sound than the vision.

My recordings are on another system, but I'll try to send an example.

David Brinicombe