Redirecting sound to a file

Hi Alsa Experts!

I use a software package called Kaleidoscope Lite to analyse bat
calls. Part of the fun is using their audio playback feature to replay
sounds from a .WAV file at frequencies humans can hear. This typically
involves division of (say) a factor of 10 as the bat call is in the
range 20kHz up to 100kHz (very roughly).

I would like to save these snippets of sound [as they are played after
frequency reduction] to separate files for audio playback and have
submitted a feature request.

But it struck me that it might be possible to capture the sound in
some other way. Hence this post.

I am running Kaleidoscope Lite 5.6.3 (latest stable) on Linux (Ubuntu
22.04.3) using the aoss script to wrap the call to the product.

Regards,
Amit