Hi Carl,
I use Spectroid intensively. My favourite is measuring the speed of a motor: I make the turning Motor generate some sound and I have directly the rounds per second.
I'd like to have a broader frequency range. The scale is limited to 6kHz. Sampling freq. is 96kHz, so a broader band should be possible. We have some bats in the garden and you could thus listen to them as well.
Good work
THX
Cheers
Detlef