Bat Detector

Simply connect an inexpensive USB microphone to your iPhone or iPad to open up the amazing world of bat acoustics! 

All European bats and many of the world's "microbats" navigate, hunt and communicate using ultrasonic sounds, beyond human hearing. Bat Detector reveals those sounds to human ears, and has two different methods to make bat sounds audible. Firstly, it supports the "classic bat detector mode" of heterodyne bat detection. Heterodyning is a simple process that operates in true real-time, demodulating the bat sounds with a carrier signal just like an old transistor radio, but without any manual tuning. Bat Detector tunes into he strongest bat signal, and the heterodyne process turns any bats sounds in hears into percussive cracks, pops and slaps. The harmonic content of the sounds is distorted and mangled, rhythm is preserved. 

Time Expansion operates in quasi real-time, capturing small snippets of bat sound and playing them back at 1/16 speed. 16 is a good number - it brings the bat sounds down to a good range for human hearing (from between 1kHz to just under 7kHz), and it preserves the harmonic relationships between the bat sounds. And as a bonus it is a musical transformation. The bat sounds are not only slowed down but are transposed down by exactly 4 octaves, so if a bat calls a C#, you will hear a C#, but 4 octaves lower. You will be surprised how beautiful and musical the bat sounds are when time-expanded.

When "RECORD" is engaged Bat Detector will trigger a 5 second full-spectrum recording at 384kHz when it hears a bat, or something that it thinks sounds like a bat. These are not the recordings of the sounds you hear coming from the detector, but are the sounds going into the detector - the true sounds that the bats made, too high for humans to hear. You will need specialist software to examine these files after you export them from your device to a computer.

If you want to experience bat sounds during the daytime, in a classroom environment, or when there aren't any bats around, just turn on Demo Mode in the Bat Detector section of the settings App, and Bat Detector will loop through a collection of bat recordings from Wiltshire, England.