This app is my fav, no doubt. One thing though, the Xperia has a strange flaw while connected to the car stereo with charger and jack. Some 15 seconds after playing the last sound, whatever the kind, it releases the signal termination on the audio output, resulting in quite annoying noise (generator/car electronic).
I'd like to see an option to play zeroes while the app is running, to keep the audio output terminated.