Is there any way to make Android emit a sound of arbitrary frequency (meaning, I don\'t want to have pre-recorded sound files)?
I\'ve looked around and ToneGenerator
Here's another blog demoing a simple synth plus some UI
http://audioprograming.wordpress.com/2012/10/18/a-simple-synth-in-android-step-by-step-guide-using-the-java-sdk/
You might also be interested in csound or pdlib (pure data lib) for android.