I've done some research on audio and found a very good summary here Wiseandroid.com | Intro to the three Android Audio APIs
The API that does all the raw audio is "audiotrack". The description of the API is here AudioTrack | Android Developers
and it looks perfect for things like games where you want to play short audio files with the minimum latency, and also build up an audio file in an array using math to create sine/square/triangle/sawtooth and even fancy things like additive synthesis using sine waves.
Is this API something that would be hard to port to Basic4Android?
And just a general question - that Java code looks almost identical to the code you would use in Basic. Rather than wait until you port an API into Basic, is it possible to talk to the Java code directly using this method Basic4android - Reflection