Piston Collage (unofficial) specs:
----------------------------------

* Up to 36 simulataneous VOICES. Each voice can be either a 2 oscillator
  .ptvoice (created with PtVoice program), 4 oscillator .ptnoise (created
  with PtNoise program, generally used for non pitched sounds like drums
  or sound effects) and lastly .wav (up to 16bit, 44.1khz stereo).

  Each voice is permanantly attatched to it's own track. This includes
  .wav (i.e. if you want a 3 note .wav chord,you must load the same .wav
  into PxTone 3 times. NOTE: This limitation will be relinquished in an
  upcoming version).

* Each voice can have one of 2 simple delays, be panned, pitch bent,
  and also allows volume and velocity data.

* Other features include: comments and song title information stored
  inside the song and .wav rendering of songs for use in other
  applications (or for making into an mp3) and custom time signatures.