Incredibox

For arranging by ear, assign vocal loops to the beatboxers, then mute, solo and replace parts to change the groove. Recording captures the performance of those decisions, rather than just the final combination. The paid app adds a Mixlist and MP3 export, while the browser demo is a smaller taste. It is quicker to reach a convincing arrangement than in a synth sequencer, but the supplied loops limit the vocabulary, and the developer restricts commercial reuse of the music.