Usefull web app
Load two audio files from your device and switch between them instantly, at the same point in the track.
Load a song whose exact BPM you already know and isolate any section in a easy loop, to write or evaluate an idea.
Set an audio's duration, in seconds or minutes, and instantly find the BPMs that land on an exact bar.
A metronome and on-screen chord chart in one: sync to incoming MIDI clock or set your own tempo.
A great 4 track tape recorder with MIDI clock plus an old school drum machine and a chromatic sampler.