intelligent accompanist bleg

[gusl]

I'd like to get some intelligent accompaniment software, to help me practice my solos. As you probably know, the accompaniment in play-along CDs lead rather than follow. So I want a system that can detect my rhythm through a microphone, and accompanies me properly.

Any tips, anyone?

Comments

[peamasii.livejournal.com]

A lot of sound equipment will let you tap in the rhythm to modify the tempo of a playing CD, for example. The problem is that you want to do that hands-free, but beat detection only works on hard constant beats, not on violin sounds. I doubt there's any free software that will do playback time-stretching properly in real-time, leave alone the kind of beat detection that you're talking about.

I would invest in a hardware unit like a mini-jam unit made by Boss which allows tap rhythm adjustments and then look for a pedal controller which you can tap on with your foot, but obviously the input would have to be mapped in MIDI to allow you to interface the pedal. Alternately a software setup with Cakewalk Studio or something similar might also work, but the usability will get more little complex.

[gustavolacerda.livejournal.com]

Beat detection with violin can't be that hard. Not only is there normally an loud accent on the beat note, but there are also occasionally pauses, note changes and bow direction can be easily detected in the generated wave (in fact, I can only tell bow direction if I look at the wave: the sounds are indistinguishable to my ears).

[peamasii.livejournal.com]

OK, but beat-detection is normally implemented to match beats to beats, not beats to soloing violin :-)

Say you are playing quarter-notes for one measure at 92 bpm, next at 88 bpm, next at 95 bpm and next at 95 bmp. Then next four bars you're playing eight-notes in similar tempos. The machine would effectively alter its rhythm about 6 times in 8 bars, which is not what you want.

What you want is to make a few rhythm changes in one piece, and for the rest the beat to stay constant. Those changes are best determined either by a tapped rhythm or at set places in the composition.

[gustavolacerda.livejournal.com]

Say you are playing quarter-notes for one measure at 92 bpm, next at 88 bpm, next at 95 bpm and next at 95 bmp.

Ok, suppose you have bad rhythm. Most people can still detect what rhythm you are trying to keep. How do they do it? It's complex and requires intelligence. Rhythm induction is not a simple problem. That's why it falls under AI.

In any case, if the machine knows the tune that you're trying to play (e.g. has a representation of it in a MIDI file), it can do a much better job. Just like in a human accompanist. Even better would be it if it had a representation of expressive performance (i.e. intentional tempo changes).