Everybody's favourite audio hacker Alexandre Ratchov (ratchov@) is inviting you to a concert in Grenoble (France). Read on to find out how this relates to OpenBSD:

Announcing a jazz concert here might sound off-topic, but for this one all synthesizers will run on a OpenBSD box. Unfortunately there are no sample recordings available on the web, only this site (in French).

For non-French speakers, the concert takes place at "the Hexagone" in the Grenoble area, Feb 27, 2015. You're welcome.

The music is experimental jazz using micro-tonal instruments, played by great jazz musicians: virtuoso flutist Magic Malik, Maxime Zampieri on the drums and Jean-Luc Lehr on the bass. We use acoustic instruments (fretless bass, drums) and synthesizers (flute-like synths, pads, and percussions). All synths and corresponding effect processors run on a OpenBSD/amd64 box.

There're few input midi(4) devices: a keyboard, a flute-like wind controller, a kit of drum pads, and control surface (bunch of knobs). They send short messages (aka midi events) whenever a key is pressed on the keyboard, the breath pressure changes on the wind controller, or a pad is hit with the stick. The synthesizer is a program (not published yet) that listens on a sndio(7) midithru port, calculates the wave corresponding to input midi events in real-time then sends the result for audio playback to a envy(4) based card. Then, the resulting analog signal is mixed with other analog sources (bass and microphones) and amplified. Everything is configured to have few milliseconds of latency between the moment a midi message arrives and the corresponding signal hits the amplifier.

The music is based on a theory developed by Frederic Faure which is too long to explain here, but it brings a unique sound by carefully choosing note pitches. So we use an additional program to calculate the pitch of each note submitted to the synth and to visualize various aspects of the theory to assist musicians, it also runs on the same box.

There will be a masterclass on this music presented by Malik, Frederic and me on Feb. 25, 2015. We'll discuss practical and theoretical aspects of this music, and if there's interest internals of the synths and the setup.

Maybe see you at the masterclass and/or for a beer after the concert.