I want to create synchronized clicks to control my SQ-1 sequencer and Korg Volcas. Can anyone recommend a plugin for this or something that just plays a click (or a sample) on an incoming MIDI note ? Ideally something simple and with low latency and low CPU load.
There is a MIDI clock generator LV2 plugin. Is that what you need?
I need something that creates actual clicks, a bit like a metronome but no fancy sounds, just single pulses.
What rate so you want the audio pulses? One per beat synchronised to sequencer clock?
Ideally highest speed = 1 Pulse per Clock message and a selectable divider to slow down. I wrote something like this in python with mididings. It works well with a modded USB/serial cable as pulse output but I would prefer to create the clicks directly in Zynthian. Another option might be to use Zynseq to sequence clicks.
Both of those devices support MIDI clock for sync. Why make it hard?
The problem with MIDI clock is that the speed is fixed and cannot be changed easily on the fly. With the SQ-1 for example you have to restart into config mode, change the divider and restart again just to make the sequencer clock run on 1/16 instead of 1/8 notes for example. As I like live jamming I want to do these things with a simple controller change.
I am not familiar with the interface on these devices. MIDI clock is continually variable and will clock at 24 pulses per quarter note so the rate of clock changes with tempo set in Zynthian. If there is some other workflow step within these devices that is easier with its click detection than its MIDI clock slave then I feel they have missed a trick and you will have to create a click track, e.g. by adding an layer with a simple synth and creating a pattern in zynseq.
I did some benchmarking which showed Calf monosynth to have quite low resource use so that could be a candidate but… what audio output do you plan to use? Surely you want to use the Zynthian audio outputs for Zynthian synthesis / audio processing?
Clicktrack is exactly what I was thinking about. Thanks for the mentioning Calf monosynth. I will give that a try. As for the audio output there is plenty of choice as I have four outputs plus the headphone jack. Ideally I would like to use the “lower fi” headphone jack for the clicks, but wonder if it might have more latency due to kernel overhead from the PWM DAC system.
The other option I am considering is to port my python program to PD and let it run as a PureData patch. Never used PD, but this might be an interesting little project. I can see that PD has a realtime MIDI interface that can handle clock.
Anyway, i think it’s a good idea to implemet a simple jack client that generates a square wave synced with the internal clock. This could be connected directly to the RBPi output, without jackd. In such a case, RBPi output couldn’t be used for headphones. This was my original idea before implementing the headphones output.
Regards,
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Could we swap between the two modes, like we do with Multi-timbral/Stage mode?
I had the idea of implementing SMPTE on the RBPi output bu then thought it might be as easy to add a simple filter / attenuator to a GPI output and use that. Both SMPTE and click could be provided this way. It feels like overkill to add a synth layer and generate complex audio waveform then push that into jackd to synchronise and render on the audio outputs when all you want is a click which a GPI would create. (Need a simple RC filter to avoid horrible high frequency artifacts.)
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Korg Volcas etc. require a 15ms positive pulse. The RC filter is essential when using a digital output. Otherwise the devices started skipping steps. In my experiments 10 KOhm in series and a 100nF cap to ground at the output did a good job.