What do you want out of your transport control?

Do you just want a row of buttons that kick off the run/reset of your clock module? Do you use time codes? External master clocks?


Start/stop/continue are easy to interface; just have a reset, start and stop pulse with an extra rolling gate. Then just slap it in to Impromptu CLK or your other favorite clock. Also easy as far as doing Rack->MIDI back.

Ticking is supported but its in 1/24ths of a quarter note. Would have to convert it to whatever the Rack standard is for clock pulses (and probably some knobs.) Not sure how many Rack users are using hardware/external master clocks (I mean, a couple of DAWs like Ardour will do this too.)

Absolute time seems dubiously useful. There’s MIDI for it, external standards, and JACK supports it, but I don’t get the impression that modular really complies with that kind of exactness of timing. Would probably have this as a 0-10 CV that increases by some small value per second and rely on scaling knobs or other modules to convert the absolute time in to whatever else was needed.


a clock like the (Impromptu clocked) with the play , stop, pause, and jump to the start

but to me, the most important feature could be the ability to be master or/and slave of the jack transport.


This functionality shouldn’t be built directly into Rack. It should be supported by Rack via support of underlying protocols (ie. MIDI), but that’s it.

You want it, you get someone to code a Plugin>Module that will do it.


Those would be easy to add actually, but it would likely have to be a new module. Since release 0.6.13 of Clocked, the run button now serves as a play/pause control, and with reset being equal to “jump to start”, there would just be the stop to figure out. I would think that stop is like pause except instead of holding the clock outputs at their levels, it would bring them down to 0V, but that is not ideal since when starting the clock again, some shift registers, sequential switches and sequencers would see the restarting clock pulses as new clock edges when they in fact aren’t, which would desynchronize the track. I have noted your comments David, and if in fact people want separate CV inputs for restart, play, pause, stop, it could potentially be done in a new clock module.


As far as MIDI and JACK transport specs, no. The semantics for MIDI’s stop and continue is pause and resume, and the start message is “reset, then resume.” Current behavior is correct in that regard.

We do however get restart+resume, pause, and play as separate messages while most Rack clocks want edge toggles. Can probably pave over that with a simple S/R latch and then clocked doesn’t have to change at all (so long as the user doesn’t manually desync it.) Although how do we intentionally trigger a reset+resume now that we’re intended to ignore start triggers within ~44 samples of a reset?

The standard is actually to ignore clocks within 44 samples of a reset, not the run, if this is what you’re referring to as a start trigger. Also, when Clocked is in sync mode, the first clock edge after a reset is not subject to this constraint since the context is different and we actually want to handle that clock edge so that the clock can start up quickly. My comment may not be fully relevant, as I may be a bit off regarding what you are discussing, so apologies if this is the case. I’m now just getting a good feel for clocks, resets and runs just in the area of pure Rack, not yet ready to tackle MIDI issues quite yet! :slight_smile: