MIDI Clock
MIDI Clock
MIDI Clock is a MIDI protocol that allows to sync the playback (transport and tempo) of multiple running sequencers, synthesizers or drum machines. This can be other software that is running on your computer, but also external MIDI hardware like a synthesizer or a drum machine. This can also be software running on other computers, connected to Renoise via MIDI cables.
There are two MIDI clock modes: MIDI clock master and slave. Renoise fully supports both modes.
The MIDI clock master sends series of 24 ppqn (pulses per quarter note) beat clock messages to all slaves. The interval of such messages allows the connected slaves to determine the masters tempo and beat position. Along with the 'beat clock' messages, 'Start', 'Stop', 'Continue' and 'Relocation' (Song Position Pointer) messages are sent to sync the timelines of the master and slaves.
Only the MIDI clock master can start or stop the playback or change the tempo. Slaves are forced to follow the master, thus the terms "master" and "slave".
Running Renoise as MIDI Clock Master
Setup Devices
To use Renoise as master, simply setup a MIDI clock master MIDI device in Renoises MIDI Preferences.
There you can also specify which message types you want to send from Renoise. Send only "MIDI Clock" messages if you only want to transfer tempo only to other slaves. Please note that Renoise only sends out MIDI clock messages while playback.
Adjust Offsets
You can use the 'offset' slider in the MIDI Clock master preferences to shift clock messages back and forth in time. This sometimes is needed to compensate delays, phase offsets, that are introduced by MIDI hardware. Audio latency is always automatically compensated by Renoise.
The easiest way to test and adjust this, is by using a steady metronome alike sound on the master and slave. If the sounds do not play back on exactly the same beat, try adjusting the offset slider in Renoise until they match.
Running Renoise as MIDI Clock Slave
Setup Devices
To connect Renoise to a MIDI clock master, again setup the a device in Renoises MIDI Preferences, but this time in the MIDI Clock Slave section.
To quickly enable and disable the connection to the master clock, use the small "clock" button in Renoises Transport Panel next to the BPM. This icon will only show up when a MIDI clock slave device is set up.
Important: Both, a MIDI device 'and' the sync clock mode icon must be enabled to sync Renoise to other devices.
After you have set up a MIDI clock device in the preferences, and the MIDI master is properly connected and sending messages, you should notice a small green blinking LED on top of Renoises screen:
The LEDs next to the small icon show the MIDI clock input in green and output in red.
Adjust Offsets
Just like in the MIDI clock master mode, you can correct small offsets between Renoise and the master with the Offset slider in the preferences.
Again, the easiest way to test and adjust the offset, is by using a steady metronome alike sound on both the master and slave. If the sounds are not in sync, try adjusting the offset slider in Renoise until they match.
Adjust Smoothing
MIDI messages often have only a very rough timing, thus the beat clock messages transferd from MIDI clock masters to Renoise, may result into an unsteady playback and tempo. Depending on how precise the incoming MIDI clock stream is, you can use the smoothing option to setup how fast Renoise should react on changes from the MIDI clock master: The higher the smoothing value, the more stable the sync and tempo will be, but the slower will Renoise react on 'real' BPM changes from the master. Try playing around with the smoothing to find a good value for your setup and needs.
Loading New Songs Without loosing Sync
You can detach and reattach Renoise to a running master at any time without loosing sync. To do so, simply stop the song in Renoise when running as MIDI clock slave instead of stopping the master. You can now even load a new song, then hit start again, and Renoise will resync itself as smooth as possible to the still playing master. This is extremely useful when playing live, because you then can continuously run a master, but can also switch songs in Renoise.
When "reattaching" Renoise to the still playing MIDI clock master, Renoise will shift its playback position as smoothly as possible to the master. This means, the closer you start playing at an on-beat, the less correction will be needed and the smoother the adjustment will be.