MIDI Clock
MIDI Clock
MIDI Clock is a MIDI protocol that allows you to sync playback (transport and tempo) of sequencers, synthesizers or drum machines. Such sequencers can be software that is running on your computer or running on other computers, but also external MIDI hardware like synthesizers or drum machines, connected to Renoise via a MIDI device and MIDI cables.
There are two MIDI clock modes: MIDI clock master and slave. Renoise supports both modes.
The MIDI clock master send series of 24 ppqn (pulses per quarter note) beat clock messages. The interval of such messages allows connected MIDI clock slaves to determine the masters tempo and beat position. Along with the beat clock messages, start/stop/continue and relocation messages are sent to sync the transport of the master and slaves.
Only the MIDI clock master can start or stop the playback or change the tempo. Slaves are always simply following the master.
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 to other slaves. Please note that Renoise only sends out MIDI clock messages when the song is running.
Adjust Offsets
Use the offset slider in the 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 both the master and slave. If the sounds are not applied with a small delay, 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 MIDI clock device in Renoises MIDI Preferences, but this time in the MIDI Clock Slave section. To quickly enable and disable the connection to external devices, use the small "clock" icon in Renoises Transport Panel next to the BPM. Both, a device and the sync clock mode 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 connected, you should notice a 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 applied with a small delay, 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. 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 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.
Please note that
Loading New Songs Without loosing Sync
You can detach and reattach Renoise to a running master at any time. To do so simply stop the song in Renoise as MIDI clock slave and not on the master. You can even load a new song, then hit start with the new song again and Renoise will sync itself again as smooth as possible to the master. This is extremely useful when playing live, because you then don't have to stop the master at all, but can also switch songs in Renoise.
When "reattaching" Renoise to the 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.