Mixbus can synchronize to external hardware or software in three ways:
- LTC (Linear Time Code, sometimes called SMPTE) fed from an audio input.
- MTC (Midi Time Code) fed from a MIDI input
- Midi Clock (sometimes called Midi Beat Clock) fed from a MIDI input
In all 3 cases, Mixbus can be the Master ( it sends the timecode to the other devices or software) or a Slave (in which case Mixbus will “chase” the other source). In most cases, the digital workstation should be the Master device, so Mixbus will normally be the Master. But there are cases when you need to do it the other way, too.
Each method has different requirements and capabilities.
- LTC (sometimes called SMPTE) uses a channel of audio to encode a continuously-running timecode position. The master device generates this signal, and the slave devices use this stream to determine the master’s position and speed. LTC has the benefit of using everyday audio signals for sync, but the underlying software has to be pretty smart to decode the position. Implementations vary from very good to very bad.
- MTC is similar to LTC, but uses a MIDI channel to encode the position. It is much easier for developers to interpret, and it uses widely available MIDI cables and connections. However it is slightly less robust because of the decoupling between the MIDI and the audio clocks in most computers.
- JACK allows 2 or more software applications on your computer to share their timecode position and speed, without any audio or MID connections required by the user. JACK synchronization has several benefits over MTC & LTC, but it is not likely to be available on most commercial software, or external gear like a drum machine.
The “Internal/External Sync” button enables or disables external chase. If external sync is disabled, the button shows “Internal”, and Mixbus will use its own internal clock and transport controls.
You select the synchronization source from the Preferences. Sync source is globally selected, it doesn’t change with each session you have open. This matches most people’s needs, since most people have a studio setup that doesn’t change depending on the session they are using.
When syncing to external timecode, you will see a display showing the current external timecode value, and a “Delta” value indicating Mixbus’s offset from the master device:
Mixbus’s timecode sync functions are largely developed by the Ardour open-source community. For more details, see the applicable chapters in the Ardour manual: http://manual.ardour.org/synchronization/timecode-generators-and-slaves/