I found a solution that works for me, I'll share it here briefly in case someone is having same issues.
It's not BSP specific, but should help anyone with similar MIDI hardware + MTR setup to
synchronize recordings.
The Zoom R24 allows for any compatible audio track to be played as metronome sound.
So I realized it is possible to use an LTC signal as a metronome track,
and route it via phones output to a device capable of LTC -> MTC/MMC conversion.
Hardware devices for this purpose exist, but they seemed a bit overkill and out of my price range.
There might also be software for Win or OSX platforms that can do this conversion,
but they too are unsuitable for me since I'm using Linux on my PC.
Gladly there were OSS packages for Linux that allow for routing, conversion and retransmit of
different time code protocols.
Namely, you need following software components: jackd2, qjackctl, a2jmidid and ardour DAW from
version 3.x onwards (technical explanation of ardour's ltc sync:
http://gareus.org/wiki/a3extsync).
I'm using ardour 3.5.403 from debian/ubuntu repos, that seems to work.
I wont go into specifics of the configuration since my head is still spinning from
examining this setup, but in short you need to do following steps:
- start ardour3 and configure it to use jack as audio driver and specify your capture device
that will input the LTC signal.
- export hardware midi devices (like the Beatstep Pro) to jackd with "a2j -e" command,
this can be made automatic from qjackctl setup window to run every time jackd has been launched,
then you will probably want to use a2jmidid daemon program running in background.
- configure ardour3 session properties and program preferences to support incoming LTC
signal of your choice.
- route your soundcard capture device to ardour's LTC-in, and also ardour's outward MMC/MTC/MIDI Clock
ports or whatever signals you want to the hardware midi device, in this case Beatstep Pro.
The routing can be done either from ardour (Window -> Audio/MIDI Connections),
or from qjackctl Connections window.
- use a software tool to generate LTC wav file, or check out page
http://elteesee.pehrhovey.net/ for generating such file online. For testing I used 30fps 44.1kHz 24bit wav file, with start
time 00:00:00:00 and duration longer than I expect my recordings to have like 30mins or so.
- from MTR set metronome to play the generated LTC wav via phones out to computer soundcard.
Remember to set playback and capture levels to something reasonable so ardour will recognize
the signal.
- in ardour press the clock sync source from main window to wait for external sync signal.
And the end result?
After pressing rec from the multitrack recorder, your Beatstep Pro should start playing
when it gets MMC/MTC commands from ardour, and your MIDI gear starts playing sounds.
It will take something like less than a second for ardour to recognize and catch up on the LTC signal,
depending on your audio setup latency, but it will soon lock sync, and short experiment
showed the tracks/loops will be in sync after you trim out the first bar or so.
Ardour's MIDI Tracer can become handy if you're having problems.
- Jah Has Soundwave -