Quick update for anyone who is wondering about this:
MIDI over Din has a hardware limitation of 3125B/s (bytes per second), MIDI over USB doesn’t have a defined limitation, but is often limited to this rate for compatibility reasons. 14-bit midi messages contain 4 bytes of data. Using these figures + some pretty rough maths that doesn’t even account for note data, velocity data, etc:
200bpm (assuming that no one here is making music any quicker than that) = 300ms per quarter note.
Therefore 24ppqn data is sent every 12.5ms.
1s/12.5ms = 80 midi sending ‘events’ per second at 200bpm, 24ppqn.
4 bytes per ‘event’ = 320B/s (so 1 automation lane at 24ppqn, 200bpm would be sending a maximum of 320 bytes per second).
3125/320 = MIDI hardware limitation / maximum rate per lane = a cap of 9.77 lanes @ 24ppqn before you start to overload any MIDI Din device.
This explains why most people have struggled to get more than 10 lanes of interpolated 14-bit MIDI data to work at a rate of 24ppqn. The limitation isn’t created by Hapax or the FH-2, it’s created by the MIDI 1.0 specified hardware (as always).
The points to takeaway here:
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If you want to use Hapax to send 14-bit MIDI data at 24ppqn to any MIDI device, don’t use more than 9 lanes per MIDI Din output (or less if you’re programming a lot of note, velocity, other… data) and you’ll be fine. (In this case, probably don’t buy an FH-2 CV expander.)
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If you NEED to send more than 9 lanes per Din output; reduce the PPQN on Hapax, don’t use interpolation, or just use 7-bit MIDI (7-bit MIDI still uses 3 bytes per message though… For the FH-2 you could use it’s smoothing which smooths 7-bit messages to 14-bit anyway and it will probably allow about 25% more lanes…).
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If you need continuous control over 9+ parameters in the modular world then using some kind of cv recorder (Hermod+…) would be a good workaround.
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Or use the FH-2’s internal LFOs, envelopes, etc, etc, etc…
Hope this helps.