I can confirm there is a BUG with AMP : NRPN allocations
I am not going to comment on OT control of the Syntakt - I am using Max (like a monitor) to sniff/send/debug the midi i/o
There is a problem with the NRPN allocation on the AMP Parameters
It’s also confirmed borked in the Documented allocation numbers for the LSB parameters
What is now obvious was only evident to me after i sniffed the NRPN strings from the ST
The table demonstrates the control issues
The three X in the table show the parameters which do not take control over NRPN, the 1,24 pair for Attack are indeed working as an NRPN control of ADSR Release, however, this Pair is assigned and is sending as the same pair from four Controls ADSR-Attack, ADSR-Sustain, ADSR-Release and AHD-Attack
Only ADSR-Release responds to the NRPN string, so there are 3 non working control assignments on that table, everything else works fine
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The ST will understand CC and NRPN when set to NRPN output
The Octatrack will see a string of four CC messages for every NRPN string you send on the ST outwards
CC99 CC98 CC6 CC38
The values of these CC control messages are respectively
NRPN MSB num / NRPN LSB num / MSB val / LSB val
The CC number for Volume is 7, the CC val is identical to sending only the MSB val (or with LSB val 0)
So the OT will not meaningfully process the NRPN string as there is no correlation with the relevant CC numbers
If the OT listens(learns) from an NRPN string it will be meaningless as it will think you are using one of the CCs from the four above, likely CC99, or CC38 depending on its learning algorithm
Everything else you discuss is just a consequence of using a coarse controller to talk to a device capable of finer resolution
When using Max, it’s an easy process to send NRPN and everything works fine - although ironically there’s no LSB resolution on any AMP Envelope parameters to access - so CC is much better for AHDSR as it does not needlessly HOG the serial comms with excess data (that also isn’t working properly)
So rather than awaiting a Bug Fix - just use CCs 79 through 83