Hi, so I had the same problem as everyone else here: I wanted to
record pads 1-6 of my Nord Drum 3P via MIDI channel 10-16 into 6 tracks of my sequencer (in my case a lovely Polyend Seq), but the Nord Drum 3P only sends MIDI Out Notes on a single channel, so I recorded all 6 pads into a single track which was quite a mess.
So what I wanted was
- change "MIDI channel 16, Note On, Note value #60" to "MIDI channel 10, Note On, Note value 60"
- change "MIDI channel 16, Note On, Note value #62" to "MIDI channel 11, Note On, Note value 62"
- change "MIDI channel 16, Note On, Note value #64" to "MIDI channel 12, Note On, Note value 64"
- change "MIDI channel 16, Note On, Note value #65" to "MIDI channel 13, Note On, Note value 65"
- change "MIDI channel 16, Note On, Note value #67" to "MIDI channel 14, Note On, Note value 66"
- change "MIDI channel 16, Note On, Note value #69" to "MIDI channel 15, Note On, Note value 67"
and then the same for Note Off, as this is what the Nord Drum 3P does - found that out with the Mac app "MIDI Monitor":
https://www.snoize.com/midimonitor/
[note that the PITCH of the note is transmitted in another MIDI value, so you can still change the pitch in the Nord Drum 3P and send it and play it back]
Here's how I achieved that:
1. bought an Event Processor Plus
http://www.midisolutions.com/prodepp.htm from MIDI Solutions and a $20 USB-to-MIDI cable from Amazon
(the Note On / Note off commands above are already 12 commands, the Event Processor non-plus can handle only 10 while the Plus handles up to 32)
2. connected my Macbook with the cable and plugged it into MIDI In of the Event Processor Plus … but the cable couldn't power the device, so I also
3. connected MIDI Out from the Nord Drum 3P to MIDI Out of the Event Processor Plus to power it
4. selected the above "Map a MIDI Event" settings in MIDI Solution's free app
http://www.midisolutions.com/progtool.htm and sent them to the device … remember to change the setting numbers, here's my code:
5. if you do everything right, the device will flicker for 1 second after EACH transmitted command. If you do it wrong, it will at the most go dark for a fraction of a second
6. I could then unplug the device and use it directly with the Nord Drum
So now I'm recording my 6 pads through 6 channels into 6 sequencer tracks, mission accomplished
Programming
Noteworthy is what didn´t work to do the programming - apparently some instruments / keyboards / sequencers change or withold bits of the transmitted MIDI programming:

Mac --- usb ---> Arturia Keystep 32 --- midi ---> Event Processor Plus

Mac --- usb ---> Polyend Seq --- midi ---> Kenton Thru 12 --- midi ---> Event Processor Plus

Mac --- usb ---> Argon8M --- midi ---> Event Processor Plus <--- midi power --- Nord Drum 3P

Mac --- usb midi cable ---> Event Processor Plus <--- midi power --- Nord Drum 3P
Everyday use

Nord Drum 3P --- midi ---> Event Processor Plus --- midi ---> sequencer

Nord Drum 3P --- midi ---> Event Processor Plus --- midi ---> Arturia Keystep 32 in Thru Mode --- midi ---> sequencer
Hope this helps

Still don't understand why I need to buy a 169 € MIDI translator while the myriads of MIDI Out problem posts in this forum could ALL be solved with a simple firmware update!
Note (edited): One bummer is though that the MIDI Solutions Software Tool is
only working up to Mac OS 10.14 Mojave, not Catalina or newer. It does work with even OS 10.6 that I have on a very old Mac mini that I use as a server and for network backups.