Connecting LPX to other devices (Yamaha SEQTRAK)

[leonidaslundell]

Hi, thanks for the amazing tool!

I realize this is a big question, but I am not familiar with editing HEX code so I would appreciate any direction!

I recently bought a Yamaha SEQTRAK and was disappointed to realize that the devices do not talk to each directly. I used the midimonitor.com and read the programmer documentation, and it seems that the main difference is that the LPX sends communicates through Note On velocity 127, and Note On velocity 0, while the SEQTRAK seems to communicate with Note On velocity 100, and Note Off velocity 0.

This is of course not confirmed, as I am unable to edit the .syx file, or find an easy way to send signals over USB.

To summarize, is it possible to change the note on/note off behaviour, and if yes, can you point me to workflow?

Thanks!

[mat1jaczyyy]

Hey,

how are you attempting to interface with the Yamaha SEQTRAK currently? I'm not familiar with it, but it looks to be a standalone device of some sort. The Launchpad X only offers a USB port and no direct MIDI ports. Is your LP X talking to the computer first, and then the computer talks to the SEQTRAK?

[leonidaslundell]

Appreciate the quick reply!

It's a usb C to usb C connection. There are YT videos of people connecting other novation products to the seqtrak, i think the issue is specific to the communication of the LPX.

[mat1jaczyyy]

Ah, so the SEQTRAK is acting as a USB host in this exchange?

Yeah, you'd need to hack on the firmware to change these send values. I don't know the exact points in the firmware, you'll need to do the reverse engineering yourself, you can use our ghidra stuff as a starting point I guess...

The firmware binary to edit is here and you can use bintosyx (build with make tools) to convert it into an acceptable firmware update.

@gabonator has done significantly more sophisticated hacks on the Mini MK3's firmware (very similar to X firmware), so you might have some luck reading through the source code here.

[leonidaslundell]

Super, thanks for pointing me in the right direction!

What do you think @gabonator? Is this doable or a nightmare fools errand?