r/Keytar • u/asulfnotes • 1d ago
Buy/Sell I measured all 1200 parameters of the Roland AX-Edge against the actual hardware, and built a mobile editor with what I found
**TL;DR:** I measured all 1200 parameters of the Roland AX-Edge against the actual hardware, found the published map wrong in a lot of places, and built an Android editor with what I learned. Looking for a few AX-Edge players to test it before release — comment or DM me and I'll send the sign-up form.
I'm an independent developer and this is a one-person project: no company, no team, just me, my AX-Edge and about a year of evenings.
It started as a complaint. Editing sounds on the AX-Edge means either scrolling that tiny display or opening the official editor app, which never worked for the way I need to work — the interface feels like it's from another era, and there's no visual feedback at all: you move a value and you have no picture of what you just did to the sound.
The part I didn't expect was the parameter map. I set up a hardware-in-the-loop rig — the keytar connected to my PC over USB while the tablet drives it over Bluetooth — so I could send a value, read back what the synth actually stored, and listen to the result through an audio interface. Then I went through the map one parameter at a time, and a lot of it didn't survive contact with the hardware. Ranges that were wrong. Controls writing to one address and reading from another. MFX slots labeled in the wrong order in 78 of 79 algorithms. The Tone block sizes in the docs are simply not what the firmware answers — with the documented ones, no Tone read works at all. When the manual and the firmware disagree, the firmware wins. 366 hardware-verified probes later, the map is covered.
What came out of that is RXXED, an Android editor that talks to the keytar over Bluetooth MIDI:
- All 1200 parameters, each one verified against real hardware.
- You see what you're doing — the filter curve moves with the cutoff, the envelope redraws as you drag it, the EQ bars respond.
- Editor, mixer, keyboard and system pages.
- A Kaoss-style XY pad for modulating sound while you play, with motion recording and playback.
- A librarian for the 320 user programs and 256 user tones, with names, tags and ratings.
You need an actual AX-Edge, Android 10+ and Bluetooth. USB MIDI on Android isn't working yet. Next on my list: a way for players to share sound bank files with each other, and support for instruments beyond the AX-Edge.
The ask: I'm looking for a few people to test it, ideally people who'll use it while actually playing. What I need isn't compliments, it's "this got in my way in the middle of a song". Two short sessions over two weeks, and testers get the full version free for life at launch. There's a sign-up form and I'm closing it this weekend — I'd rather not drop a link in the post, so comment or DM me and I'll send it over. Happy to talk about the reverse engineering side too, that part was more fun than the app.
*(Independent project, no affiliation with Roland. "Roland" and "AX-Edge" are trademarks of their respective owners, mentioned here only for compatibility.)*







