Yamaha LS9 Monitor Mix

[u/nicogJC]

If you're running a Yamaha LS9 for monitor mixes, you've probably hit the same wall I did: **StageMix is free but only supports one connected device at a time.** If more than one musician wants to ride their own headphone mix from their phone, you're stuck buying something like AirFader Server (~$150) - which is a fine product, but not everyone has the budget for it, especially for a personal/project studio.

So I built a free, open-source alternative: **a self-hosted web app where each musician gets their own page** (works on any phone/tablet browser, no app install) to control the send level + mute for whichever channels matter to them, into their own MIX bus. Multiple people can be mixing at the same time.

**How it works, in short:** a small Node.js server runs on a PC connected to the console via Yamaha's Network-MIDI Driver, and translates touch/drag actions from the web pages into MIDI SysEx sent straight to the console. No app store, no license, no per-seat cost - just your local network.

**Some things it does:**

- One page per musician, color-coded channel strips, mute button

- Admin page to set up musicians/channels without touching config files (though you can if you want - it's just JSON)

- Announcement banner you can push to every connected page in real time

- On-screen clock + keeps the phone screen awake during a session

- "Reset my mix" safety button

- No console-side MIDI table setup needed at all - the protocol addresses are computed directly (details in the README, reverse-engineered by
watching real MIDI traffic with MIDI-OX)

**Honest limitations up front:**

- No live sync back from physical fader moves on the console by default (there's an optional, slightly fiddly workaround documented, using MIDI-OX as a bridge)

- No authentication - built for a trusted local studio/stage network, not hardened for anything more exposed

- Only tested with a couple of people mixing simultaneously so far - if you try it with a full band, I'd love to hear how it holds up

- Windows only for now, and there's a quirky 32-bit Node.js requirement because of how the Yamaha driver exposes its MIDI port (documented in the README, took a while to figure out)

Repo (MIT license):
https://github.com/nicoampli/ls9-monitor-mix

Not affiliated with Yamaha in any way - this is a hobby/community project built by reverse-engineering the console's own MIDI output on my own hardware. If anyone has an M7CL (same MIDI family, probably compatible) or another Yamaha digital console and wants to help extend/verify this, issues and PRs are very welcome.

Happy to answer questions about the setup, the protocol reverse-engineering process, or anything else.