Les

FM-1 firmware · 2026.10.22

CS-1

An eight-voice synth in the spirit of the Yamaha CS-80, with dual channels, filters in series, ring modulation and touch response, played over MIDI.

Made by
twochannels
Released
October 22, 2026
Install
On the FM-1 Firmware Hub · source on GitHub
Scan
Scanned, nothing harmful found · Oct 31 What we checked
Last checked
October 31, 2026

What CS-1 does

  • CS-1 plays eight voices, each two CS-80 channels with sawtooth, pulse with PWM, noise, two filters and a sine after them.
  • It carries 52 factory sounds and the CS-80's 22 preset tones, paired as row I and row II.
  • An auto after touch curve makes every note swell by itself, waiting, rising, holding, then falling when the key goes.
  • The keys play polyphonically with velocity and pressure sensing, and SELECT acts as a ribbon that bends pitch and springs back.
  • SAVE puts the whole panel into one of 32 user slots, which keep their own flash sector.
  • Effects run from ring modulator and drive through chorus, tremolo, flanger and stereo delay with tape character to phaser and plate reverb.
  • MIDI arrives on USB and the TRS jack, with REC learning a controller's knobs and clock syncing the delay and sub oscillator.
  • A browser emulator runs the firmware itself, and Export presets writes your bank to a file.

Its modes

TONES
Pick each channel's tone from the two rows, see the sound's name, and set BRILL, RESO, MIX and VOLUME.
VCF
Set the high-pass and low-pass filters in series with their resonances.
VCF EG
Shape the filter envelope with IL, AL, attack and decay, drawn live as you turn.
TOUCH
Set how velocity and pressure push brilliance and level on that channel.
AUTO AT
Draw the pressure curve every note plays by itself, with DELAY, RISE, LEVEL and FALL.
RIBBON
Set how far and how fast the SELECT ribbon bends, or make it hold the bend.
REVERB
Set the plate's size, damping, shimmer and mix.
MIDI
Set the channel, the CC that acts as pressure, program change, and the learned bindings.

What Les checked

CS-1 2026.10.22Scanned October 31, 2026

What we checked for

  • The file matches the checksum the FM-1 Firmware Hub records for this version
  • It's the same file we saw when this release first came out
  • It opens cleanly as an FM-1 firmware, nothing damaged
  • It doesn't show up on your computer as a keyboard, mouse or other input device
  • It doesn't show up as a USB drive or network adapter
  • Its text mentions no computer command tools, like PowerShell, Terminal or a download command

What we found

  • MIDI and audio, as expected

StatusScanned, nothing harmful found

Les scans every firmware here whose file is public, and shows what it checked and what it found. A scan lowers the risk; it can't rule it out. This firmware is made by its author, not by Les or M-VAVE. Back up first, and install at your own risk. How Les scans firmware

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