Music & Audio · Open source

GrooveForge

Yann Poirier

MIDI synth with soundfonts, 92 microtonal scales, and offline band rehearsals

Download

Opens the official F-Droid page

GrooveForge screenshot 1GrooveForge screenshot 2GrooveForge screenshot 3GrooveForge screenshot 4GrooveForge screenshot 5GrooveForge screenshot 6

About GrooveForge

GrooveForge is a portable MIDI keyboard studio for Android. Plug in a MIDI controller, pick a soundfont, and play.

It began as a practice companion, light enough to carry on a phone or tablet, for rebuilding scales and muscle memory at a keyboard. It grew well beyond that, but it remains a tool for practising and playing, not a DAW.

Rehearsals

A band learning a tune together, without a studio. Everyone records their own part over a shared click, on their own phone, and the parts collect into one arrangement that every device holds a full copy of.

Import a recording to play along to — MP3, FLAC and WAV everywhere, plus M4A, AAC and the sound of a video on Android. Tap the tempo, then drag a marker to the first downbeat so the grid lines up with the music.

Every device delays sound on the way out and on the way in, which would push each take late. GrooveForge measures that delay on your device and shifts your take back by it, so what you played on the beat lands on the beat.

Nothing is uploaded anywhere and no account is needed. Devices sync directly over the local network: scan a code once, then opening the same tune is enough. No internet needed, and without Wi-Fi one phone's hotspot is the whole network.

Instruments

GrooveForge Keyboard — soundfont synth (.sf2) with bank and patch selection and MIDI channel routing. Every slot is independent.

Vocoder — mic-driven voice synthesis.

Stylophone — monophonic metal-strip instrument.

Theremin — touch pad with vertical pitch and horizontal volume.

Drum Generator — beat patterns from bossa nova to metal, with human feel.

Xen: microtonal scales

Hold a note, tap a scale. The note you are holding becomes the tonic, the keyboard locks to the scale built on it, and — for scales that are not equal-tempered — the keys it uses are retuned to sound as the tradition intends. One keyboard, one gesture.

92 scales across eleven families: Western modes; Arabic and Turkish maqamat; Persian dastgah; Indian ragas in just intonation; Chinese, Japanese and Korean modes; Thai seven-equal; Javanese and Balinese gamelan; Ethiopian qenet and Ugandan amadinda; Highland pipe, hardanger fiddle and Byzantine chant; historical temperaments; and equal divisions from 13 to 31 tones, Bohlen-Pierce, and Wendy Carlos's non-octave alpha, beta and gamma.

Retuning uses a full MIDI tuning table rather than pitch bend, so every note of a chord sounds at its own correct pitch. Out-of-scale keys grey out and retuned ones show their offset in cents.

Each scale says where its numbers come from: a temperament is exact, a maqam follows the convention that notates it, a gamelan is tuned by ear and varies between instruments.

Build your own scales too — any number of degrees, an offset per key, and a mute that keeps a degree playable while the scale lock ignores it. Import and export Scala (.scl) files.

Loopers

MIDI Looper — record and loop MIDI patterns with bar sync.

Audio Looper — record and loop live audio with bar sync, overdub and reverse.

Effects

Plate reverb, ping-pong delay, wah (auto or pedal-controlled), 4-band EQ, compressor and chorus/flanger, with BPM sync where it makes sense. Live Input routes a microphone or line-in through any of them.

And the rest

What's new in 3.3.0

Added - Wah: a Manual mode, where a new Pedal control sweeps the filter instead of the LFO. Assign it to an expression pedal or a CC knob. - Rehearsals: remove the phone speaker's bleed from a take recorded with the click on the loudspeaker, from the lane's menu. The original is kept. Changed - Auto-Wah is now Wah. Existing projects load unchanged. Fixed - Rehearsals: a track could briefly fall silent when playback started or the playhead moved.

How to install GrooveForge

  1. Tap Download — the app's official page on F-Droid opens.
  2. Install it with the F-Droid app (recommended, for automatic updates), or use the download button on that page.
  3. If Android asks, allow the F-Droid app or your browser to install apps, then tap Install.
  4. Open GrooveForge from your app drawer.

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