software · Live
OWL: Operator Waveform Lab
Describe a sound in plain language, shape it with sliders, and export it as a Yamaha DX7 or SpaceAge 80s FM patch.
OWL is a browser-based patch designer for the Yamaha DX7 and the SpaceAge 80s FM synthesizer. Describe a sound in ordinary language, audition it on the built-in keyboard, refine it, and export it. You can also open an existing cartridge and edit any voice in it.
From description to patch
OWL reads your description for the kind of instrument (a Wurlitzer, a flute, tubular bells) and for adjustments such as brightness, attack, release, grit, vibrato, and velocity response. It understands phrases like “not bright,” “very dark,” and “slightly metallic.” It then chooses a starting voice from a library of 42 original voices written for the project and 28 voices from the Electronic & Music Maker / Music Technology type-in series, credited to their original programmers.
Instead of randomly rebuilding the six-operator structure, OWL makes FM-aware edits to that voice, such as changing modulation depth, envelope contour, and off-series ratios for metallic tones. It renders test notes, measures the result (brightness, attack, decay, release, and inharmonicity), and keeps adjusting until the measurements match your description. The page then explains which voice it started from, what it changed, and how close it got.
Keep shaping the sound
Sliders in seven groups (Tone, Layers, Shape, Movement, Pitch, Playing, and Output) let you keep working in sound terms instead of DX7 parameters: brightness, attack, sustain, vibrato, pitch scoops, velocity response, and more. Your description sets their starting positions, and every change rebuilds the voice from that starting point, so moving a slider back really does undo it.
Layers and algorithms
OWL finds a voice’s layers and their roles (tine, sustain, and hammer) and edits them individually. You can adjust the tine’s level, pitch, and touch, change the sustain tone, balance attack against sustain, and add a hammer, which is a fixed-pitch, fast-decay strike. When no operator is spare for the hammer, OWL switches to an interchangeable algorithm that keeps the other layers’ routing, then rebalances by measurement. These techniques follow the electric piano and Tubular Bells tutorials from Power DX7, checked against Chowning, Martin Russ, and Bo Tomlyn. Controls that a voice can’t support are greyed out, with the reason.
The algorithm card opens the full chart of all 32 DX7 algorithms, drawn the way the DX7’s front panel prints them. Interchangeable algorithms are marked, and picking one remaps the voice onto it, keeping as much of the routing as possible and reporting how many connections survived.
Open, edit, and collect
Open a DX7 .syx file (a 32-voice cartridge, a raw bank, or single voices) or a SpaceAge .ssynth patch, pick any voice, and edit it with the sliders, starting exactly as loaded. Edited voices go into a separate 32-slot “My cartridge,” which is kept in your browser and downloaded as its own .syx. The file you opened is never modified.
Leveled so it doesn’t clip
SpaceAge and Dexed hard-clip a voice at full scale, which distorts patches with several loud carriers or strong feedback. OWL levels every voice automatically so that its loudest note peaks 1 dB under the clip point, and the preview reproduces that clipping, so you can hear a problem before you export.
Export or send
- a native single-patch
.ssynthfile for SpaceAge 80s FM, - a single-voice Yamaha DX7
.syx, or - a 32-voice DX7 cartridge
.syxholding the chosen voice plus 31 related candidates and variations.
In Chrome or Edge, Send to synth also sends the current voice over Web MIDI to a DX7, TX802, Dexed, or any compatible synth. It writes only to the synth’s edit buffer, so nothing stored on the synth is overwritten.
Good to know
The in-browser preview follows the DX7’s envelope, output-level, velocity, and keyboard-scaling math closely, but it is an approximation of the hardware. Everything happens locally in the browser, so no audio or prompt data is uploaded.
#music #software #fm-synthesis #dx7 #spaceage
