Free Browser Instrument

Horn of Abraxas

An experimental drone synthesizer for dark, cinematic sound

A free instrument built for texture, tension, and tone. Play it in your browser — no download, no installation, no plugin required. Shape layered drones, corroded bells, and vast spectral spaces with a fully interactive synthesis engine.

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Drone FM Synthesis Additive Noise Experimental Cinematic Free No Download

About

A single note, held long enough, becomes a world

A drone is not a static thing. It is a note stretched until time loses its grip on it — and in that stretching, something strange happens. Simple elements begin to move against each other. Harmonics drift. Filters breathe. The ear, given nothing to chase, starts to listen differently, finding complexity inside what is essentially one sustained idea.

Horn of Abraxas is built around that principle. Its synthesis layers — additive harmonics, FM modulation, filtered noise — are each simple in isolation. Held together and set in motion, they create the illusion of something far more alive than the sum of their parts. Drawn from the cinematic sound worlds of composers like Jóhann Jóhannsson, where a single tone can carry the weight of an entire scene.

The instrument runs entirely in your browser. Everything you hear is generated in real time — no samples, no loops, no pre-recorded audio.

"A drone is the simplest possible musical act — one note, sustained. What makes it powerful is that simplicity creates the conditions for complexity to emerge on its own."

— Daniel Ruppar
Additive Drone Layer
Stack of pure sine partials with independent even, odd, and inharmonic harmonic control. Shape from a clean sine to a full organ to metallic bell clusters.
FM Engine
Two operator pairs with self-feedback. Ratio sweeps from warm sub-bass through brassy mid-range to harsh industrial clang. Index controls modulation depth.
Noise / Breath Layer
Colored noise through a resonant bandpass filter that tracks the note frequency — from airy breath to narrow screaming formants. Adds the corroded-string quality.
Sub Oscillator
A pure sine an octave below that fades naturally on high notes, adding weight and subsonic presence to lower register playing.
Filter Envelope
Per-voice resonant lowpass filter with a dedicated envelope amount — keeps the sound alive and moving even on long sustained notes.
Reverb, Delay & Distortion
Convolution reverb for vast spaces, tempo-free analog-style delay with feedback, and a waveshaper distortion for harmonic grit and tape saturation.

How to play

Start simple, go deep

Click any key on the on-screen keyboard to activate audio. Use your computer keyboard for hands-free playing, or combine mouse and keyboard for chords and layers.

White keys
A S D F G H J K
C D E F G A B C — one octave of the white keys mapped across the home row.
Black keys
W E T Y U
C# D# F# G# A# — the sharps and flats, mapped to the row above.
Octave shift
Z X
Z shifts down one octave, X shifts up. Range is ±2 octaves from C3. Also available as buttons on the keyboard panel.
Hold mode
Hold button
Toggle Hold to sustain notes after you release them. Click a held key again to release it. Layer up drones this way.
Presets
Preset row
Six starting points: Mandy Drone, Corroded Bell, Deep Void, Machinery, Ritual Pad, String Ghost. Each loads a complete parameter state.
Knob control
Drag or scroll
Drag any knob up or down to adjust, or use the scroll wheel over a knob for fine control. Changes take effect in real time on playing notes.

Play it here

Click any key to activate audio. Works in Chrome, Firefox, and Safari.

Layer Mix
FM Engine
Noise / Breath
Harmonics
Movement
Filter
Distortion
Reverb
Delay
Envelope
Your Saved Presets
Keyboard — [A–K] / [W E T Y U]  ·  [Z] octave down  ·  [X] octave up
click any key to begin
C3
Signal