How to Create and Export a Sound Effect in Bfxr

Bfxr is a browser-based, open-source sound effect generator for games, based on drpetter's sfxr and written by increpare. You can create a sound by randomizing or mutating a preset, preview it with SPACE or ENTER, then export it as a WAV file with CTRL+E or save it as a .bfxr file with CTRL+S so you can keep editing later. This works for anyone who needs quick retro-style game audio and doesn't want to install a full DAW.

The basic workflow

1. Open bfxr.net in your browser. The tool loads with a sound already selected.
2. Press SPACE or ENTER to play the currently selected sound.
3. Adjust the sound using the on-screen parameters, or use the keyboard shortcuts below to randomize and mutate.
4. Preview again until you're happy with the result.
5. Export or save using CTRL+E (WAV) or CTRL+S (.bfxr).

Keyboard shortcuts

Using randomize, mutate, and lock

These three controls are what make Bfxr fast to work with:

• R (Randomize all parameters) — throws every parameter to a new random value. Use this to explore a completely different sound when you don't have a direction yet.
• M (Mutate current sound) — makes a smaller change to the current sound. Use this repeatedly to nudge a sound toward something you like without losing its character.
• L (Lock / unlock all parameters) — locks the current parameter values so that randomize and mutate don't change them. Lock a parameter once it sounds right, then keep randomizing the rest.

A practical loop: press M a few times, press SPACE to listen, lock the parts you like with L, then press R to vary only what's left.

Exporting vs. saving

• CTRL+E — Export as WAV. Produces a finished audio file you can drop into a game engine or editor. This is the file you ship.
• CTRL+S — Save as .bfxr. Produces a project file that keeps your parameter settings so you can reopen and keep editing. Use this for sounds you may want to tweak later.

Saving as .bfxr does not give you an audio file, and exporting a WAV does not preserve your editable parameters — so for any sound you might revisit, do both.

Common snags

• Nothing plays. Click on the page first so the browser gives the tool keyboard focus, then try SPACE again.
• You can't reopen a sound for editing. You exported a WAV instead of saving a .bfxr. Export is one-way; save the .bfxr if you want to come back to it.
• Randomize wiped out a good sound. Lock the parameters you liked with L before randomizing, or use M to mutate instead of R.
• You want to reuse a sound in another project. Use CTRL+C to copy and CTRL+V to paste it, or open a saved .bfxr with CTRL+O.

Bfxr also includes Footsteppr, a port of obiwannabe's footstep generator originally written in Pure Data, if you need footstep sounds specifically.