Free is enough for most one-off jobs. Pro raises the file and batch caps; Pro + Media unlocks GB-scale streaming and unlimited duration.
Larger files supported on Developer (5 GB CSV) and Enterprise (unlimited). All processing happens in your browser — files never reach a server.
Drop your mono file
Choose duplicate or pseudo-stereo widening
Download the stereo result
0 bytes uploaded. Mono to Stereo Converter runs entirely in your browser using FFmpeg.wasm 8.1, RNNoise, and the Web Audio API. Your audio stays on your device at all times. No data is sent to any server — critical for sensitive interviews and confidential calls.
No — true stereo requires multi-mic recording. This duplicates the mono signal (or applies a Haas-effect widener for perceived width).
Separate left and right channels from a stereo recording. Useful when each channel is a different mic.
Open toolConcatenate MP3, WAV, FLAC, M4A files end-to-end. Optional crossfade between tracks. All processing local.
Open toolSmooth out loud and quiet passages so voices sit consistently in the mix. Broadcast-style compression with adjustable threshold, ratio, attack, and release.
Open tool