Average mixdown sums L and R and divides by 2, which preserves centered content (vocals, kick) but can cause phase cancellation in content recorded in opposite phase. The L and R modes simply discard one channel — useful when only one channel has valid content or to guarantee no cancellation occurs.
Stereo to Mono Converter
Convert stereo audio to mono with precise mixdown control — average, left, right, mid or side channel.
What stereo-to-mono mixdown is and when it matters
Converting stereo to mono seems straightforward, but it involves technical decisions that directly impact the result. The default option — channel average — is the most common, but can destroy content recorded with intentional phase cancellation, such as M/S-encoded drum samples or aggressive stereo effects. This tool decodes the file in the browser using the Web Audio API, applies the chosen mixdown algorithm directly on the PCM samples, and exports without intermediate re-encoding. No data is sent to the server.
Three steps to convert stereo to mono
- Upload your audio file (MP3, WAV, FLAC, etc.).
- Review the L/R channel analysis, phase correlation, and choose the right mixdown mode.
- Click Export and download the mono file in your chosen format.
Sources and references for this tool
These references help contextualize formulas, standards, APIs and limitations used on this page. They do not replace professional validation when a result has legal, financial, medical or operational impact.
- AudioBuffer.numberOfChannels — Web APIsMDN Web Docs — Property returning the channel count of an AudioBuffer — foundation for stereo detection.
- Web Audio API — Upmixing and DownmixingW3C / WebAudio Working Group — Spec section on channel mixing — defines stereo-to-mono downmix equations.
- Pearson Correlation CoefficientWikipedia — Mathematical definition of Pearson correlation used for L/R phase correlation measurement.