Stereo to Mono Converter: Audio Downmix
A stereo to mono converter merges the left and right channels of a recording into a single channel. That is handy for voice recordings, podcasts, old music files and speakers or hearing devices that play one channel only. This tool decodes your file in the browser, lets you choose how to combine the channels, and warns you if the two channels are out of phase, which can make a mix sound thin or silent. Preview the result, optionally normalize the volume, and download a mono WAV or a dual-mono stereo file.
Stereo to Mono Converter
Convert stereo audio to mono online. Mix both channels or keep only left or right, then download a WAV file.
How to use the Stereo to Mono Converter
- Choose or drop an audio file (MP3, WAV, M4A, OGG or a video).
- Pick how to combine the channels: average, left only, right only, -3 dB sum or side.
- Check the phase message under the controls and play the result.
- Press Download WAV.
Features
- Average, left only, right only, -3 dB sum and side (L minus R) modes
- Phase check that warns about cancellation
- Output a true mono file or dual mono (two identical channels)
- Optional normalize to prevent quiet results
- Waveform, peak and level readout
- No upload, all in your browser
Frequently asked questions
What does stereo to mono do?
It combines the left and right channels into one. With the average mode every output sample is (left + right) / 2, so both sides are heard equally in one channel.
Why does my mono file sound quiet or hollow?
If the two channels are partly out of phase, they cancel when added together. The tool shows the left and right correlation. If it is below zero, try Left only or Right only instead of Average.
What is dual mono?
It is a stereo file whose left and right channels are identical. It sounds mono but works on players and editors that expect two channels.
Which mode should I use?
Use Average for most music and voice. Use Left only or Right only if one channel is cleaner, or if the average cancels. The -3 dB sum mode keeps a louder result for uncorrelated channels.
Is the file uploaded anywhere?
No. The audio is decoded and converted in your browser, and the WAV is created locally.