Stereo to Mono
Fold a stereo file down to a single channel, which suits speech and saves space.
MP3, WAV, M4A, FLAC, OGG, Opus, AIFF, WMA, AMR and the sound of most videos. Files stay on your device.
How it works
- Choose an audio file.
- Pick Mix both, Left only or Right only.
- Preview the result.
- Export and download.
Three ways to get one channel
Mix both adds left and right into a single channel. Average halves each side before adding (6 dB down each), so the result can never clip and sound that is the same in both channels keeps its level. Sum at −3 dB each is louder: identical channels come out 3 dB louder than before, which can clip. Left only and Right only keep one side and drop the other, which is what you want when one side holds the recording and the other is silent or noisy.
Files with more than two channels are averaged into one when mixing.
When mono is the right choice
Speech recordings gain nothing from stereo. A mono file is about half the size of a stereo file at the same quality, so it saves space and bandwidth, and it plays identically on every speaker and phone. Music loses its sense of width in mono, so keep stereo for music unless you have a reason.
If the two channels are out of phase, mixing them cancels sound and parts of the recording go quiet or vanish. Preview the result; if something is missing, keep one side or flip the polarity of a channel in the channel mixer first.
Output
The result is a single-channel file in the format you choose. WAV, FLAC and AIFF are lossless; lossy formats are encoded once more. The channel count follows this tool, so the Output settings do not offer a channel option.
Questions
Will converting to mono lower the quality?
The audio quality of each remaining sample stays the same, but the stereo image is gone. Lossy formats are encoded again, so use a high bitrate or a lossless format if you will keep editing.
Why did part of my recording disappear in mono?
That is phase cancellation: some content was stored with opposite polarity in the two channels, and adding them cancels it. Use Left only or Right only, or invert one channel with the channel mixer before mixing.
Which mix level should I use?
Average is safe and keeps the level. Use the −3 dB sum if the result sounds too quiet, and check the preview for clipping.
Does it halve the file size?
For uncompressed WAV, yes. For MP3 and other lossy formats the size depends on the bitrate you choose; a mono file at half the bitrate is about half as large.