Phase cancellation and clipping
Signals with opposite polarity can partially cancel when combined. The page computes correlation and difference energy from a reduced-rate two-channel analysis in a Worker. When both indicators cross conservative thresholds it says possible cancellation. It does not make an absolute phase diagnosis, because a bounded sample and a simple statistic cannot represent every frequency, time region, or listening condition.
If the warning appears, compare balanced, left-only, and right-only output around the affected passages. A single channel may be safer than averaging. If no warning appears, cancellation is still not impossible. Balanced scaling reduces direct summing gain, while output encoding and the source peak history still determine whether additional clipping or limiting is present.
File-size impact
Mono often improves coding efficiency, but stereo-to-mono conversion does not promise a file exactly half as large. A fixed 96 kbps output remains near the size implied by 96 kbps whether the source was mono or stereo. Container headers, tags, padding, variable-rate decisions, duration, codec, and the selected bitrate all influence actual bytes.
The estimate uses duration multiplied by target bitrate for lossy formats. WAV and FLAC follow different size behavior. The result card reports the actual file size and average bitrate obtained from the produced file, so the selected setting is never presented as a measurement.
When to keep stereo
Keep stereo when location, width, ambience, music panning, binaural capture, audience reaction, or two-channel editing flexibility matters. Archival masters should normally remain in their original channel layout. Make a separate mono delivery copy for a specific voice or compatibility need rather than replacing the only source.
Stereo can also be required by a broadcaster, editor, or distribution specification. Conversely, a platform accepting stereo does not mean stereo is useful for every voice file. Decide from the content and destination. This page provides routing facts, listening controls, and verified output parameters without assigning a quality score.
Practical examples
For a lavalier recorded only on the left, choose left-only so the quiet right channel does not dilute it. For two identical voice channels, balanced mode is a reasonable starting point. For a music bed with intentional width, keep stereo. For two microphones that become hollow when averaged, use the cancellation warning as a prompt to listen and consider one side.
Select a format the destination supports. MP3 is a common preview fallback, M4A/AAC can be efficient, and WAV is predictable PCM but large. Lossy outputs are re-encoded; increasing bitrate cannot restore source detail. All decoding, analysis, downmixing, verification, preview URL creation, and cleanup remain in the browser.