Simple Explanation

Turning multispeaker surround sound into regular stereo so it can play on two speakers or headphones.

Concise Technical Definition

The process of converting a multichannel audio mix (e.g. 5.1 or 7.1) into a stereo or mono format by algorithmically combining the channel information while preserving as much spatial intent as possible.

Layman-Friendly Analogy

Like shrinking a full orchestra into a duet—you keep the music, but it’s simplified to fit fewer players.

Industry Usage Summary

Downmixing is common when playing surround-encoded content (like Blu-rays or Dolby Atmos streams) on devices that only support stereo output—like TVs, laptops, or phones. AV receivers, software players, and streaming apps handle this automatically.

Engineering Shortcut

Channel-reduction process: multichannel → stereo or mono mix.

Full Technical Explanation

Downmixing is the signal processing method used to convert a multichannel audio format (such as 5.1, 7.1, or Dolby Atmos) into a lower channel count, usually stereo (2.0) or mono (1.0). It combines individual speaker channels using predefined gain and phase rules to preserve as much of the original spatial and tonal balance as possible. This is especially important for compatibility with legacy or mobile playback systems. Proper downmixing prevents overload, phasing issues, or dialogue loss and may include specialized matrices like Dolby Surround Downmix or ITU-R BS.775 standards.