Stereo field behaviour
How energy is distributed and moves between the left, right and side channels.
Average stereo width is nearly useless for detection — it is a mixing decision. What carries information is how the side channel behaves over time relative to the mid channel.
A recording made with real microphones in a real space has correlated, physically plausible movement: a room reflects, instruments occupy positions, reverb decays into the sides. Synthesised stereo can be plausible too, but it is often produced by a widening process applied uniformly, which shows up as side-channel energy that tracks the mid channel too closely or too evenly.
How this tool uses it
Mid/side energy ratios are computed per window; the variability of that ratio across windows is the feature, not the average.
What else produces the same reading
- Stereo wideners and mid/side processing on human mixes.
- Mono or near-mono sources of any origin.
- Upmixed mono, which produces artificial but human-authored stereo.