true:balance

To account for the human perception of levels in different frequencies, the analyzer uses a perceptually motivated frequency summing that leads to a bathtub-like distribution for pink noise and an upwards slope in high frequencies for white-noise-like signals. Narrow-band signals (e.g. sine waves) will have a constant level across all frequencies.

This weighting helps to better represent critical level differences as perceived by a mixing engineer.

While Mono Check is active, the filter caused by mono-summing will be displayed as an additional yellow line inside the spectrum display. A more or less static filter shape indicates that the mono-summing will lead to spectral problems (e.g. comb-filters), while a constantly varying filter shows that summing to mono will not lead to any static filtering effects.

You can observe the filter while making changes to your mix to monitor the impact on the mono compatibility of your track.

The "diff" value shows the deviation from the center of the reference zone in the respective frequency range, while the Level Check hints show the deviation from the border to the reference zone. Therefore, the changes suggested by the Level Check hints are always a bit smaller than the displayed "diff" values.

While the speech references focus on recordings with one speaker (high or low speech), the podcast references is based on a mixture of low speech and high speech recordings (assuming multiple speakers).