a scanline maximum is not an audio waveform

The earlier audio transport sampled registers by scanline and retained the largest AUDV value observed before the next snapshot. That prevented silence when a game raised and cleared volume between WSYNCs, but it also changed every ordered transition: \12 -> 0\ became volume 12 for the entire scanline, and multiple AUDC/AUDF writes collapsed to whichever values happened to survive.

Raw traces, ROM material, local paths, and personal data are not part of this public record.