Okay, so I just ran the Oscilloscope app on my Android tablet while playing Daren’s 13 Melodica Comparison. This is pretty basic stuff for many here, I know. The melodicas are accompanied for all thirteen entries, of course, but the accompaniment is the same. I don’t know much about interpreting oscilloscope readings, but there are obvious differences for the thirteen, and some of them are more alike than others. Same with the handful of melodicas I have here on my desk. The flattest Middle C readings are for my hybrid Yamaha P-37E, which also sounds the most muted (in the sense in which I understand that term). The Suzuki M-37C has more highs and lows. Closer to the Yamaha, though with slightly more pronounced highs and lows, is a first generation (small key) Hohner Piano 27. I regard the Piano 27 as more muted than most melodicas, and these readings are indicative of how muted my P-37E is.
Now for Andre’s Scala Scaletta/Yamaha P-32D comparison: The readings from Andre’s comparison are remarkably close for the two instruments. I’m guessing that a closer comparison of the oscilloscope readings by a more informed reader would shed light on what makes for the differences Daren and I hear (and disagreed about).
I’m now remembering that I have seen reference to such technicalities in a Japanese blog.