dr. colossus, I agree that a single headed drum does produce tone - and yes Roto Toms are tonal.
Perhaps I should have referenced overtones or as you indicate harmonics. I was a very big fan of Bill Ward (and early Sabbeth) in fact at the time my band did almost nothing but, Sabbath, Grand Funk, Cream & Hendrix), and you are correct that Ward actualy did have more of an open sound than many at the time - I'm sure a reflection of his jazz roots.
As you said, we're saying the same thing, perhaps just different terminology.