The history of the deeper bass drum started in 1979 or so. Ludwig introduced a 16" depth bass drum, selling us on the more 'boom' principle because it's deeper, and that's when all this silliness really began. Jeff Porcaro at the time very popular because of that new band he was in, Toto, was constantly in magazine ads with his Pearl power toms and deeper bass drum. (Although I did find it ironic that Stewart Copeland, didn't go to deeper-sized drums for the entire run of the Police. Hmm...). I believe Sonor was really the first to offer the square-sized toms and deeper bass drums. The new depth was just that: new. Up until that time, every manufacturer had basically the same sizes. I suppose it was a cool thing happen, because now there are all kinds of sizes available to folks. You didn't have these size choices at all in the 70s. But having all these choices created the biggest headache for consumers, though!