looks like a 18 inch bass drum......

The set up looks to me like 8x8" and 8x10" toms over 8x12" and 8x13" toms over a 14x18" bass drum. Then, there is a conventional 14x14" or 16x16" floor tom, too. I have seen similar configurations---usually with a 22" or larger bass drum. This rig offers a lot of drummage in a small footprint. There are at least two--maybe three drums too many for me. But, I can see more talented and more adventurous drummers than I making this drum set work for them.

Mounting more than two toms on a bass is not as uncommon as you'd think. Rogers' Memriloc mounts were designed to do exactly that (first pic below). In the era of big hair and huge sets, many rockers accomplished this just by adding another mount in front of the stock double-tom mount (Neil Smith's Premier kit below). And were three mounted toms ever offered on a stock catalog set?... Take a look at the Slingerland Avante set from the 1973 catalog.

[Attachment: 64910] [Attachment: 64911] [Attachment: 64912]

Here's a Ludwig add from Modern Drummer Nov. '82. It's ironic that the heading of this thread is "Unusual Set Up" and the name for the mounting system was called "The Set Up".

Guess I need longer arms......or drum sticks!DOHYes Sir