One of the distinctive features of the double trio in 1994 was impressive percussive firepower marshalled by Bill Bruford and newcomer, Pat Mastelotto. Of the new double drum set-up Adrian Belew recalls “There was a running joke in band: ‘How do we have two drummers and not sound like the Allman Brothers?’ Pat and Bill worked very hard on orchestrating all sorts of different possibilities.”

Bruford looks back on the piece with some fondness. "The technical interest in the drums for me was fantastic and great fun and, right there, there was enough of a reason to join King Crimson. Because Pat would be the very solid time keeper, the link between the band and tempo which would enable me to be the terrorist which was great. So I could play the fancy shit and he'd play the bit that connected the fancy shit to the listener. A lovely scenario and a very clear and simple understanding of what the two drummers would be doing and I could work well with that."

The piece is influenced by exercises detailed in the book, Rhythmic Illusions written by Gavin Harrison, and for which Bill provided the foreword. “I sent Bill an early copy of the manuscript to Real World where they were recording Thrak” recalls Harrison “I guess he liked it and it became some influence on the tracks that followed.”
The title is Bruford's pastiche on Max Roache's multi-percussion group M'Boom. "I thought King Crimson should have its own little percussion group on that track — Bill Boom as opposed to Max Boom," remarks a proud Bruford.

Here then are the bare bones of B’Boom, recorded in Real World during the Thrak sessions in 1994: first Bill’s part (complete with 13 second silence), then Pat’s part and finally both of the B’Boom boys together.