On August 2, 2003, at 2:30 a.m., Phish performed an hour-long, ambient group improvisation at Loring Air Force Base in Limestone, Maine, from the top of an abandoned air traffic control tower.

“White rolls of fabric were dropped, covering the tower,” Elayne Best wrote on fan site Phish.net. “Three dancers from the Bay Area’s Project Bandaloop began performing acrobatics at the top, and then they began to gradually descend in front of projected patterns. The band was able to match the jam to the rhythmic motions of the dancers. This was accomplished via ground-based video cameras and tiny television monitors on top of the tower. Amorphously improvising amidst their own sonic art installation, Phish had once again outdone themselves; leaving behind them a trail of smoke and light in the night sky.”

I was living in Connecticut at the time, and I had no idea this was going on. Nobody I knew even listened to Phish anymore. I can’t remember what was going on in the world, but it was less than two years after 9/11, my son was two and a half and my wife was working as a teacher while I was home with him, trying to finish my dissertation when he napped.

But later I heard about the Tower Jam, and I finally listened to it for the first time a couple of nights ago. I sketched this out on an 18 in. x 24 in. piece of paper as I did, juggling six different colored markers. The width of the sketch, from left to right, represents the length of the improvisation (or 60 minutes; the midpoint of the diagram is roughly halfway through the piece, or 30 minutes). Each color is an interpretation of what one of the players is doing at any given moment. Large letter names (“E,” “A,” etc.) represent tonal centers, usually (but not always) established by the bass voice (Mike, in blue).

There’s a third dimension to this schematic that’s not in many of my other ones: a third, outward-leaning dimension, which occurs around where the first dramatic descending lines occur. At these points, where that vertical dimension is so prominent, the sound gets “stacked” on top of itself. There as a build-up of density; see if you hear that too.

This is only an interpretation of the music, representing the first and only time I’ve ever listened to it. I’m not sure I’ll ever listen again, but probably.

—Michael Hamad

For more of these, visit setlistschematics.tumblr.com.