These square drums also use a kind of drum head that does not need tensioning, which is unusual for drums. I make them out of x-ray film material and silicone rubber. They are easy to make. The individual drums are then glued into clusters using more silicone.
The sound it makes is pretty nice. Hear it in the last step.
Step 1: Cutting the Pipes
Without knowing what notes I was going to get, I established the longest pipe, the shortest pipe, and divided the lengths of the other pipes in equal steps between those two end pipes. There were twelve pipes, and I numbered them 1-12. Uniform length changes seems to make for uniform sound changes, so I imagine a similar set of drums could be tuned to standard notes, if one had known starting and end points with appropriate length intervals to get the desired sound intervals.
In cluster one, I used pipes 1,4,7 and 10. In cluster two, I used pipes 2,5,8 and 11. In cluster three, I used pipes 3,6,9 and 12. All the clusters are arranged in the same sort of counter-clockwise pattern of short to long pipe lengths so that repeating the pattern in each cluster will repeat the same sound pattern, only shifted up or down the scale a little.
Step 2: Making the Heads
When the silicone is dry and the film is stuck down, trim off the excess film material with scissors.
Then, squirt some more silicone over the surface of the drum head and build up about an 1/8 inch thick layer. I use a sort of square spiral pattern, working to the center from the outside. Go over the outside edge of the film and down the side of the pipe about 1/2", to help it adhere to the pipe better. When that hardens up, I use a palette knife, like a little trowel, to spread on a little more and smooth off the silicone surface.
The bare, un-tensioned x-ray film doesn't sound very good to my ear. For some reason, the silicone layer improves the sound. My guess is that a tensioned drum head has stiffness and elasticity. In these un-tensioned heads, the stiffness seems to come from the x-ray film and the elasticity comes from the silicone layer. That's just my guess. There may be a scientific explanation for it.
Step 3: Assembling the Drum
When that dries, you are ready to start playing. You can play with your fingertips, or with drumsticks. My favorite drumsticks use a handle, metal or plastic, with a silicone covered end. On bigger drum mallets I sometimes mix in some ground up styrofoam as light-weight filler material in the silicone.
Step 4: Some Other Cluster Drum Variations
Step 5: Listen to the Sound of Cluster Drums
Click on the icon that looks like a dog-eared piece of paper to open the MP3 audio file.