Next you’re going to mount the bar to the L-brackets. The snare beam should be centered, but the bass drum beam will be across the top section of the drum. Now go ahead and install the T-bolt in the middle of the snare and kick drum crossbeams so that the T-bolt protrudes upwards toward the batter-side of the drum. Be sure to use rubber washers between the beam and the screws and nuts. Jake devised the insulated T-bolt approach for greater isolation.
Solder the leads to the piezos if they aren’t already terminated: red wire to the outside area of the central element, and the black wire to the metallic edge. Glue the piezos metallic side down to the bronze discs that you prepared for the two snare triggers and the kick drum, and then use double-sided adhesive tape to fix the cone over the top of the piezo with the leads protruding out the side.
On both the snare and the kick drum T-bolts, glue a 1/4"-thick piece of foam rubber to the little round platform at the top, and then glue the disc/piezo/cone assembly on top of that. Make sure it’s secure. The cone should protrude about an eighth-inch above the bearing edge of the drum so that the mesh head will provide a bit of pressure. Place a ruler or similar flat object across the rim of the drum and eyeball the height of the cone. When the head is tightened down, the cone should displace the head upwards about a sixteenth of an inch. To attach the second “rimshot” trigger to the snare drum, simply glue a piezo directly to the crossbeam near the shell of the snare drum. This trigger will pick up the side sticking and rimshots.
Solder the piezo leads to the TS or TRS jacks (red to tip, black to sleeve) or directly to the cable (red to center conductor, black to shield). Be sure to figure out a good way to manage the cables by either securing them to the rack or stands with Velcro, or installing the jack directly into the shell of the drum if that’s feasible. Taming extraneous vibrations is key to controlling false triggering, so you can further isolate the bass drum shell by using an internal dampener or a thick piece of foam jammed into the cavity of the bass drum and pushed up against the head.
Setting up the Rototom triggers is pretty straightforward compared to the snare and bass drum experience, in that you’ll only be mounting the piezo directly to the center of the upper spoke. First, pad the center of the upper spoke with a 1/4" layer of foam rubber, and then put the head on. Measure the distance between the rubber pad and the head from underneath the drum, and add an extra eighth of an inch. Shear away the top of the cone so that its height matches that measurement. Then test it by putting the trigger with the shorn cone in place and reattaching the head to make sure it’s where it needs to be. Once you’re satisfied with the placement and pressure, glue everything down.
For the final touch on the drum pads, take lengths of 3/8" slit auto tubing and slide them over each of the rims of the toms, snare, and kick to cover the circumference. Glue the ends together so that each rim edge is neatly and completely padded with the rubber surface. Now you’re ready to attach the heads and rims and tune them up nice and snug so that the triggering is sufficient and the action feels good.
Last but not least on the assembly list are the cymbals and hi-hat. Jake used a set of Pintech practice cymbals and glued a layer of foam rubber over the striking area. After soldering each pair of piezo leads to a 1/4" jack, he then stuck a piezo to the underside of each cymbal with thin, double-sided foam tape, about halfway between the bell and the edge and just inside the little rectangular impression. You may opt to get more involved and go for two or three pickups to get edge, bow, and bell sounds. If you decide to use more triggers, make sure the brain you choose has enough inputs and features to handle it.
For a rough and simple hi-hat, Jake made a pad from a 12" disc of wood. He glued the piezo to the center of a 6" bronze disc, making sure the piezo made good contact with the disc, and soldered the leads to a 1/4" jack. He then glued a 3/8" layer of open-cell foam rubber over the wood disc, and glued the bronze plate to that so the piezo leads extended off to the back end of the disc. Over this he adhered a 1/4"-thick piece of Sorbothane (a visoelastic urethane similar to foam rubber). While this setup works sufficiently, it doesn’t provide for switching between open and closed hi-hat sounds, or any other variation.
Jake plans to go back and make a variable-control hi-hat, which can be done using either a simple switch/potentiometer assembly or a fairly straightforward fader device set up with a spring and a wire that attaches to a foot pedal on a traditional hi-hat stand. You could use plastic practice hi-hats or cheap brass hats to which you’ve glued a layer of rubber padding. This setup gives you a more realistic feel. The spring keeps the fader in the open position, and stepping on the pedal pulls the fader down, varying the voltage and therefore the hi-hat sound.
One thing to keep in mind is that a drum module’s variable hi-hat input wants to see a certain resistance value to work properly, and that value can vary between manufacturers. You may need to modify the fader/potentiometer you use to accommodate the requirements of the module. This is a simple procedure that involves soldering a resistor in parallel with the fader to achieve the desired load (per Ohm’s Law).
Once all the parts of the kit are assembled, attach everything to the frame. If you’re using a ready-made frame, you can employ the brackets to mount your pads. If you’ve made your own frame, use U-bolts and clamps and fashion mounts to attach your drums and cymbals. Traditional hardware can also be employed to get the kit standing steady and ready to play.