How To Build Your Own Electronic Kit
The Nervous System
Triggers are the nerves of the kit. They sense the impact of the stick or beater and send a signal to the drum brain for processing. The simplest trigger can be created from a piezo transducer, which is available (encased in plastic) at RadioShack, unsheathed from an electronics vendor such as Mouser, or from an online electronic drum resource. The piezo pickups usually have a red wire soldered to the central crystal, and a black wire soldered to the outer metallic ring, but if the piezo is not yet terminated, you’ll have to solder leads onto them yourself with 20awg wire. The red and black leads get soldered to either the tip and sleeve of a 1/4" jack, or directly to the hot conductor and shield of a typical instrument cable that plugs into the brain’s trigger inputs.
Considerations when setting up the triggers include: increasing surface space for even response, isolation from extraneous vibrations to prevent double or false triggering, and protection of the delicate piezo element. The approach you take depends on the playing surface. Since Jake opted for mesh heads on Rototoms and old drum shells, he adopted the Roland approach of mounting the piezos to a metal surface and sticking foam cones on top of them. The foam cones get positioned so that they press against the underside of mesh heads to pick up the stick attack.
If you’re retrofitting a rubber pad or Remo practice kit setup, gluing the piezo to a thin, larger diameter flat disc increases the response area of the surface and effectively transmits the vibration of a stick hit to the pickup more evenly at a wider radius. Thin sheet metal cut to size is common, but some folks have used old CDs and even plastic plates quite successfully. The delicate element must then be isolated from stick hits by a protective layer of foam or rubber. The peizos only need one impulse to trigger. The continuous rippling of resonance or vibrations from adjacent pads could confuse the brain and result in false triggering (not exactly a natural sound). With this in mind, deadening resonances and isolating from extraneous vibrations by utilizing foam and rubber insulation is essential.
An acoustic kit has a wide palette of sound options, such as side sticking on the snare, a bell sound on the cymbal, open and closed and everything in between on the hi-hat, and more. Strategically implementing two triggers on the snare or even up to three triggers on the hi-hat and cymbals can result in a more realistic playing experience by allowing for natural-sounding variations when coupled with a well-featured brain.
Sewing It All Together
Once you’ve gathered all your parts, the first step is to prepare them for assembly. You’ll want to be sure to make the correct measurements before you start drilling holes for any modifications, such as attaching the bass drum spurs and accommodating mounts for the triggers. This episode focuses on Jake’s operating table as he put together his Franken-kit. The approach will be a bit less involved if you choose the flat-pad triggering method.
To begin, Jake installed the bass drum spurs on the “kick” tom. He planned on implementing a four-spur design to support the 12" tom above the ground. But another approach is to fashion a base out of wood that can be bolted to the bottom of the batter-side of the tom. This allows the pedal to be fastened to the drum in the correct position so that the batter hits the center of the head. Some experienced builders recommend using a section of a regular wooden bass drum hoop for use as a support and to anchor the pedal. Simply attach the section via long bolts to the underside edge of the drum.
Install the L-brackets on the “kick drum” and the snare to accommodate the crossbeam by first loosening the nut and washer on the lower of the two lug screws. Attach the L-bracket, replace the washer and nut, and tighten it down. Use the lugs laterally opposite each other on the snare drum, and adjacent lugs on the kick drum.
Now it’s time to measure and cut the metal bars you’ll be using as the crossbeams for the snare and kick drum. Using a hacksaw and a vice is the simplest way to do this. Mark the bar carefully so that it lines up with the L-bracket hole, and drill the holes. Then drill a hole in the middle of the bar and drill three smaller holes around it to accommodate the T-bolt and three screws to reinforce the assembly. The T-bolt will be the base for the trigger.
Use tin snips to cut out the metal discs upon which you’re going to mount the two piezos for the snare, as well as the one for the kick drum. This takes a bit of effort and the metal edges will be sharp, so it’s advisable to wear gloves. Jake used a thin but sturdy sheet of bronze. You want the discs to be slightly wider than the piezos themselves, which reinforces the pickup as well as increases its surface space. He also cut out a piece of bronze big enough to cover the playing area of his makeshift hi-hat pad.
Carve out moderately dense foam rubber discs to fit under the piezos and for insulating washers for metal-to-metal contact points. Then take the 3/8" auto tubing meant to insulate the rims and reduce vibrations, and cut it to length so that each piece can perfectly cover the circumference of each rim. Slit the tubing along its length. To make this easier, drill a 3/8" hole in a 2x4 piece of wood, and then drill through the end of the 2x4 to the hole so that you can insert a razorblade or Exacto knife. Clamp the wood to a table edge and run the tubing through the hole to slice evenly along the length (Fig. 1).