Piezo tweeters are used in many sound reinforcement applications and musical instrument cabinets because, among professionals, they have a reputation for low cost and reliability. Arrays, usually vertical to maintain horizontal dispersion, are common. Piezos present a purely capacitive load to an amplifier and operate on voltage rather than current. The best way to use Piezos is with a shunt resistor and crossover capacitor of sufficient voltage to handle the amplifier's output; matched together to set the crossover at a certain frequency for smooth sound.
Things you need
Group of piezo tweeters
22-ohm, 100-watt shunt resistor
1.6 µF, 100-watt polypropylene capacitor
100-watt, 8-ohm L-pad
Liquid solder flux
Cut, split, and strip 3/4 inch of insulation off the ends of enough speaker wire for each tweeter to reach from them to a single point. Solder positive wires to positive tweeter terminals and negative wires to negative terminals. Bring them all to a central point.
Twist together all positive wire ends. Twist together all negative wire ends. Solder the resistor between the positive and negative wire ends. Solder one capacitor lead to the positive connections. Since the tweeters are purely capacitive, the amplifier will react only to the resistor as impedance for setting the crossover at 4,500 Hz. with the capacitor.
Lay the L-pad on its back with the terminals facing you. Connect the left terminal with the negative wires of the tweeters and the negative amplifier feed. Connect the middle terminal to the loose end of the capacitor. Connect the right terminal to the amplifier positive speaker lead.
Things you need
- Group of piezo tweeters
- 22-ohm, 100-watt shunt resistor
- 1.6 µF, 100-watt polypropylene capacitor
- 100-watt, 8-ohm L-pad
- Speaker wire
- Soldering iron
- Liquid solder flux