View Full Version : L-Pad vs. Toggle Switch

04-22-2005, 02:12 PM
When building a crossover for JBL mid's and hi's, what is a toggle switch and what numerical specification's do they use to describe them including separate quality resistor's to adjust the impedance?

04-22-2005, 07:54 PM
"Toggle" switch merely denotes a switch with a projecting lever. One that is double-pole may be used to select between two resistor pairs comprising different attenuation circuits.

While "L-Pad" usually refers to a variable attenuation control, a simple two-resistor circuit configured for fixed attenuation is an L-Pad as well.

It takes a rotary selector to switch among more than two fixed-resistor attenuations, or a system of jumpers as is used in some JBL crossovers.

The fixed resistors must be selected so as to maintain a constant impedance in combination with the driver being attenuated:

Play a bit at #122 here to understand resistive attenuation: