by Rick Chinn
Rick will help you understand the proper used of pads used in traditional impedance-matched systems.
Attenuation (loss) pads are handy tools, and understanding their design and application takes a few minutes and lasts a lifetime. We’ll divide this discussion into two parts. The first part discusses pads to be used in traditional impedance-matched (power-based) systems, the second part discusses pads used in voltage-based (bridging) systems. Finally, we’ll go through some construction techniques.
Pads are used anywhere within a system where you need to reduce a signal by some finite amount. Most commonly, this might be between a microphone and its preamp to prevent the preamp from clipping on loud signals. Another place is between a mixer and a power amp to absorb excess gain and to let the mixer operate in a better place from a signal/noise standpoint as well as matching the clip point of the mixer to that of the power amp. In loudspeaker systems using passive crossovers, L-pads are often used to equalize the outputs of the drivers used for each frequency band and to allow rudimentary voicing.