ToolsElectronics, cables & data
L-pad for loudspeakers
Series and parallel resistor values to attenuate a driver while keeping its impedance.
Ω
dB
- Series resistor
- 2.33643Ω
- Parallel resistor (across the driver)
- 19.3922Ω
- Share of power reaching the driver
- 50.1187%
An L-pad attenuates a driver (typically a tweeter) while the amplifier and crossover still see the nominal impedance. Use resistors rated for the power they dissipate.
How it works
Tweeters are often more sensitive than woofers. An L-pad lowers the tweeter level without changing the impedance seen by the crossover, so the crossover frequency stays where it was designed.
Formulas
- k = 10^(−A / 20)
- R_series = Z · (1 − k)
- R_parallel = Z · k / (1 − k)
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