Amplifier Input High Pass Filter Calculator

This calculator can help with the capacitance needed for a capacitor,
to engineer a passive high pass filter for e.g. subwoofer integration.
Uses formula C = 1/(2*π*Zin*f3)


1. Enter amplifier input impedance (Zin) in Ohms:

2. Enter desired -3dB cutoff frequency(f3) in Hertz:

Enter valid numeric values to





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Wiring example drawing, borrowed from Troels Gravesen, Denmark.
Keep in mind, since audio signal is AC, you'll want a bipolar/non-polarized capacitor.