Filter Slope Comparison Chart
Illustration in preparation Description: Four frequency response curves on same axes showing 6, 12, 18, 24 dB/octave high-pass filters from same crossover frequency; rolloff rates, -3 dB points, and phase shift labeled for each
Attenuation below crossover:
| Slope | 1 octave below | 2 octaves below | 3 octaves below |
|---|---|---|---|
| 6 dB/oct | -6 dB | -12 dB | -18 dB |
| 12 dB/oct | -12 dB | -24 dB | -36 dB |
| 18 dB/oct | -18 dB | -36 dB | -54 dB |
| 24 dB/oct | -24 dB | -48 dB | -72 dB |
Example: 80 Hz crossover, 24 dB/oct slope: - At 40 Hz (1 octave below): -24 dB attenuation - At 20 Hz (2 octaves below): -48 dB — almost inaudible