Bandwidth in octaves (or Hz when bwtype=bwh)
Optionalwidth_Width type: o=octave, q=Q-factor, h=Hz, k=kHz, s=slope
Gain in dB, -900.0 to 900.0
OptionalchannelsPlane filter flags
OptionalpolesNumber of poles, 1 or 2. Default: 2
OptionalmixMix between original and filtered signal
Center frequency in Hz