#lang scribble/manual
@(require (for-label racket))

@title{(sos in a0 a1 a2 b1 b2)}


Second order filter section (biquad).  A standard second order
filter section. Filter coefficients are given directly rather than
calculated for you.

Same as two-pole


@racketblock[
(let* ((theta (line kr (* 0.2 pi) pi 5 remove-synth))
       (rho (line kr 0.6 0.99 5 remove-synth))
       (b1 (mul 2 (mul rho (u:cos theta))))
       (b2 (neg (squared rho))))
  (audition (out 0 (sos (lf-saw ar 200 0.1) 1 0 0 b1 b2))))
]


