reslp.lsp
 Version 1.00  31 October 2004
 Author Steven Jones

 Contact jones57@swbell.net include the word "nyquist" in subject line

 The contents of this file are released under the terms of the GNU General
 Public License. See the file LICENSE.txt

 Low and high pass filters with resonant peak.  The filters are constructed
 by using the non-resonant lp(hp) function in parallel with reson.

function

 (reslp sig ctrl [:bw][:mix][:n])
 Lowpass filter with resonance.  The filter is constructed by placing lp and
 reson in parallel

 sig    - sound. The source signal.

 ctrl   - sound or flonum. The cutoff frequency.

 :bw    - flonum. The reson filter band width in Hz

 :mix   - flonum or sound. The relative contribution between lp and reson to
          the results, 0 <= mix <= 1.  For mix = 0 the result is pure 
          low-pass, for mix = 1 the result is pure band pass.  
          Default n=0.5

 :n     - integer. The n argument to reson. See documentation for reson,
          default n=1

 return - sound.

function

 (reshp sig ctrl [:bw][:mix][:n])
 Highpass filter with resonance.  The filter is constructed by placing hp and
 reson in parallel

 sig    - sound. The source signal.

 ctrl   - sound or flonum. The cutoff frequency.

 :bw    - flonum. The reson filter band width in Hz

 :mix   - flonum or sound. The relative contribution between hp and reson to
          the results, 0 <= mix <= 1.  For mix = 0 the result is pure 
          high-pass, for mix = 1 the result is pure band pass.  
          Default n=0.5

 :n     - integer. The n argument to reson. See documentation for reson,
          default n=1

 return - sound.

;; reslp.lsp
;; Version 1.00  31 October 2004
;; Author Steven Jones
;;
;; Contact jones57@swbell.net include the word "nyquist" in subject line
;;
;; The contents of this file are released under the terms of the GNU General
;; Public License. See the file LICENSE.txt
;;
;; Low and high pass filters with resonant peak.  The filters are constructed
;; by using the non-resonant lp(hp) function in parallel with reson.
;; 

(require 'xmix)
(provide 'reslp)
(current-file  "reslp")


;; @doc function reslp
;; (reslp sig ctrl [:bw][:mix][:n])
;; Lowpass filter with resonance.  The filter is constructed by placing lp and
;; reson in parallel
;;
;; sig    - sound. The source signal.
;;
;; ctrl   - sound or flonum. The cutoff frequency.
;;
;; :bw    - flonum. The reson filter band width in Hz
;;
;; :mix   - flonum or sound. The relative contribution between lp and reson to
;;          the results, 0 <= mix <= 1.  For mix = 0 the result is pure 
;;          low-pass, for mix = 1 the result is pure band pass.  
;;          Default n=0.5
;;
;; :n     - integer. The n argument to reson. See documentation for reson,
;;          default n=1
;;
;; return - sound.
;;

(defun reslp (sig ctrl &key (bw 100)(mix 0.5)(n 1))
  (xmix (lp sig ctrl)
	(reson sig ctrl bw n)
	mix))


;; @doc function reshp
;; (reshp sig ctrl [:bw][:mix][:n])
;; Highpass filter with resonance.  The filter is constructed by placing hp and
;; reson in parallel
;;
;; sig    - sound. The source signal.
;;
;; ctrl   - sound or flonum. The cutoff frequency.
;;
;; :bw    - flonum. The reson filter band width in Hz
;;
;; :mix   - flonum or sound. The relative contribution between hp and reson to
;;          the results, 0 <= mix <= 1.  For mix = 0 the result is pure 
;;          high-pass, for mix = 1 the result is pure band pass.  
;;          Default n=0.5
;;
;; :n     - integer. The n argument to reson. See documentation for reson,
;;          default n=1
;;
;; return - sound.
;;

(defun reshp (sig ctrl &key (bw 100)(mix 0.5)(n 1))
  (xmix (hp sig ctrl)
	(reson sig ctrl bw n)
	mix))