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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;;;
;;; Banded Waveguide Instrument based on
;;; ====== =========
;;;
;;; Essl, G. and Cook, P. "Banded
;;; Waveguides: Towards Physical Modelling of Bar
;;; Percussion Instruments", Proceedings of the
;;; 1999 International Computer Music Conference.
;;;
;;; Also, Essl, Serafin, Cook, and Smith J.O.,
;;; "Theory of Banded Waveguides", CMJ, 28:1,
;;; pp37-50, Spring 2004.
;;;
;;; NOTES:
;;; As with all physical models, initial conditions matter.
;;; Frequency range is not too broad. 220Hz. is a good
;;; starting point.
;;;
;;;
;;; Tuned bar, Glass Harmonica and Uniform Bar for now.
;;;
;;; 08/22/2013 update bandpass filters with CLM's filter generator (juanig)
;;; 08/24/2013 replaced delay line macros with DelayL using clm's delay ug
;;; 08/29/2014 fixed waveguide with feed and reflections
;;; 08/30/2014 Try different delay line lengths. Fixing bandpass radius param.
;;; 09/04/2014 This SND's S7 version
;;;
(define* (make-bowtable (offset 0.0) (slope 1.0))
(float-vector offset slope))
(define (bowtable b samp)
(max 0.0 (- 1.0 (abs (* (b 1) (+ samp (b 0)))))))
(define (make-bandpassbq freq radius)
(let ((arra (make-float-vector 3))
(arrb (make-float-vector 3)))
(set! (arra 1) (* -1.998 radius (cos (hz->radians freq))))
(set! (arra 2) (* radius radius))
;;;
;;; gain gets normalized
;;;
(set! (arrb 0) (- 0.5 (* 0.5 (arra 2))))
(set! (arrb 2) (- (arrb 0) ))
(make-filter 3 arra arrb) ))
;;; To handle bandpass filter
(define (bandpassbq f sample0)
(filter f sample0))
;;; Delay line structures and functions using SND's delay generator (as per prc95.scm)
(defgenerator dlya (outp 0) (input #f))
(define (make-delayl len lag)
(make-dlya :input (make-delay len :max-size (ceiling (+ len lag 1)))
:outp (- lag len)))
(define (delayl d samp)
(delay-tick (d 'input) samp)
(tap (d 'input) (d 'outp)))
;;;;;;;;;;;;;;;;;;;;
(definstrument (bandedwg beg dur freq amplitude
;; vibration modes
;; 1=tuned Bar; 2=Glass Harmonica;
;; 3= Uniform bar
(mode 3)
(maxa 0.9998) ;; max bow velocity
(bv 1.0) ;; bow velocity scaler
;; velocity envelope
(vel-env '(0 1.0 .95 1.1 1 1.0))
(amp-env '(0 1 1 1)) ;;'(0 0.0 .95 1.0 .99 0.00))
(rev-amount .08) )
(let ((nrmodes 4))
(cond ((= mode 1)
(set! nrmodes 4))
((= mode 2)
(set! nrmodes 6))
(else
(set! nrmodes 4))
)
(let* ((start (seconds->samples beg))
(baselen (/ *clm-srate* freq)) ;; original Stk delayl length
(baselag (- (/ *clm-srate* freq) 0.5))
(dtapoffs 0.0) ;; tap offset is 0.0 in StK's version
(bandpass (make-vector nrmodes))
(delayslft (make-vector nrmodes))
(delaysrfl (make-vector nrmodes))
(modes (make-float-vector nrmodes))
(gains (make-float-vector nrmodes))
(basegains (make-float-vector nrmodes))
(excitations (make-float-vector nrmodes))
(delastout (make-float-vector nrmodes))
;;
(fradius 0.0) ;; radius for bandpass filter
(dlength 0.0) ;; delay-line length
(dlag 0.0) ;; delay lag (for tap)
;;
(bowtab (make-bowtable :slope 3.0 :offset 0.001))
(ampenv (make-env amp-env :scaler amplitude :duration dur))
;; (vel-env (make-env vel-env :scaler bv :duration dur))
;;
(maxvelocity maxa)
(end (+ start (seconds->samples dur)))
)
;;
;;
(cond ((= mode 1) ;; Tuned Bar
(begin
(set! (modes 0) 1.000)
(set! (modes 1) 4.0198391420)
(set! (modes 2) 10.7184986595)
(set! (modes 3) 18.0697050938)
(do ((i 0 (+ i 1)))
((= i nrmodes))
(set! (basegains i) (expt 0.998 (+ i 1)))
(set! (excitations i) 1.0) )
))
((= mode 2) ;; Glass Harmonica
(begin
(set! (modes 0) 1.000)
(set! (modes 1) 2.32)
(set! (modes 2) 4.25)
(set! (modes 3) 6.63)
(set! (modes 4) 9.38)
(set! (modes 5) 12.22)
(do ((i 0 (+ i 1)))
((= i nrmodes))
(set! (basegains i ) (expt 0.988 (+ i 1)))
(set! (excitations i) 1.0))
))
(else ;; Uniform Bar
(begin
(set! (modes 0) 1.000)
(set! (modes 1) 2.756)
(set! (modes 2) 5.404)
(set! (modes 3) 8.933)
(do ((i 0 (+ i 1)))
((= i nrmodes))
(set! (basegains i ) (expt 0.9 (+ i 1)))
(set! (excitations i) 1.0))
))
)
;;
;; set-frequency method in STK's BandedWG
;;
;; (set! fradius (- 1.0 (* pi (/ 32 *clm-srate*))))
(set! fradius (- 0.3998 (* pi (/ 32 *clm-srate*))))
(do ((i 0 (+ i 1)))
((= i nrmodes))
(set! dlength (floor (/ baselen (modes i))))
(set! dlag (floor (/ baselag (modes i)))) ;; (- lag len) --> tap offset
(set! (delayslft i) (make-delayl dlength dlag))
(set! (delaysrfl i) (make-delayl dlength dlag))
(set! (gains i) (basegains i))
(set! (bandpass i)
(make-bandpassbq (* freq (modes i)) fradius)) )
;;
;;;;;;;;;;;;
;;
(do ((i start (+ i 1)))
((= i end))
;;
(let ((input 0.0)
(velinput 0.0)
(bowvelocity 0.0)
(bplastout 0.0)
(dlastsampl 0.0)
(outsampl 0.0)
)
(do ((k 0 (+ k 1)))
((= k nrmodes))
(set! velinput (+ velinput (* (basegains k) (delastout k))) )
)
;;
;; (set! bowvelocity (* 0.3 (env vel-env) maxvelocity))
(set! bowvelocity (* 0.3 maxvelocity))
(set! input (- bowvelocity velinput))
(set! input (* input (bowtable bowtab input)))
(set! input (/ input nrmodes ))
;;
;; Here the waveguide
;;
(do ((j 0 (+ j 1)))
((= j nrmodes))
(set! bplastout (+ bplastout (bandpassbq (bandpass j)
(delayl (delayslft j)
(+ input (* (gains j) dlastsampl)) ))))
(set! dlastsampl (+ dlastsampl (delayl (delaysrfl j) bplastout)))
(set! (delastout j) dlastsampl)
)
;;
;;
(set! outsampl (* 4.0 (env ampenv) bplastout))
(outa i outsampl)
;;
(if *reverb*
(begin
(outa i (* outsampl rev-amount) *reverb*)))
)))
))
;;; (with-sound () (bandedwg 0 1 220 0.4))
;;; (with-sound () (bandedwg 0 1 220 0.4 :mode 1))
;;; (with-sound () (bandedwg 0 1 220 0.4 :mode 2))
;;; (with-sound () (bandedwg 0 1.0 220 0.7 :mode 1 :maxa 0.497))
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