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Toot 5: Vibrato

To add some delayed vibrato to our chorusing instrument we use another oscillator for the vibrato and a line segment generator, linseg, as a means of controlling the delay. linseg is a k-rate or a-rate signal generator which traces a series of straight line segments between any number of specified points. The Csound manual describes it as:
     kr   linseg    ia, idur1, ib[, idur2, ic[...]]
     ar   linseg    ia, idur1, ib[, idur2, ic[...]]
Since we intend to use this to slowly scale the amount of signal coming from our vibrato oscillator, we'll choose the k-rate version. The i-rate variables: ia, ib, ic, etc., are the values for the points. The i-rate variables: idur1, idur2, idur3, etc., set the duration, in seconds, between segments.
   instr 5                            ; toot5.orc
     irel = .01                           ; set vibrato release time
     idel1 = p3 - (p10 * p3)              ; calculate initial delay (% of dur)
     isus   = p3 - (idel1- irel)          ; calculate remaining duration
     iamp = ampdb(p4)
     iscale = iamp * .333                      ; p4=amp
     inote = cpspch(p5)                        ; p5=freq
     k3     linseg    0, idel1, p9, isus, p9, irel, 0  ; p6=attack time
     k2     oscil     k3, p8, 1                ; p7=release time
     k1     linen     iscale, p6, p3, p7       ; p8=vib rate
     a3     oscil     k1, inote*.995+k2, 1     ; p9=vib depth   
     a2     oscil     k1, inote*1.005+k2, 1    ; p10=vib delay (0-1)
     a1     oscil     k1, inote+k2, 1
            out  a1+a2+a3
   endin     
     
        f 1  0  4096  10  1
; ins strt dur  amp  frq       atk  rel  vibrt   vibdpth  vibdel
  i5  0    3    86   10.00      .1  .7   7       6       .4
  i5  4    3    86   10.02      1   .2   6       6       .4
  i5  8    4    86   10.04      2   1    5       6       .4
 e
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Toot Contents
Prepared from the MIT Media Lab Csound Manual, PJN, Nov 1994.