[CM] portamento

[James Hearon]

Hi,
I'm still pondering how best to accomplish this.  I tried a couple of exs below, one adding filters.

I thought bandpass was best to try but couldn't get good high cutoff results with just one filter so I went to two overlapping bandpass filters.  But I've buggered the freqs by an octave somehow.  That could have been in using hz->radians as cutoffs.

I think my experiments still sound too glissy overall.

I'm wondering if there are other suggestions?

Thank you,
Jim

;no portamento.
(definstrument (noport start-time duration frequency (amp-env '(0 0 1 1 2 1 3 0)) sampling-rate)
  (let* ((beg (floor (* start-time sampling-rate)))
(end (+ beg (floor (* duration sampling-rate))))
(sine-wave (make-oscil :frequency frequency))
(ampf (make-env amp-env :duration duration :scaler 1.0))
         )
     (do ((i beg (+ i 1)))
         ((= i end))
     (outa i (* (env ampf) (oscil sine-wave )))
     (outb i (* (env ampf) (oscil sine-wave )))
     )))

;portamento. no filter.
(definstrument (myport start-time duration frequency start-freq end-freq (amp-env '(0 0 1 1 2 1 3 0)) sampling-rate)
  (let* ((beg (floor (* start-time sampling-rate)))
(end (+ beg (floor (* duration sampling-rate))))
(sine-wave (make-oscil :frequency frequency))
(ampf (make-env amp-env :duration duration :scaler 1.0))
(frqf (make-env '(0 0 1 1) :scaler (hz->radians (- end-freq start-freq)) :duration duration :base 0.67))
         )
     (do ((i beg (+ i 1)))
         ((= i end))
     (outa i (* (env ampf) (oscil sine-wave (env frqf) )))
     (outb i (* (env ampf) (oscil sine-wave (env frqf) )))
     )))

(with-sound (:srate 48000 :channels 2 :header-type mus-riff  :play #t)
              (myport 0 1 300 300 400 '(0 .3 .5 .1  1 .09) 48000)
              (noport 1.1 .9 400 '(0 .01 1 .1) 48000)

              (myport 2 1 400 400 500 '(0 .2 .5 .1  1 .09) 48000)
              (noport 3.1 .9 500 '(0 .01 1 .1) 48000)

              (noport 4 .3 500 '(0 .19 .3 .001) 48000)
              (myport 4.2 .6 500 500 300 '(0 .001 .5 .1 1 .3) 48000)
              (noport 5 1 300 '(0 .08 .3 .001) 48000)
                )

;portamento adding filters.
(definstrument (myportfilt start-time duration frequency start-freq end-freq (glissamp-env '(0 0 1 1 2 0)) (amp-env '(0 0 1 1 2 1 3 0)) sampling-rate order1 flow1 fhigh1 order2 flow2 fhigh2)
  (let* ((beg (floor (* start-time sampling-rate)))
(end (+ beg (floor (* duration sampling-rate))))
(sine-wave (make-oscil :frequency frequency)) ;sine osc
(ampf (make-env amp-env :duration duration :scaler 1.0)) ;overall amp env
(frqf (make-env '(0 0 1 1) :scaler (hz->radians (- end-freq start-freq)) :duration duration :base 0.67)) ;gliss
(gliss_amp (make-env glissamp-env :duration duration :scaler 1.0)) ;another amp env for the gliss
    (flt1 (make-butterworth-bandpass order1 (hz->radians flow1)  (hz->radians fhigh1)))
    (flt2 (make-butterworth-bandpass order2 (hz->radians flow2)  (hz->radians fhigh2)))
            )
     (do ((i beg (+ i 1)))
         ((= i end))
(outa i (* (env ampf) (+  (* (env gliss_amp)(flt1 (oscil sine-wave  (env frqf)))) (* (env gliss_amp)(flt2 (oscil sine-wave  (env frqf)))))))
(outb i (* (env ampf) (+  (* (env gliss_amp)(flt1 (oscil sine-wave  (env frqf)))) (* (env gliss_amp)(flt2 (oscil sine-wave  (env frqf)))))))
     )))

(with-sound (:srate 48000 :channels 2 :header-type mus-riff  :play #t)
              (noport 0 .55 400 '(0 .03 1 .01) 48000)
              (myportfilt .5 .4 200 200 400 '(0 .3 .4 .1) '(0 0.03 .9 0.06) 48000 8 100 150 8 100 200)
              (noport .5 .5 800 '(0 .01 1 .01) 48000)

             (noport 1 .55 800 '(0 .03 1 .01) 48000)
              (myportfilt 1.5 .4 400 400 200 '(0 .3 .4 .01) '(0 0.03 .9 0.06) 48000 8 100 150 8 100 200)
              (noport 1.5 .5 400 '(0 .01 1 .01) 48000)

              (noport 3 1.1 400 '(0 .03 1 .01) 48000)
              (myportfilt 4 .9 200 200 400 '(0 .3 .9 .1) '(0 0.03 .9 0.06) 48000 8 100 150 8 100 200)
              (noport 5 1 800 '(0 .02 1 .1) 48000)
              )
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