an open-source digital signal processing and sound synthesis language
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MULTICOMB -- multiple comb filters
in RTcmix/insts/std


quick syntax:
MULTICOMB(outsk, insk, dur, AMP, combfreqlo (Hz), combfreqhi (Hz), REVERBTIME[, inputchan, ringdowndur])

CAPITALIZED parameters are pfield-enabled for table or dynamic control (see the maketable or makeconnection scorefile commands). Parameters after the [bracket] are optional and default to 0 unless otherwise noted.



   p0 = output start time (seconds)
   p1 = input start time (seconds)
   p2 = input duration (seconds)
   p3 = amplitude multiplier (relative multiplier of input signal)
   p4 = comb frequency range bottom (Hz)
   p5 = comb frequency range top (Hz)
   p6 = reverb time (seconds)
   p7 = input channel [optional; default is 0]
   p8 = ring-down duration [optional; default is reverb time (p6)]

   p3 (amplitude) and p8 (reverb time) can receive dynamic updates from a
   table or real-time control source.

   Author:  Brad Garton; rev. for v4.0 by JGG, 7/10/0



MULTICOMB process an input signal using four simultaneous comb filters randomly chosen within a specified range (and spread across the stereo field)

Usage Notes

You can't specify the actual comb filter frequencies chosen directly, but it's still fun to use. Narrow ranges will converge on a particular pitch if you'd like.

The optional ring-down duration parameter (p8) is to let you control how long the combs will ring after the input has stopped. If the reverb time is constant, MULTICOMB will figure out the correct ring-down duration for you. If the reverb time is dynamic, you need to specify a ring-down duration if you want to ensure that your sound will not be cut off prematurely.

The output of MULTICOMB is stereo.

Sample Scores

very basic:
   rtsetparams(44100, 2)
   load("MULTICOMB")

   rtinput("mysound.aif")

   ampenv =  maketable("line", 1000, 0,0, 0.5,1, 4.0,1, 4.3,0)

   MULTICOMB(0, 0, 4.3, 0.1*ampenv, cpspch(6.02), cpspch(9.05), 1)


slightly more advanced:
   set_option("full_duplex_on")
   rtsetparams(44100, 2, 256)
   load("MULTICOMB")

   rtinput("AUDIO")
   reset(20000)

   srand(87)

   ampenv = maketable("line", 1000, 0,0, 1,1, 3,1, 5,0)

   for(start = 0; start < 30; start = start + 2.5) {
      low = random() * 500.0 + 50.0
      hi = low + (random() * 300.0)
      MULTICOMB(start, 0, 5, 0.04, low, hi, 2.5)
   }


See Also

maketable, COMBIT, DELAY, FLANGE, IIR, JDELAY, REV, REVERBIT, REVERBIT