JCHOR

Granulated chorus instrument.

in RTcmix/insts/jg

quick syntax:

JCHOR(outsk, insk, dur, indur, inmaintain, pitch, nvoices, MINAMP, MAXAMP, MINWAIT, MAXWAIT, seed, inputchan, AMPENV, GRAINENV)

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.

Param Field Parameter Units Dynamic Optional Notes
p0 output start time seconds no no  
p1 input start time seconds no no  
p2 output duration seconds no no  
p3 input duration seconds, not input end time no no  
p4 maintain input duration, regardless of transposition 1: yes, 0: no no no  
p5 transposition oct.pc no no  
p6 number of voices - no no minimum of 1
p7 minimum grain amplitude relative multiplier of p13 yes no  
p8 maximum grain amplitude relative multiplier of p13 yes no  
p9 minimum grain wait seconds yes no  
p10 maximum grain wait seconds yes no  
p11 seed 0-1 no no  
p12 input channel - no no  
p13 overall amplitude relative multiplier of input sound yes no  
p14 grain envelope reference to a pfield table-handle no no  

Parameters labled as Dynamic can receive dynamic updates from a table or real-time control source.

Author: John Gibson, 9/20/98, RT’d 6/24/99; rev for v4, 7/24/04 based on Paul Lansky’s CMIX chor instrument and Doug Scott’s TRANS code

JCHOR is a random-wait chorus instrument based on Paul Lansky’s old CMIX chor instrument and Doug Scott’s TRANS. Essentially this is a granular synthesis instrument optimized to produce ‘choir-like’ sounds. Paul Lansky used this approach in man of his Idle Chatter pieces (the chords in the background).

Usage Notes

Because the transposition method doesn’t try to maintain duration – it works like the speed control on a tape deck – you have an option about the way to handle the duration of the input read:

JCHOR places no limit on input duration or number of voices. It does transpose the input signal according to the oct.pc value given in p5 (“pitch”).

p14 (“GRAINENV”) is a pfield-handle reference to a table with the envelope to be applied for each grain. NOTE: You will probably need to set the reset control-rate value (see the reset scorefile command) fairly high for small grains.

Output can be either mono or stereo. If it’s stereo, the program randomly distributes the voices across the stereo field.

Sample Scores

very basic:

   rtsetparams(44100, 2)
   load("JCHOR")
   
   rtinput("mysound.aif")
   inchan = 0
   inskip = 0.20
   
   outdur = 10
   
   indur = 0.60
   maintain_dur = 1
   transposition = 0.07
   nvoices = 50
   minamp = 0.01
   maxamp = 1.0
   minwait = 0.00
   maxwait = 0.30
   seed = 0.9371
   
   amp = 0.5
   env = maketable("line", 1000, 0,0, 1,1, outdur-1,1, outdur,0)
   
   grainenv = maketable("window", 1000, "hanning")
   
   JCHOR(0, inskip, outdur, indur, maintain_dur, transposition, nvoices,
      minamp, maxamp, minwait, maxwait, seed, inchan, amp * env, grainenv)

slightly more advanced:

   rtsetparams(44100, 2)
   load("JCHOR")
   
   rtinput("mysound.wav")
   inchan = 0
   
   outdur = 16
   inskip = 0.01
   indur = 0.20
   maintain_dur = 1
   transposition = 0.02
   nvoices = 60
   minamp = 0.1
   maxamp = 1.0
   minwait = 0.00
   maxwait = 0.60
   seed = 0.9371
   
   amp = 6.0
   env = maketable("line", 1000, 0,0, 1,1, outdur-3,1, outdur,0)
   
   grainenv = maketable("window", 1000, "hanning")
   
   reset(2000)
   
   outskip = 0
   JCHOR(outskip, inskip, outdur, indur, maintain_dur, transposition, nvoices,
      minamp, maxamp, minwait, maxwait, seed, inchan, amp * env, grainenv)
   
   outskip = 2
   outdur -= outskip
   amp = 0.6
   indur = 0.90
   transposition = -0.10
   maxamp = 0.5
   maxwait = 1.0
   seed = 0.2353
   JCHOR(outskip, inskip, outdur, indur, maintain_dur, transposition, nvoices,
      minamp, maxamp, minwait, maxwait, seed, inchan, amp * env, grainenv)

See Also

GRANSYNTH, GRANULATE, JGRAN, SGRANR, STGRANR