scanu — Compute the waveform and the wavetable for use in scanned synthesis.
Plugin opcode in scansyn.
Compute the waveform and the wavetable for use in scanned synthesis.
scanu init, irate, ifndisplace,
ifnmass, ifnmatrix, ifncentr, ifndamp, kmass, kmtrxstiff, kcentr,
kdamp, ileft, iright, kpos, kdisplace, ain, idisp, id
init -- the initial position of the masses. If this is a negative number, then the absolute of init signifies the table to use as a hammer shape. If init > 0, the length of it should be the same as the intended mass number, otherwise it can be anything.
irate -- the amount of time between successive updates of the mass state. Kind of like the sample period of the system. If the number is big, the string will update at a slow rate showing little timbral variability; otherwise it will change rapidly resulting in a more dynamic sound.
ifndisplace -- the ftable that contains the initial velocity for each mass. It should have the same size as the intended mass number.
ifnmass -- ftable that contains the mass of each mass. It should have the same size as the intended mass number.
ifnmatrix -- ftable that contains the spring stiffness of each connection. It should have the same size as the square of the intended mass number. The data ordering is a row after row dump of the connection matrix of the system.
ifncentr -- ftable that contains the centering force of each mass. It should have the same size as the intended mass number.
ifndamp -- the ftable that contains the damping factor of each mass. It should have the same size as the intended mass number.
ileft -- If init < 0, the position of the left hammer (ileft = 0 is hit at leftmost, ileft = 1 is hit at rightmost).
iright -- If init < 0, the position of the right hammer (iright = 0 is hit at leftmost, iright = 1 is hit at rightmost).
idisp -- If 0, no display of the masses is provided.
id -- If positive, the ID of the opcode. This will be used to point the scanning opcode to the proper waveform maker. If this value is negative, the absolute of this value is the wavetable on which to write the waveshape. That wavetable can be used later from an other opcode to generate sound. The initial contents of this table will be destroyed.
kmass -- scales the masses
kmtrxstiff -- scales the spring stiffness.
kcentr -- scales the centering force
kdamp -- scales the damping
kpos -- position of an active hammer along the string (kpos = 0 is leftmost, kpos = 1 is rightmost). The shape of the hammer is determined by init and the power it pushes with is kstrngth.
kdisplace -- power that the active hammer uses.
ain -- audio input that adds to the velocity of the masses. Amplitude should not be too great.
The scanu matrix format is a binary list of connections. There is no weight given to the link; it is assumed to be unity.
For example, a circular string of 4 would be coded as
0
1
0
0
1
0
1
0
0
1
0
1
0
0
1
0
Note: to avoid confusion with other matrix formats, it is best to save this matrix format file using the extension file.matrxB.
Here is an example of the scanu opcode. It uses the files scanu-musical.csd and MIDIpad.mid.
Example 927. Example of the scanu opcode.
See the sections Real-time Audio and Command Line Flags for more information on using command line flags.
<CsoundSynthesizer> <CsOptions> -odac -d -F "MIDIpad.mid" ; For Non-realtime ouput leave only the line below: ; -o scanu-musical.wav -W ;;; for file output any platform </CsOptions> <CsInstruments> ; by Shengzheng Zhang (aka John Towse) sr = 44100 ksmps = 32 nchnls = 2 0dbfs = 1 itmp ftgen 1, 0, 128, 7, 0, 64, 1,64, 0 ; generating all bunch of tables needed itmp ftgen 2, 0, 128, -7, 1, 128, 1 itmp ftgen 3, 0, 16384, -23, "string-128.matrxB" itmp ftgen 4, 0, 128,-7 ,0.5 ,128, 0 itmp ftgen 5, 0, 128, -7, 1, 128, 1 itmp ftgen 6, 0, 128, -7, 0, 128, 0 itmp ftgen 7, 0, 128, -7, .001, 128,128 gal init 0 ; getting reverb and delay ready gar init 0 gavl init 0 gavr init 0 instr 1 kpan randh 1, 3 ; random panning kpan port kpan, 0.05 ;make the panning change not so quick kpitch cpsmidib 12 ipitch cpsmidi kenvm madsr 0.02, 0.6, 0.2, 1 kenv2 madsr 0.1, 0.6, 0.8, 1 kenv3 madsr 0.8, 0.6, 0.8, 1 kvib lfo 1, 5 ifnvel = 1 ifnmass = 2 ifnstif = 3 ifncentr = 4 ifndamp = 5 kstif = 0.3 + 0.1*kvib * kenv3 kmass = 10-(5*kenvm) ; modulated mass kcentr = 0.1 kdamp = -0.02 ileft = 0.2 iright = 0.8 kpos = 0.2 kstrngth = 0.005 ;setups for scan synthesis a2 madsr 0.002, 0.01, 0.001, 0 ;get a initial pick, but seemed like not working scanu 1, 0.1,ifnvel, ifnmass,ifnstif,ifncentr, ifndamp,kmass, kstif, kcentr, kdamp, ileft, iright,kpos,kstrngth, a2*0.5, 0.2, 1 a1 scans .01*kenv2, kpitch+kpitch*kvib*kenv3*0.01, 7, 1 a1 dcblock a1 a1 butterlp a1, kpitch*8 a1 butterlp a1, kpitch*12 al = a1*kpan ar = a1*(1-kpan) outs al, ar vincr gal, al vincr gar, ar vincr gavl, al vincr gavr, ar endin instr 2 abuf delayr 5 adl deltap 0.3 delayw gal + (adl * 0.2) abuf delayr 5 adr deltap 0.4 delayw gal + (adr * 0.2) outs adl, adr clear gal clear gar endin instr 3 adl, adr reverbsc gavl, gavr, 0.85, 12000 outs adl, adr clear gavl clear gavr endin </CsInstruments> <CsScore> i2 0 70 i3 0 70 e </CsScore> </CsoundSynthesizer>
More information on this opcode: http://www.csounds.com/stevenyi/scanned/yi_scannedSynthesis.html , written by Steven Yi