samphold.csd Written by Iain McCurdy 2010 -odac -dm0 sr = 44100 ;SAMPLE RATE ksmps = 32 ;NUMBER OF AUDIO SAMPLES IN EACH CONTROL CYCLE nchnls = 2 ;NUMBER OF CHANNELS (2=STEREO) 0dbfs = 1 ;MAXIMUM AMPLITUDE FLcolor 255, 255, 255, 0, 0, 0 ;SET COLOURS ; LABEL | WIDTH | HEIGHT | X | Y FLpanel "Sample And Hold", 500, 460, 0, 0 ;BORDERS ITYPE, IFONT, ISIZE, IWIDTH, IHEIGHT, IX, IY ih FLbox " ", 6, 9, 15, 490, 95, 5, 255 ;BORDER AROUND ENVELOPE CONTROLS ;SWITCHES ON | OFF | TYPE | WIDTH | HEIGHT | X | Y | OPCODE | INS | STARTTIM | DUR gkOnOff,ihOnOff FLbutton "Note On/Off", 1, 0, 22, 120, 25, 5, 5, 0, 1, 0, -1 gkEnvOnOff,ihEnvOnOff FLbutton "Envelope On/Off", 1, 0, 3, 150, 25, 10, 260, -1 FLsetColor2 255, 255, 50, ihOnOff ;SET SECONDARY COLOUR TO YELLOW ;VALUE DISPLAY BOXES LABEL | WIDTH | HEIGHT | X | Y idSHrate FLvalue " ", 50, 20, 5, 75 idLFOrate FLvalue " ", 50, 20, 5, 125 idLFOrange FLvalue " ", 50, 20, 5, 175 idLFOoffset FLvalue " ", 50, 20, 5, 225 idEnvDur FLvalue " ", 50, 20, 10, 325 ;SLIDERS MIN | MAX | EXP | TYPE | DISP | WIDTH | HEIGHT | X | Y gkgain, ihgain FLslider "Output Gain", 0, 1, 0, 23, -1, 360, 20, 130, 5 gkSHrate, ihSHrate FLslider "Sample and Hold Trigger Rate", 0.1, 50, -1, 23, idSHrate, 490, 25, 5, 50 gkLFOrate, ihLFOrate FLslider "LFO Rate", 0.01, 10, -1, 23, idLFOrate, 490, 25, 5, 100 gkLFOrange, ihLFOrange FLslider "LFO Range", 0.01, 4, 0, 23, idLFOrange, 490, 25, 5, 150 gkLFOoffset, ihLFOoffset FLslider "LFO Offset", 5, 11, 0, 23, idLFOoffset, 490, 25, 5, 200 gkEnvDur, ihEnvDur FLslider "Envelope Duration", 0.05, 3, -1, 23, idEnvDur, 480, 25, 10, 290 FLlabel 13, 1, 1, 255, 255, 255 ;NUMBERS MADE INVISIBLE ; FLBUTBANK TYPE | NUMX | NUMY | WIDTH | HEIGHT | X | Y | IOPCODE | P1 | P2 | P3 gkSourceType, ihSourceType FLbutBank 3, 1, 5, 20, 100, 75, 355, -1 gkSound, ihSound FLbutBank 3, 1, 2, 20, 40, 300, 355, -1 ;GENERAL_TEXT_SETTINGS SIZE | FONT | ALIGN | RED | GREEN | BLUE FLlabel 13, 5, 4, 0, 0, 0 ;LABELS MADE VISIBLE AGAIN ;TEXT BOXES TYPE | FONT | SIZE | WIDTH | HEIGHT | X | Y ih FLbox "LFO Type:", 1, 5, 12, 65, 20, 5, 355 ih FLbox "Sine ", 1, 5, 12, 70, 20, 105, 355 ih FLbox "Triangle", 1, 5, 12, 70, 20, 105, 375 ih FLbox "Saw Down", 1, 5, 12, 70, 20, 105, 395 ih FLbox "Saw Up ", 1, 5, 12, 70, 20, 105, 415 ih FLbox "Noise ", 1, 5, 12, 70, 20, 105, 435 ih FLbox "Sound:", 1, 5, 12, 50, 20, 250, 355 ih FLbox "Simple Sine", 1, 5, 12, 90, 20, 320, 355 ih FLbox "Synth Saw ", 1, 5, 12, 90, 20, 320, 375 ;SET INITIAL VALUES OF FLTK VALUATORS ; VALUE | HANDLE FLsetVal_i 5, ihSHrate FLsetVal_i 0.5, ihLFOrate FLsetVal_i 2, ihLFOrange FLsetVal_i 7, ihLFOoffset FLsetVal_i 0.8, ihEnvDur FLsetVal_i 1, ihEnvOnOff FLsetVal_i 2, ihSourceType FLsetVal_i 0.7, ihgain FLpanel_end ;INSTRUCTIONS AND INFO PANEL FLpanel " ", 512, 520, 510, 0 ;TEXT BOXES TYPE | FONT | SIZE | WIDTH | HEIGHT | X | Y ih FLbox " Sample and Hold (samphold opcode) ", 1, 5, 14, 490, 20, 5, 0 ih FLbox "-------------------------------------------------------------", 1, 5, 14, 490, 20, 5, 20 ih FLbox "Sample and hold is a technique whereby the instantaneous ", 1, 5, 14, 490, 20, 5, 40 ih FLbox "value of a continuously varying signal is held for a defined ", 1, 5, 14, 490, 20, 5, 60 ih FLbox "period of time before the signal is sampled again and the ", 1, 5, 14, 490, 20, 5, 80 ih FLbox "process is repeated. Analog to digital conversion involves ", 1, 5, 14, 490, 20, 5, 100 ih FLbox "the technique of sample and hold but, when used with a much ", 1, 5, 14, 490, 20, 5, 120 ih FLbox "slower rate of resampling, it is also used frequently in ", 1, 5, 14, 490, 20, 5, 140 ih FLbox "synthesis. ", 1, 5, 14, 490, 20, 5, 160 ih FLbox "The 'samphold' opcode take an a or k-rate signal and allows ", 1, 5, 14, 490, 20, 5, 180 ih FLbox "it to pass through unaffected while its gate input is ", 1, 5, 14, 490, 20, 5, 200 ih FLbox "non-zero but holds the instantaneous value whenever its gate ", 1, 5, 14, 490, 20, 5, 220 ih FLbox "input is zero. ", 1, 5, 14, 490, 20, 5, 240 ih FLbox "In this example the frequency of an audio oscillator is ", 1, 5, 14, 490, 20, 5, 260 ih FLbox "modulated by an LFO but the signal from the LFO is first ", 1, 5, 14, 490, 20, 5, 280 ih FLbox "passed through 'samphold'. The user can choose between a ", 1, 5, 14, 490, 20, 5, 300 ih FLbox "a variety of LFO waveform shapes including random. ", 1, 5, 14, 490, 20, 5, 320 ih FLbox "The trigger for the sample and hold gate is a simple ", 1, 5, 14, 490, 20, 5, 340 ih FLbox "metronome (metro opcode). The rate of both the gate trigger ", 1, 5, 14, 490, 20, 5, 360 ih FLbox "and the source LFO can be varied. The relationship between ", 1, 5, 14, 490, 20, 5, 380 ih FLbox "these two should be explored to discover how different ", 1, 5, 14, 490, 20, 5, 400 ih FLbox "motivic patterns can be created. An envelope can be applied ", 1, 5, 14, 490, 20, 5, 420 ih FLbox "to each 'hold' period to further articulate each step. ", 1, 5, 14, 490, 20, 5, 440 ih FLbox "For sonification of the sample and hold data, the user can ", 1, 5, 14, 490, 20, 5, 460 ih FLbox "choose between a simple sine wave oscillator or a more ", 1, 5, 14, 490, 20, 5, 480 ih FLbox "complex lowpass filtered and processed synth sound. ", 1, 5, 14, 490, 20, 5, 500 FLpanel_end FLrun ;RUN THE FLTK WIDGET THREAD gisine ftgen 0,0,65536,10,1 instr 1 ;SAMPLE AND HOLD NOTE SEQUENCER if gkOnOff=0 then ;IF ON/OFF SWITCH IS 'OFF'... turnoff ;TURN OFF THIS INSTRUMENT endif ;END OF CONDITIONAL BRANCH ;MAKE VARIOUS SETTINGS BASED ON LFO TYPE CHOICE if gkSourceType=0 then kLFOtype=0 ;SINE WAVE elseif gkSourceType=1 then kLFOtype=1 ;TRIANGLE elseif gkSourceType=2 then kLFOtype=5 ;SAWTOOTH DOWN (UNIPOLAR) elseif gkSourceType=3 then kLFOtype=4 ;SAWTOOTH UP (UNIPOLAR) endif if gkSourceType=4 then aoct noise gkLFOrange, 0 ;NOISE WAVEFORM else ktrig changed kLFOtype ;GENERATE A 'BANG' TRIGGER (MOMENTARY '1') IF LFO TYPE SELECTION IS CHANGED if ktrig=1 then ;IF 'BANG' IS RECEIVED... reinit RESTART_LFO ;BEGIN A REINITIALISATION PASS BEGINNING FROM LABEL 'RESTART_LFO' endif ;END OF CONDITIONAL BRANCH RESTART_LFO: ;LABEL aoct lfo gkLFOrange, gkLFOrate, i(kLFOtype) ;LFO GENERATES FREQUENCY VALUES FOR OSCILLATOR rireturn ;RETURN FROM REINITIALISATION PASS if gkSourceType=2||gkSourceType=3 then ;SAWTOOTH WAVEFORMS WITH lfo OPCODE ARE UNIPOLAR. WE WILL RE-RANGE LFO OUTPUT SO THAT IT IS BI-POLAR IF EITHER OF THESE TYPES HAS BEEN SELECTED aoct = (aoct * 2) - gkLFOrange ;RE-RANGE LFO endif ;END OF CONDITIONAL BRANCH endif ;END OF CONDITIONAL BRANCH kgate metro gkSHrate ;TRAIN OF GATE TRIGGERS TO BE USED BY SAMPLE AND HOLD MECHANISM if gkEnvOnOff=1 then ;IF 'ENVELOPE' OPTION HAS BEEN SELECTED... ;ALSO RESTART A PERCUSSIVE ENVELOPE WHENEVER A GATE TRIGGER IS RECEIVED TO ARTICULATE CHANGES IN PITCH IN THE OSCILLATOR if kgate=1 then ;IF TRIGGER IS RECEIVED (I.E. = 1)... reinit RESTART_ENVELOPE ;RE-INITIALISE FROM LABEL 'RESTART_ENVELOPE' endif ;END OF CONDITIONAL BRANCH RESTART_ENVELOPE: ;A LABEL aenv expseg 0.001,0.01,1,i(gkEnvDur),0.0001 ;PERCUSSIVE TYPE AMPLITUDE ENVELOPE rireturn ;RETURN FROM RE-INITIALISATION PASS TO NORMAL PERFORMANCE PASSES aenv tone aenv, 500 ;SMOOTH AMPLITUDE ENVELOPE A LITTLE (TO REMOVE CLICKS WHENEVER AN ENVELOPE IS INTERRUPTED BY A RE-INITIALISATION) else ;OTHERWISE... aenv = 1 ;AMPLITUDE IS A CONSTANT (NO ENVELOPE) endif ;END OF CONDITIONAL BRANCH aoct samphold aoct + gkLFOoffset, kgate ;APPLY SAMPLE-AND-HOLD TO THE LFO GENERATED FREQUENCY VALUES (AND ADD AN OFFSET) ;---------------------------------------------------------------------------------------------------------------------------------- ; A SIMPLE SINE WAVE SONIFICATION ;---------------------------------------------------------------------------------------------------------------------------------- if gkSound==0 then asig poscil 0.7*aenv*gkgain, cpsoct(aoct), gisine ;AUDIO OSCILLATOR outs asig,asig ;SEND AUDIO TO OUTPUTS ;---------------------------------------------------------------------------------------------------------------------------------- ; A MORE COMPLEX SYNTH SONIFICATION ;---------------------------------------------------------------------------------------------------------------------------------- else koct downsamp aoct ;NEED TO DOWNSAMPLE TO K-RATE FOR vco2 asig vco2 0.4*gkgain, cpsoct(koct) ;CREATE A VCO SAWTOOTH OSCILLATOR kcfbas rspline 7,12,0.05,0.2 ;FILTER FREQ. BASE VALUE kenvdep rspline 0,2,0.1,0.5 ;FILTER FREQ. ENVELOPE DEPTH kcfenv loopseg gkSHrate, 0, 0, kenvdep , 1, 0 ;FILTER FREQ. ENVELOPE kres rspline 0.4,0.85,0.05,0.2 ;FILTER RESONANCE kdist rspline 0,10,0.1,0.2 ;FILTER DISTORTION afilt lpf18 asig,cpsoct(kcfenv+kcfbas),kres,kdist ;FILTER THE SAWTOOTH AUDIO asig balance afilt,asig ;BALANCE THE SIGNAL TO PREVENT LARGE VARIATIONS IN AMPLITUDE WHEN DISTORTION OR RESONANCE ARE HIGH asig = asig* aenv ;APPLY THE AMPLITUDE ENVELOPE atimL rspline 10,100,0.01,0.1 ;LEFT CHANNEL DELAY TIME atimR rspline 10,100,0.01,0.1 ;RIGHT CHANNEL DELAY TIME aL vdelay asig,atimL,1000 ;CREATE LEFT CHANNEL DELAY aR vdelay asig,atimR,1000 ;CREATE RIGHT CHANNEL DELAY kRvTim rspline 0.5,0.9,0.05,0.2 ;REVERB TIME kRvMix rspline 0,1,0.03,0.09 ;REVERB MIX aRvL,aRvR reverbsc aL,aR,0.5,8000 ;STEREO REVERB SIGNAL CREATED outs aL+aRvL*kRvMix,aR+aRvR*kRvMix ;SEND AUDIO TO OUPUT endif endin f 0 3600 ;DUMMY SCORE EVENT - KEEPS PERFORMANCE GOING FOR 1 HOUR