This should play if your Web browser has WebAssembly enabled (most do). Most examples will play unless they need to load files. The first time you click Play, Csound will spend a few seconds loading, then play. You can edit this code and replay it.
<CsoundSynthesizer> <CsOptions> ; Select audio/midi flags here according to platform ; Audio out Audio in No messages -odac -iadc -d ;;;RT audio I/O ; For Non-realtime ouput leave only the line below: ; -o hilbert_barberpole.wav -W ;;; for file output any platform </CsOptions> <CsInstruments> ; Required settings for WebAudio: sr = 48000 ksmps = 128 nchnls = 2 nchnls_i = 1 ; Initialize the global variables. ; sr = 44100 ; ; kr must equal sr for the barberpole effect to work. kr = 44100 ; ksmps = 1 ; nchnls = 2 ; Instrument #1 instr 1 idur = p3 ibegshift = p4 iendshift = p5 ; sawtooth wave, not bandlimited asaw phasor 100 ; add offset to center phasor amplitude between -.5 and .5 asaw = asaw - .5 ; sawtooth wave, with amplitude of 10000 ain = asaw * 20000 ; The envelope of the frequency shift. kfreq linseg ibegshift, idur, iendshift ; Phase quadrature output derived from input signal. areal, aimag hilbert ain ; The quadrature oscillator. asin oscili 1, kfreq, 1 acos oscili 1, kfreq, 1, .25 ; Based on trignometric identities. amod1 = areal * acos amod2 = aimag * asin ; Calculate the up-shift and down-shift. aupshift = (amod1 + amod2) * 0.7 adownshift = (amod1 - amod2) * 0.7 ; Mix in the original signal to achieve the barberpole effect. amix1 = aupshift + ain amix2 = aupshift + ain ; Make sure the output doesn't get louder than the original signal. aout1 balance amix1, ain aout2 balance amix2, ain outs aout1, aout2 endin </CsInstruments> <CsScore> ; Table 1: A sine wave for the quadrature oscillator. f 1 0 16384 10 1 ; The score. ; p4 = frequency shifter, starting frequency. ; p5 = frequency shifter, ending frequency. i 1 0 6 -10 10 e </CsScore> </CsoundSynthesizer>