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 biquad.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 = 4410 ; ksmps = 10 ; nchnls = 2 ; Instrument #1. instr 1 ; Get the values from the score. idur = p3 iamp = p4 icps = cpspch(p5) kfco = p6 krez = p7 ; Calculate the biquadratic filter's coefficients kfcon = 2*3.14159265*kfco/sr kalpha = 1-2*krez*cos(kfcon)*cos(kfcon)+krez*krez*cos(2*kfcon) kbeta = krez*krez*sin(2*kfcon)-2*krez*cos(kfcon)*sin(kfcon) kgama = 1+cos(kfcon) km1 = kalpha*kgama+kbeta*sin(kfcon) km2 = kalpha*kgama-kbeta*sin(kfcon) kden = sqrt(km1*km1+km2*km2) kb0 = 1.5*(kalpha*kalpha+kbeta*kbeta)/kden kb1 = kb0 kb2 = 0 ka0 = 1 ka1 = -2*krez*cos(kfcon) ka2 = krez*krez ; Generate an input signal. axn vco 1, icps, 1 ; Filter the input signal. ayn biquad axn, kb0, kb1, kb2, ka0, ka1, ka2 outs ayn*iamp/2, ayn*iamp/2 endin </CsInstruments> <CsScore> ; Table #1, a sine wave. f 1 0 16384 10 1 ; Sta Dur Amp Pitch Fco Rez i 1 0.0 1.0 20000 6.00 1000 .8 i 1 1.0 1.0 20000 6.03 2000 .95 e </CsScore> </CsoundSynthesizer>