### 5.25.4 Low-pass filtering : lowpass

lowpass takes two or three arguments: an audio clip or a real vector v representing the sampled signal, a real number c specifying the cutoff frequency and optionally a samplerate (which defaults to 44100). The command returns the input data after applying a simple first-order lowpass RC filter.

For example, input :

f:=unapply(periodic(sign(x),x,-1/880,1/880),x);
s:=apply(f,soundsec(3)):;
playsnd(lowpass(createwav(s),1000))