highpass takes two or three arguments: a real vector v representing the sampled signal, a real number c specifying the cutoff frequency and optionally a samplerate (which defaults to 44100). This implementation is an emulation of a simple first-order highpass RC filter.

For example, input :

f:=unapply(periodic(sign(x),x,-1/880,1/880),x);

s:=2

playsnd(highpass(s,5000))

s:=2

`^`

14*(apply(f,soundsec(1)));playsnd(highpass(s,5000))