class:: HPF
summary:: 2nd order Butterworth highpass filter.
related:: Classes/BPF, Classes/BRF, Classes/LPF
categories::  UGens>Filters>Linear


Description::
A second order high pass filter.


classmethods::

method::ar, kr

argument::in

The input signal.


argument::freq

Cutoff frequency in Hertz.
WARNING: due to the nature of its implementation frequency values close to 0 may cause glitches and/or extremely loud audio artifacts!


argument::mul

Output will be multiplied by this value.


argument::add

This value will be added to the output.


Examples::

code::
{ HPF.ar(Saw.ar(200, 0.1), FSinOsc.kr(XLine.kr(0.7, 300, 20), 0, 3600, 4000), 5) }.play;

(
{ 	var ctl = HPF.kr(LFSaw.kr(5), SinOsc.kr(XLine.kr(0.07, 30, 20), 0, 35, 40)) ;
	SinOsc.ar(ctl * 200 + 500);
}.play;
)

(
{ 	var ctl = HPF.kr(LFSaw.kr(5, 0.1), MouseX.kr(2, 200, 1));
	SinOsc.ar(ctl * 200 + 400) * 0.1;
}.play;
)
::