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


Description::

A second order low 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::
{ LPF.ar(Saw.ar(200,0.1), SinOsc.kr(XLine.kr(0.7,300,20),0,3600,4000)) }.play;

// kr:
(
{ var ctl = LPF.kr(LFPulse.kr(8), SinOsc.kr(XLine.kr(1, 30, 5)) + 2);
	SinOsc.ar(ctl * 200 + 400)
}.play;
)

(
{ var ctl = LPF.kr(LFPulse.kr(8), MouseX.kr(2, 50, 1));
	SinOsc.ar(ctl * 200 + 400)
}.play;
)
::