class:: Lag2UD
summary:: Exponential lag
categories:: UGens>Filters
related:: Classes/Lag, Classes/Lag2, Classes/Lag3, Classes/LagUD, Classes/Lag3UD

description::
Lag2 is equivalent to Lag.kr(Lag.kr(in, time), time), thus resulting in a smoother transition. This saves on CPU as you only have to calculate the decay factor once instead of twice. See link::Classes/Lag:: for more details.

classmethods::
method:: ar, kr

argument:: in
input signal.
argument:: lagTimeU
60 dB lag time in seconds for the upgoing signal.
argument:: lagTimeD
60 dB lag time in seconds for the downgoing signal.

examples::
code::
(
// used to lag pitch
       SynthDef( \lag2ud_help,

	{ arg freq=300,lagup=1, lagdown=5;
		Out.ar( 0,
			SinOsc.ar( // sine wave
				Lag2UD.kr( // lag the frequency
					freq,
					lagup,
					lagdown
				),
				0, // phase
				0.2 // sine amplitude
			)
		);
	}).add;
)

x = Synth.new( \lag2ud_help ); // create the synth

x.set( \freq, 500 ); // set the frequency to a higher value (takes 1 second)
x.set( \freq, 100 ); // set the frequency to a lower value (takes 5 seconds)
x.free;
::