Lag3UD is equivalent to LagUD.kr(LagUD.kr(LagUD.kr(in, timeU, timeD), timeU, timeD), timeU, timeD), thus resulting in a smoother transition. This saves on CPU as you only have to calculate the decay factor once instead of three times. See LagUD for more details.
| in | input signal. | 
| lagTimeU | 60 dB lag time in seconds for the upgoing signal. | 
| lagTimeD | 60 dB lag time in seconds for the downgoing signal. |