# How can i silence this?

I need to silence (extactly at zero!) the central “noise” of this -sound-.
This “noise to silence” is present in other places in the audio track…
How can i do this (automagically) with Nyquist?

I’m not sure exactly what you are wanting to do, but I’m guessing that a “noise gate” is the effect you are looking for: http://wiki.audacityteam.org/wiki/Nyquist_Effect_Plug-ins#Noise_Gate

Ok…
I have already made some attempts … but i could not do anything useful…
Is possible to use GATE or NOISE-GATE inside a Nyquist “script”?
Can you explain me how to do it…?
I still have only errors…

``````(noise-gate (highpass8 *track* 3000))
``````

gives me

``````break: lookahead must be greater than risetime in GATE function
if continued: return from BREAK
Function: #<Subr-BREAK: #4a44198>
Arguments:
"lookahead must be greater than risetime in GATE function"
Function: #<FSubr-COND: #4a42a40>
Arguments:
((< LOOKAHEAD RISETIME) (BREAK "lookahead must be greater than risetime in GATE function"))
((OR (< RISETIME 0) (< FALLTIME 0) (< FLOOR 0)) (BREAK "risetime, falltime, and floor must all be positive in GATE function"))
(T (LET ((S (SND-GATE (SEQ (CUE SOUND) (ABS-ENV (S-REST LOOKAHEAD))) LOOKAHEAD RISETIME FALLTIME FLOOR THRESHOLD))) (SND-XFORM S (SND-SRATE S) (SND-T0 SOUND) (+ (SND-T0 SOUND) LOOKAHEAD) MAX-STOP-TIME 1)))
Function: #<Closure-GATE: #2e844c8>
Arguments:
#<Sound: #2d3d698>
0.01
0.02
0.5
0.5
0.0001
Function: #<FSubr-LET: #4a3e328>
Arguments:
((RMS (LP (MULT SND SND) (/ *CONTROL-SRATE* 10))))
(SETF THRESHOLD (* THRESHOLD THRESHOLD))
(MULT SND (GATE RMS FLOOR RISETIME FALLTIME LOOKAHEAD THRESHOLD))
Function: #<Closure-NOISE-GATE: #2e36bf8>
Arguments:
#<Sound: #2d3d788>
1>
``````

I found this in manual

(noise-gate sound [lookahead risetime falltime floor threshold]) [LISP]
A simple noise gate implementation based on gate. All parameters except snd are optional and default values are lookahead: 0.5, risetime: 0.02, falltime: 0.5, floor: 0.01, threshold: 0.01. The result is the input snd, where below-threshold segments of sound are silenced.

Crossed posts. Please see my previous reply. If you want to make your own “gate”, the Noise Gate in the link may be instructive.