Hi
There are several possible ways, but are a bit phaffy.
One simple way is as follows....
Load the clip/movie to the media list and then place it on the sequence line.
Switch into timeline mode.
Left click the sound track without unlinking it and then playing the soundtrack in the left hand preview pane. (you can drag the red line along if required)
Stop at the point the offending sound starts and then left click the yellow sound level line at the point where the red cursor line intersects it.
This will place a red dot at this point and fix the volume line.
Grab the yellow line just to the right of this point and then drag it down to the bottom of the window directly under the red dot. (Dont go past it to the left or the line will jump down from the start of the clip)
Aim to get the yellow line to drop straight down to the bottom of the screen under the first red dot.
When you release it there will be a second fixed point.
Now grab the yellow line to the right of the second marker and drag it back up to the cenre line again.
This fixes the level.with another third red dot.
The sound level line will now be slanting upwards from the second dot to the third dot.
Now grab the slanting sound lineto the left of the third dot and drag it along vertically below the third dot
What you should have now is a yellow line (sound level) that drops to the bottom of the screen at the start of your offending sound, runs along horizontally until the end of the offending sound and then rises straight up again to the original level. In effect reducing the volume for the extent of the unwanted sound.
You can easily adjust the volume line by dragging the red dots until the effect you want is obtained.
In some cases this may not entirely mute the sound however.........
Another way risks de-synching the sound if you are not careful but is possible to completely mute small sections of the soundtrack as follows:-
Put the clip/film on the sequence lineand switch to timeline mode
Unlink the sound track. (but dont move it). It will drop to a lower track.
Enlarge the sequence line (+soundtrack) using the + button at the bottom right, until all the sound peaks are easily visible.
Play the film and stop the red cursor where the offending sound is about to start. (you can drag the cursor L/R and pinpoint the sound peak.)
Now split the soundtrack at that point.
Play to the end of the offending sound and in the same way split the soundtrack again.
Right click the sound section you have isolated and either..
1) Delete it
2) Adjust the clip volume and mute it.
If you have a bleep soundbite, you could add it to the space or to a separate track.
You will need to be careful to check the soundtrack does not move once it is unlinked.
Hope this helps
Nat