Rym, I'm trying to edit a audio clip for project at work and trying to remove the background noise and hissing sound in the clip. I'm pretty sure that I want to be using a noise gate filter, but I'm not sure where to start in tuining it to get it to work correctly. It gives me 4 options, Threshold, ratio, attack time and release time. I thought Threshold would be where I want to start working, but if I change it, I can't observe any effects in the clip.