In my videos, I am using Low-Cut (High-Pass) filter coming with Tascam DR-07X to eliminate ambient sound such as air conditioning or computer fan noise, etc. but they seem only to be eliminated during my silence, but when I start talking, the background noises get picked up again. Currently, the low-cut Hz is set to 40.
Here is the video where you can clearly see the problem I am talking about:
What do you guys think the problem is, and how can I fix (preferably w/o any software help).