Sound deadening material outside speakers

[porthole]

I am thinking of trying to minimize the "sound intrusion" into the bedroom from the external speakers.
You can see behind the dresser drawers that the outside speakers are exposed.

My idea is to somehow seal up that area, maybe with an acoustical mat or similar.

Then hopefully with minimal exterior speaker noise in the bedroom adding a speaker switch and some type of speakers for the bedroom.

Any ideas of a way to block the sound from outside?

 

[rl7greg]

I would put some mat like this - http://www.dynamat.com/products_car_audio_speaker_kit.html - behind the whole speaker so it seals on all sides. Would probably work... Maybe put a circle of wax paper in the middle so it doesn't stick to the speaker itself - it is sticky stuff.