I had a similar need for a system I have at a second home. In the middle of looking and considering several options I can across SOUNDMATTERS. They have a sub product that is small, flat and with the optional mounting kit can be wall mounted and out of the way. A wall mounted sub? That can't be any good I thought. Well, I wanted to know and ordered one which arrived in 3 days and it took seconds to set-up and adjust. I have to say I was surprised by the sound quality I heard from this sub out of the box and it has only gotten better. At $300 I never thought it would sound that good. I am happy with it in my system.