Thought I would post my experience with building the Rythmik 15 in servo sub. My requirements were for a sub to be used for 50% music and 50% home theater in a 2800 cu ft room. This is my first sub as I have always had full range speakers at least down to 40 hz but wanted to see what a good sub would do for lowest frequencies. I choose the 15 in with the Rythmik PEQ servo amp. Built the enclosure as a sealed 3.2 cuft. out of 0.75 MDF. First I was concerned if and how the sub would integrate with my Zaph TMM waveguide main speakers, they work very well together. I crossover the sub at 40hz and ran the Zaph full range. The sub has added a sonic dimension that I didn't know I was missing It works very well for music only making itself known when the frequencies are there and enhances the home theater experience as I only run mains with and the sub. Highly recommended for a quality sub with minimal effort.