BEST SUB FOR HT:MUSIC 50-50 with CM9/CMC2/CM5

Do you have a budget?

SVS make awesome subs, even the drivers are built in house.

I have the same speakers I have a Martin Logan depth i. But I will be trying the supercube 4000 in a week. I will tell you the winner after I try both.

Without a budget and the word, "best," in your question these AGone links should provide a quick variety of size, price, and features, that may suit your needs. Happy shopping.

http://app.audiogon.com/listings?search_text=velodyne%20&page=1&no_listing_types_auctions=false&no_listing_types_classifieds=false&items_per_page=50&location_filter_radius=25&filter_category_id%5B%5D=30&min_condition=1&max_condition=11&listing_types_auctions=1&listing_types_classifieds=1

http://app.audiogon.com/listings?search_text=JL%20audio&page=1&no_listing_types_auctions=false&no_listing_types_classifieds=false&items_per_page=50&location_filter_radius=25&filter_category_id

Do not only consider the size of the subwoofer. You should consider the power, sensitivity rating, and enclosure type. If you would like the system to play loud, low music, and you also have enough space, then choose the biggest subwoofer possible. Do not underestimate the small subwoofer. I am also using  some models at my Karate uniform store.