subwoofer suggestions

Looking for sub with balance between tuneful bass for music and deep bass for movies to be 0.1 part of Monitor Audio Apex 5.1 speaker system. Front speakers go down into low 50Hz while rears go down to mid 60s. Room is 8' high x 18' wide x 12' deep, is reasonably well treated, but size will limit the longest waves. While there is no point in overloading room with a giant box and driver, pressure and speed with good tone are all desirable assets. Upper budget is about $1500, but I will consider more budget conscious options.

Thanks in advance for your suggestions,

kn