My 25year old M&K no longer seemed to do the job. I decided to try a 700w which was on sale at BestBuy. I was looking at other subs but was not interested in a boomy sound like was I found in a few brands. Although the 700w was not as costly as M&K's would be I bought it now, the 700w was worth a try. My center and rear speakers are Martin Logan so as they matched well with my KEFs I thought I would try it. My great room is 20x18 sound it is not a large room. WOW I was really suprised at the depth and tight bass that it supplied. I used the LFE input from my MAC and it just made the bass come alive on one of my favorite movies Stargate. As with my other movies it did it bass job as I feel it should have. Coming in seamlessly and not standing out as a over bassed. I like the opening of Stargate and was missing the Pyramid craft landing bass with my old M&Ks. Worth very penny! I also belive the technology has improved since my M&Ks were new. Just loving the sound.