I agree with dbphd. I am going to be adding a pair of F12 Rythmik subwoofers to my system to exactly the same thing. I tried to like the REL subs, but could not hear what a lot of audiophiles claim to be incredible. Since a REL T/9i is rated at 28 Hz at -6 db, I have been told it is lucky to play down to 35 Hz. That is woofer territory. However, perhaps that is why they blend in so much. However, if you can't hear that much of a difference why bother. I don't want to hear a boomy bass sound take over my system. I just want to hear all of the frequencies available on a recording. There is a lot of music recorded that gets down below 24 Hz and I want to hear it. I will try to set up my subs at low volume so they will not stand out and blend with my towers. I talked to Brian at Rythmik and he explained why he came up with his Direct Servo technology. I also talked to a highly respected speaker manufacture and he told me the Rythmik subs are the most musical subs he has ever heard. This is why he builds custom subs using Rythmik drivers and amplifiers. Just hope I will be making the right decision.
Where are the subs?
In listening to the Bach Toccata and Fugue BMV 565, I was struck by how well the organ pedal notes are reproduced since I moved my primary setup to another room. I complemented myself on a fine job of integrating the Velodyne HGS-10 subs with the KEF Ref 1s, using 40 Hz low-pass with 24 dB/octave. But as I thought about it, I didn’t recall connecting the SMS-1 bass manager to the Ayre KX-5 Twenty preamp. I checked. The subs were not connected. The Ref 1s alone where reproducing that satisfying bass. Amazing for stand mounted monitors. I sure as hell didn’t expect that. To confirm, I played the Saint-Seans 3rd Symphony. Same result. Makes me wonder if I need bother connecting the subs.