Merlin VSM

Any of the Merlin VSMs will provide a heckuva lot more bass extension than your Kef monitors - whether that's enough to satisfy you, who knows?. IME, the VSMs will be -3 db somewhere around 35hz in most rooms of your size. The more recent versions of this speaker tend to be voiced a bit fuller through the mid/upper bass than earlier versions.

Hifiman's suggestion of subs and sats may provide more "thump" down low - which may prove satisfying on rock music, in particular. If you opt for multiple subs and/or EQ, you'll also probably be able to get flatter in-room response below 100hz than you can with the Merlins. But the VSMs certainly have their own charms - great speakers.

good luck

Marty

I have my Merlins in the same size room. I have tried many speakers and for my taste they are among the best speakers made, period. I listen mainly to jazz and acoustic folk/rock and the bass seems plenty deep for me. For full Symphonic they can't recreate the sense of scale of a symphonic hall, pretty tough to do without some large bass drivers to create that subsonic energy - but for most applications, I think you cannot go wrong with Merlins, especially if you use tube amps.

teeshot, in a 13 by 20 foot room with your amp you would have powerful and deep bass imho. i have used them at shows in up to 4400 cu ft volume with great results. i personally like the sound of the primare very much so no problems there. a vsm mxe or mme would be a better choice because they are lead free and do sound fuller and more room filling. i agree with what hifiman said in part but the sbam that comes with the vsm does a very similar thing by filtering out of band energy below the resonant frequency of the woofer. this reduces 2nd and 3rd order harmonic distortion in the bass. this can be decribed as the typical booming one hears in the bottom end of virtually all speakers unless they are protected in this manner.
what kind of cables are you planning on using? are the speaker wires single run or bi-wire?
best, b

Teeshot,

I am in a room the same size and with the VSM MXe driven with 100 watt OTL amps I get bass that is powerful, deep with excellent pitch, definition and articulation. The latest MXe lead free is fuller and more relaxed sound top to bottom as well. There is a clarity to the speaker that must be heard to believe. Careful set up of upstream components, wires and power rewards you with a great musical experience.

The customer service from Bobby and his team is hard to beat as well. They are dedicated to you getting the most out of the speakers and willing to go the extra mile.

Bobby can't resist the urge to grandstand.

Astute readers will note his previous post was removed due to the outrageous level of self promotion and blatant advertising content.

Again.