Help wanted: Bass!

I’m in need of augmenting the bass in my system. I’m the old school type and would rather NOT go the sub route.

My system and environment:
• Pre:   Conrad Johnson Premier 16LS
• Pwr:   Conrad Johnson Premier 12 Mono Blocks
• Pwr Condtnr: Shunyata Hydra
• Speakers: Tannoy Kensingtons
• Cabeling: Stealth PGS IC’s, Vandenhull Bi-wire Speaker wiring
• Sources: Conrad Johnson DV-2B CD Player, SOTA Star w/SME arm w/Grado cart, Magnum Dynalab Tube Tun 
• Music:   Classic Rock, Easy listening, Female Jazz singers, Classical
• Room:   Big (25 X 30) w/cathedral ceiling. Harwood floors/ceiling and big glass windows. Rugs and furniture

Came across the Emerald Physics Bass Manager claims to add 1/2 octave of bass to any speaker. IYO, could that be a solution? Are there similar helpers like this out there? Not much in the budget (about $500) for a near-term purchase. Could double that for a longer-term.

Again, not wanting to go the sub route unless I have too. Can’t do room treatments or alter room configuration (it’s our living room) either.

Any thoughts/suggestions will be greatly appreciated – thank you!

I am glas I use SS, I am OCD enough without having to try a gaggle of tubes
To atmasphere above: viola!  Of course!  And I know better!  Pre amps tend to require speaker lead inversion.  My First Sound PD III and Cary SLP98 before it both do. While swapping out amps and speakers it's easy to forget that.  You just helped me immensely, thank you.  Personally I've had several subs and for strictly two channel I've sold every one of them, or pairs.  Could never get them to disappear.  Overstated bass drew unwanted attention to the subs so away they went.  Decent floor standers should stand in their own, IMHO.  The only add-on I can offer is never underpower speakers. Error on the side of max wattage.  Aside from class 80 watt A monos and an A21, I have the Bel Canto M1000 class D monos and the extra power is more than sufficient to drive most average sensitive floor standers.  Bass is more than a range of frequency response, it's various low frequency instruments. I'm more interested in and pleased with accurate reproduction of instruments, not just 'bottom end'. 
If aesthetics and convenience allow, I have used a 1/4" dowel rod in upper back of speaker to brace the cabinet against the wall, with slight tension by
tipping. It is cheap, reversible, and sometimes works very well. Good luck!

A friend of mine once showed me how he can get a great bass using an Equalizer. The difference is night and day, very impressed. Unfortunately I do not have enough knowledge doing it.