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!

All great suggestions from everyone and each in it's own way will add its own incremental improvements to your in-room bass response. I was in the same spot as you (and also own and use Tannoy D700's) but I didn't get the bass I was really looking for until I added a subwoofer. Good luck!
I have Westminster GR in a good size room that is engineered and treated. I added Audiokinesis Swarm subs to add that last bit of low end I wanted and could not be happier.  Yes, there are 4 but their footprint is small and integration is seamless. Adding this to echo Mike on not ruling out subwoofer as the answer. 

Good luck on finding your solution and happy listening!
I love the CJ Premiere 12's by the way. One of my all time, if not all time favorite amplifiers. If only money and space allowed!