Internet Direct companies like: Power Sound Audio, Hsu Research, Rythmik, SVS, and Outlaw Audio offer the best bang for your buck. They can do this because of 2 facts: (1. they have no middle man because they sell direct over the internet, and (2. they have industry leading professional engineers and designers running them.
Klipsch among other brands tend to exaggerate their specs and frequency response compared to what real measurements and graphs show. Now for $600 the Rythmik LV12R will give you REAL and USABLE 19hz output. Below 20hz is where bass really becomes fun because thats where bass is more about feel than sound.