Slightly used Legacy Focus meet your requirements. Either two or three 12" woofers per speaker. (The older models have three per speaker, the newer ones two.) 95db/2.83v efficiency, so your watts go a long way. I don't know of any other speaker that moves as much air for the price, without a dedicated subwoofer. Pretty good sound overall.
Legacy Focus 20/20 or Focus HD (earlier versions had loose bottom end IMO -- 20/20 and HD versions corrected this). Big sound with abundant bass and good musicality -- very dynamic (both need strong solid state amp to control the woofs--pair with a good tube preamp and this is wonderful rig).
Vandersteen 5A will perform true 20 hz bass in your room They feature a self powered double cone metal 12 in a sealed enclosure with a unique tuning feature that will optimize the quality of the bass in your room this enables the mid bass,patented mid-range, and treble drivers to sit on a bass coherent foundation allowing you quality performance and coherence at all volumes. Johnnyr
A speaker with a really deep bass, then look no further than a B&W 801 Nautilus. I have had the B&W Matrix, Series 3 and 801 Nautilus. Matrix 801 had pretty good bass with a 12-inch driver, but the 801 Nautilus was really something else with a 15-inch driver. The 801 Nautilus' bass was incredible and amazing. The bass strings on jazz recording really come alive...
I have auditioned Wilson Watt Puppies many times. They have pretty good bass, but not as powerful as the B&W Nautilus 801. Now if you are looking more for quick dynamics and transparency, Wilsons are hard to beat.
I have since moved on to Avalon speakers, but still miss the bass on the 801 Nautilus I used to have, and not by a little but by a lot!!!
However, I think trying to produce good bass from a floorstanding speaker is a flawed notion since you can not position the speakers where they need to be for good bass. I'd consider smaller higher quality main speakers with multiple subwoofers.
However, an exception to my comment are the larger Vandersteen speakers that have builtin EQ to address the position issue. Richard V is a smart man; makes the only bass limited stand mount speaker I know of.
Easy answer: B&W 801N or the original Revel Salon, both available within your price range.
The B&W needs to be bi-amped to sound right - it requires an enormous amount of power.
The Salon can go incredibly loud with really high quality bass, and also requires a lot of power, but doesn't require biamplification. If you like 4th order crossover speakers, it is hard to beat, and at used prices, it's an enormous bargain, as it is an excellent speaker.
Large drivers are not necessarily needed to achieve deep, prodigious bass - the quality of the drivers and their implementation is what counts - but yes, larger cones are generally better.
The ability to produce "deep and abundant" bass in a room is a combination of the speaker design/performance and the room design/performance. At one point some years back, I had Vandersteen 2CIs in an 18' x 35' room with a cathedral ceiling and the bass by far exceded that of my friend's Vandersteen 3A Sigs with 2WQ subs in a 20'x 20' room. Keep in mind that you need to explore more than just the speaker to achieve your goal.
"The CS7.2s bass depth and authority are shattering, and its bass weight is wholly realistic not warmed up to create a sense of fullness or heft from recordings that dont have it by nature. Bass notes are carved out with exceptional clarity, even at the speakers very depths. Claims of 20Hz bass are common today, but if the CS7.2s 25Hz low-end specification is correct, many speaker companies are exaggerating. From my experience, you have to pay several times the CS7.2s price to rival its deep, linear bass."
"Thiel speakers are known for excellent bass, but the CS7.2 was even better than I'd expected. From the mid-20Hz range on up, it was fast, clean, powerful, and very naturalin other words, dead on. Detail was excellent, as was the recovery of ambience and spatial cues. On "Saturn," from the Zubin Mehta/ LSO reading of Holst's The Planets (London/Classic CSCD 6734), I could clearly hear the individual double basses lined up at an angle. The walls beside and behind them were solidly located, and there was a great sense of the space between the instruments and the walls.
Fast, melodic bass linesRay Brown's Soular Energy (Concord Jazz CCD-4268), for examplewere sweet, clean, and bouncy. But what really struck me was the 7.2's reproduction of bass drums, and the breathtaking drive and impact that it added to orchestral pieces. My notes on the second movement of the Reiner/Chicago performance of Prokofiev's Lt. Kijé (Chesky RC10) say it all: "Wowincredibly realistic, with a fast initial transient followed by a seismic, blooming weight . . . all the while maintaining a clear pitch, harmonic structure, and distinct skin tone. Fantastic! I've never heard bass drums like this outside of a concert hall."
The only nit I'll pick is that the 7.2 slightly emphasized the very lowest bass relative to the upper bass and lower midrange. This didn't come across as an imbalance or discontinuity, however, but as if Ray Brown just wasn't playing quite as loudly at the top of his range as at the bottom."
I am really looking forward to the CS7.3 that is coming out down the road...
Pick a pair of floorstanders that you like, and add a pair (or a stacked pair on each side) of JL Audio E112 subs using the crossover built in. Cross over at around 80hz regardless of speaker size (don't just add them in where the mains roll off) and you will have better bass than almost all stand alone speakers made if done right.