question re: poor bass response

In the good old days preamps had a "Loudness"control which automatically boosted the bass as volume was lowered. It was based on the Fletcher-Munson curve mentioned above. Audiophile purists stamped out Loudness controls, along with Tone controls on most preamps, and they also frown on equalizers. If it really is a low volume problem, a subwoofer will not solve it. You need bass boost, over more than subwoofer frequencies, and an equalizer may be the only way to get it.

I also was plagued by a poor bass response at low and mid volume levels with my B&W CDM9 NT floorstanding speakers. I improved upon this dramatically by uncoupling the speakers from the floor via soundcare spikes. I received a welcome increase in bass at all levels. Then I added a Krell integrated to my set up. Once again another improvement in bass levels.

Are your speakers on spikes or appropriate stands? Also, is your amp up to the task?

Newbee, the room is probably an audiophile's nightmare. Overall dimensions are ~40x18x9 but a partial wall separates the listening area (24x18x9) from the adjacent "room". The speakers face the length of the room, sit about 10' apart and 3' in front of a set of built in shelves/bookcases.

Hammergjh, speakers are on Sonus stands with spikes, so isolation shouldn't be an issue. I'm curious, what amp did your Krell replace and why do you think the Krell gives you better bass levels?

The Krell replaced an Odyssey Stratos. Krell amps are known for their prodigious base response, and now I know why. The bass became palpable at all listening levels but very balanced, not overly pronounced. The difference between the amps was striking. I'm not knocking the Odyssey, but I never felt the Odyssey handled the woofers that well and the Krell handles them like a champ.

I suspect that your speakers are too small to properly provide low bass in a room as large as yours, let alone full sounding bass at low volume. Even with full range floor standers you would need some means of elevating the bass level due to the F-M curve discussed above to get good bass at low levels. Despite comments to the contrary, it is possible to utilize a sub woofer - it all depends on the crossover and amp which you use on the sub woofer. My objective would be to have a sub which operated independly of the main speakers and didn't start to roll off the high frequencies until 100 hz - that way you could turn it off for high levels of playback. If you don't want to invest in a sub woofer, equalizers or tone controls are your only answer, short of buy new speakers and amp/preamp.