I've managed to achieve fairly flat/clean response in my 15.5ft x 10.1ft room down to 22Hz, but I'm using four 12" woofers and lots of power to do that at greater than 90dB.
What I've found is that interesting musical content below 40Hz is uncommon. Most of what I hear is stage/studio vibrations, an HVAC switching on, a truck driving by, or other low, rumbly noises that were picked up by the mics during recording and not filtered out. While these sonic artifacts are occasionally interesting, they rarely contribute to the musical performance in any helpful way, so I'd probably be better off rolling things off sharply below about 32Hz. Here's a graph of actual measured response at the listening position before and after correction:
http://www.dsnyder.ws-e.com/photos/potn/Loft_Before_After_and_Target.png
Here's a photo of the actual room from the listening position:
http://www.dsnyder.ws-e.com/photos/potn/loft_wide.jpg
I'm confident that I could achieve similar response with somewhat smaller loudspeakers, but I estimate that minimally four 10" woofers or two 12" woofers would be required in total to achieve this level of bass extension without a separate subwoofer.
I had these loudspeakers before the room...they are obviously a bit large for the space, . If I was buying loudspeakers specifically for this room, I would probably have chosen Harbeth 30.1 or Legacy Audio Calibre and would have been quite happy.
What I've found is that interesting musical content below 40Hz is uncommon. Most of what I hear is stage/studio vibrations, an HVAC switching on, a truck driving by, or other low, rumbly noises that were picked up by the mics during recording and not filtered out. While these sonic artifacts are occasionally interesting, they rarely contribute to the musical performance in any helpful way, so I'd probably be better off rolling things off sharply below about 32Hz. Here's a graph of actual measured response at the listening position before and after correction:
http://www.dsnyder.ws-e.com/photos/potn/Loft_Before_After_and_Target.png
Here's a photo of the actual room from the listening position:
http://www.dsnyder.ws-e.com/photos/potn/loft_wide.jpg
I'm confident that I could achieve similar response with somewhat smaller loudspeakers, but I estimate that minimally four 10" woofers or two 12" woofers would be required in total to achieve this level of bass extension without a separate subwoofer.
I had these loudspeakers before the room...they are obviously a bit large for the space, . If I was buying loudspeakers specifically for this room, I would probably have chosen Harbeth 30.1 or Legacy Audio Calibre and would have been quite happy.