Why is good, deep bass so difficult? - Myths and their Busters

I have tried to imagine what is meant by fast or slow bass. It cannot be the speakers themselves for reasons that have been explained. My hypothesis is that what people are referring to is really the delay that is visible in waterfall graphs of bass response in real rooms: the reflected sound of room modes lingers on.
When I added a B&W PV1d subwofer to my Quad 2805 electrostats I was disappointed at first, even though the room is large. The bass did indeed sound slow and woolly - not at all like the bass that was coming out of the stats. When I added an Antimode 8033 dsp room equalizer the problem was gone, and over a pretty wide area. So it was not the speaker that as slow, but the sound.
My take home lesson has been that room modes can indeed be a big problem. In a small room it is not a good idea to even try to reproduce deep bass. In a bigger room, with room modes at lower frequencies, the problem is less (the Schroeder frequency is lower), and equalization is easier and effective over a wider area. The second lesson is that dual subs are advisable, and preferably combined with a room eq system such as the Antimode 8033.

Duke,
Your Swarm system is indeed interesting and sounds like the theoretically correct solution, even if one with rather a lot of boxes in the room. In my case, I think I will continue to save for a second PV1d, used with the Antimode, as a domestically acceptable compromise (the big stats have already been pushing the boundaries). Did you ever compare (and measure) your Swarm used with room equalization?

Hence the need for a low output impedance (which is a different way of saying the same). If the damping factor is too low, the frequency response becomes heavily load dependent, with potentially exaggerated bass or high frequency roll off (or other anomalies). Typically, this is not a problem with the better solid state amplifiers, but it is with tubes. Perhaps that is why some audiophiles like them.
EDIT: sorry this was a response to an earlier post about the need for a high damping factor.

Duke,
Thanks for coming back to me. That sounds like a nice flat response, but it is of course room specific, and not always achievable. You are right that since multiple subs give a flatter response over a far larger area, the potential for equalization is even greater. So I guess the right answer is to get the basics right by using more than one sub, and not shy away from some smart equalization either, particularly now that units like the Antimode 8033 are so easy to set up, and so cheap.

Really?