Right NWBasser. I have heard about long excursion speakers and their ability to push more air and handle bass better. However, I don't think that a long excursion speaker can increase the amplitude of the wavelength. It can reproduce a longer wavelength better possibly and definitely give you more "thump", but I don't think it can increase the amplitude and give you as deep of a bass tone as a fifteen or eighteen inch speaker of the same ratio long excursion speaker.

It is confusing though, because my Klipsch eight inch subwoofer I added to my home theater system sounds really good. Better than the bigger subwoofers I tried that were within my price range. I paid more for the Klipsch but it has more controls and switches on it than any of the other ones and it is a down firing one. A down firing one might use the floor to create a larger "sounding board" for the sound waves to get attenuated by and then re-radiated by, causing it to sound like a larger speaker. Plus, for a bass speaker wavelength to really sound correct I have heard that the room you are in has to be pretty big in order for the bass wavelength to fully reach the actual measuremed wavelength.