Originally Posted by desertdome
I have line source speakers (GR-Research LS-6) that have bass extension to 20 Hz in my room. Like Bill said, the drivers become mutually coupled point sources at some point. I also have infinite baffle manifolds located just outside and a little behind each speaker. From around 120 Hz and down, both the speaker and IB measure the same due to the room modes even though one is firing up from the floor and the other is in a line array extending over 5' above the floor. I think this illustrates Bill's point.
Interesting. I would never guessed this could happen.
If I understood Bill correctly, coupling in multi driver subs is not the same as point source summing. With coupling, the output is increased but it does not mean that all drivers share single acoustic center.
Whenever I am doing (RTA guided) sub crawl, I see that a few feet can make a difference, sometime big difference, in frequency response at the MLP. I explained this by the differences in boundary reinforcement and what room modes get excited at any given position.
So, intuitively, I thought that while a multi driver subwoofer and a hypothetical single driver one may have the same SPL, they will have different FR due to the room interactions.
Apparently this is not the case at least in your set up. I still do not understand why though. For example, a wall-to-wall multi driver unit would load two corners, something that a single driver sub cannot do. That's why I believed that Bosso's 4 stacked units could provide some modal smoothing though probably not as effective as properly executed mutisub with individual units decorrelated from each otherEdited by zheka - 1/3/13 at 11:45am