The mains must be placed at the best non-modal location relative to the room boundaries for the best direct field response, i.e. best image. This may or may not result in the best locations for the LF modal region frequencies. To this I add two smaller subs - one above the mid line of the room and another as far away from the mains as possible. These subs cover 35-120 Hz yielding about five speakers (center channel if used) at near random loactions covering the range from about 35 Hz and up. So where the mains are placed is basically irrelavent for the LF modal issues. I now add a single VLF sub to cover the 25-50 Hz region that the Summas can't reach. So only the frequencies from 25-35 Hz are not covered by several drivers, but at these frequencies the wavelengths are so long that it isn't possible to get multiple uncorrelated drivers anyways. This configuration yields the best LF response that I have ever obtained in a small room.

So basically the room has 1 source 25-35 Hz, three sources 35-50 Hz, and four or five sources 50-120 Hz. Sure it would be great to have 5 sources 25-120 Hz, but thats not feasible. What I have is not only feasible and low cost but only one of these sources is even visible.