Hi Malboro The four subs are not the for high SPl, but for improved in room responce.Four subs iddling sound far better then one vented box leaving its gap and farting away.Allways been partial to the sound of TL's. Are you into experimenting? If so PM me and I send you some tweets to play with.I too started out with domes,but found them lacking in top-end when used in line arrays.Have planars now but think found somthing better yet.Not ready for the world yet but I would love to get another opinion. Sunny