Is Anyone Using Subwoofers the Same Size as Their Mids?

Ever since I moved my listening room, I’ve been struggling with subwoofer integration. I know there are several room-related problems I need to solve and in the meantime, I am not using a subwoofer. Recently I made some system changes and realized my 6.5” mids actually put out some decent bass and because they don’t dig quite as low as a true subwoofer, they (mostly) get around the room issues. It made me wonder if I could simply add more identical drivers (6.5”) and tune them to subwoofer frequencies (e.g. high pass at 80-100 Hz, for example). Perhaps even get four of them and build a distributed bass array. In theory, they should integrate beautifully with the mids since they would be identical drivers. What am I missing because this seems like too good of an idea for other people not to have done it? Does anyone have any experience with this? 


Thanks for the input. I have the tools to apply EQ with a calibrated mic and a DSP module. I’m not sure how far that will take me because I have some serious issues with the room. For example, if I bang on the drywall I can hear it rattle while it produces a super low frequency note of its own. What I need to do is screw down the drywall better and add insulation to the studs. I’m dragging my feet a little because I don’t really want to patch and paint all the screw holes and if I’m going to do that do I just tear down to the studs and build a proper wall from scratch? That’s probably the right answer. 

This is from Earl Geddes’ Premier Home Theater that’s an extremely useful resource.  If you skip to chapter 11 he goes into wall construction.  In short, using a damping material like Green Glue or Liquid Nails when putting up a wall can be very effective, but using a damping material between two wallboards is even more effective.  Anyway, hope this helps…

I use four 10" diameter subs in my system.

Depending on which speakers I'm using, my midwoofers range from 10" to 15" in diameter. 

In general, subwoofer drivers are optimized for subwoofer frequencies, and midbass drivers are optimized for midbass frequencies. While in many cases each "can do" the other's job, imo that's probably not going to be optimum.