Open Baffle Experience

@jaytor , I am a huge open baffle fan. I have been using open baffle loudspeakers exclusively since 1979, they are called ESLs. They are full range (except sub bass) line source dipoles. The entire range from 100 Hz to 20 kHz is open. I also have been building subwoofers since 1993. You can see my shop on my system page.

Granted, subwoofer enclosures are a royal PITA but trying to use an open baffle driver at wavelengths between 10 and 40 feet is a hopelessly inefficient way of going about making sub bass. What you have are floor shakers. It is also not about what you hear down there but what you feel. Who knows? Given the crappy construction quality of most subwoofer enclosures you might be better off where you are.

@jaytor , get yourself a measurement microphone and have a look. Yes, you have bass but it is wildly inaccurate. Bass is very deceptive. People will swear they get great bass out of little loudspeakers. What they are getting is the illusion of great bass. Servos on subwoofer drivers seems to make a lot of sense. The problem is that they do not take into account the resonance and movement of the baffle or the cancelation effects of an open baffle. Play something with a really low note like an organ piece and put your hand on your baffle. That vibration you feel is distortion that the servos cannot account for. The other problem with servos is that the best large subwoofer drivers do not have a problem with distortion. Distortion only becomes an issue with smaller drivers trying to make sub bass. They have to move so far to do it that their suspensions become non linear.  To tell you the horrific truth most enclosed subwoofers are not much better. The best subwoofers are going to be balanced force designs with extraordinarily stiff enclosures. The Magico Q series is a good example. Kef Blades use a balanced force design. You should be able to put your hand on a subwoofer while playing and feel absolutely no vibration.  

I have built two sets for friends using Focal drivers at a time when they were still available. Both of them were coupled to sealed subwoofers. The baffles were a Corian sandwich with MDF in the middle. They were two way with a very straight forward 12 dB/oct crossover. The baffles were hung from the ceiling using decorative chains and the subs were just underneath. They were in essence open baffle LS3 5As. They sound much larger than they are. The owners are very happy with the results. 

Building an open baffle system is much easier than trying to build a non resonant box and the open midbass/midrange driver makes the speaker sound three times as large as it really is. Open baffle subwoofers is a patently silly proposition. I have tried it and the results are poor.