Optimum driver height in open baffle

[ralphs99]

I've been doing some experimental studies with sealed boxes and open baffles.
I've found relatively more erratic room interaction with my test open baffles where the drivers are spaced close to the floor compared to a similar driver layout in an sealed enclosure.
Increasing the driver distance from the floor made a remarkable difference for the open baffle. I get proportionately better results the closer the drivers are to the centre point between floor and ceiling- except right in the middle.
I'm trying to understand why this might be so....
I figure that with the drivers near the floor (in any case really) the transverse room modes are being excited to a lesser degree accentuating the other room modes giving a more erractic response. With the drivers away from the floor some dipole action may also be occuring in the vertical direction as well reducing the influence of room modes along that axis. All that remains then are the room modes in the axis between listener and speaker. These are perhaps better controlled relative to the other axial modes becuse of the listener's (me!) position close to the rear wall.
Would anyone else care to put forward an hypothosis? Or share their experiences with driver placement on open baffles?

Cheers,
Ralph.

[Paul H]

Ralph,

Your theories make sense, but I don't know if anyone's tested those ideas much.

When I was initially designing and testing for my dipoles I tried many different baffles, but generally adjusted width and chamfer/roundover settings. I didn't change the height from floor significantly because I didn't have much room to play with given my large full-range tower design.

Paul