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Taming/Damping Electrostat Backwave

In my understanding of the physics of the situation, the signal coming off the back of an electrostat panel is the same signal that comes off the front though in opposite phase. If there are reflections off a back wall, they cannot be a better signal than the one off the front of the panel. It strikes me that in a strict sense, if one could COMPLETELY eliminate the backwave on electrostatic speakers (a giant silent sound vacuum, sucking in the sound off the back of the dipole), this would be, in the words of the once famous and now infamous [:)] Martha Stewart, 'a good thing'. Am I missing something? Is there any argument to support not trying to eliminate the backwave through all means possible?

My Martin Logan SL3s sound reasonably intolerable when too close to the back wall, great when a certain distance away, and in my limited, ad hoc, distinctly non-scientific (not to mention bad WAF) experiments, even better when I put a variety of dampening material between the panel and the back wall (even when the wall is 6ft back).

Does anyone have a view or experience on the "complete backwave elimination" strategy? Do you try to eliminate it entirely? Do you leave some backwave in for 'flavor'? How do you deal with it? Put shag carpeting on the wall? Hire tall sheepdogs to sit on stools calmly for hours on end a la Fay Ray? I would love to know how other people deal with the backwave issue...
t_bone

Showing 1 response by newbee

newbee
4,751 posts
 
tom, my experience with 63's was some what parallel to your's but with different results. I tried deadening the back wave, partially and totally with poor results. I ended up with the speakers about 4 1/2 feet from the back wall toed in about 15 degrees with the back wave firing into irregular materiels, i.e. books, plants with round plant stands, etc including the corner of the room. the speakers were firing down the length of the room to a listening position 4 1/2 feet from the back wall. Gsreat result w/ flat bass/midrange frequency response.

Dennis, when you pulled your speakers out 7 feet from the wall you may have successfully eliminated any bass reinforcement from the nearby walls - this would emphasize the upper frequencies and make them sound thin. most manufacturers assume that there will be wall reinforcement, especially in smaller systems w/cone speakers(as i recall your speakers have a dynamic woofer?).
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