uhm yes. im not sure what your point is (i think we do not understand each other correctly). when i say drum. i dont want to make it sound like a drum... the working is the same as a drum.. with a main resonance etc. thats the way it is if you strech any membrane suspended you get a drum. sure a drum has a housing etc. but same rules apply. not much output under main resonance.. and huge peak at resonance. now the task at hand here is damp main resonance and or get main resonance as low as possible in this setup. to much damping sounds poo and hurts other frequencies as well. to little and you still have a peak.
if the resonance is to high in frequency the peak is even more anoying. and well you cant go much lower then that. since the dual foil halves the damping from the air it normally gets.. a panel must be wider then usual, or less streched.. less stretch gives other distortion problems, it moves less nicer together with the other foil. my theory, is larger foil and firm stretch.. downside is it gets big. noone likes wide... and making it biger vertical does not do as much, since that direction already is lower in resonance then the main combined resonance of vertical and horizontal. so the only size that dictates the resonance is in this case the width
i could try different tensions horizontal and vertical, that might fix some problems of less tension overal.. but i doubt it
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well this one made a complete mess
so that does not work haha, i think regular or maybe even more round or oval... might even work betterif i would make it a circle... resonance will get even a bigger problem though
I had an email with Rob Mackinlay from ERaudio about the subject of introducing central excursion corrective gradients into a planar membrane's drive. At first sight, it appealed to me as to be a very insteresting approach, potentially even rising the overall max. SPL capacity of a planar. Because you could drive it harder until the central parts slam onto the stator/magnetic array. However, one of the conslusions I made after my exchange with Rob is that you go may run into more trouble than you may solve with any driving gradient. Homogenous drive still seems overall way superior.
Several examples of non-homogenous drive methods have already been enumerated here in this tread, such as beating a drum by a stick, adding central weight to the membrane, leaving a central drive hole in the stators/magtnetic array, and the like.
Surprizingly, the most evident and widespread example of uneven drive has not been mentionned yet: The one in standard magnetodynamic cone/dome drivers. A dome is not driven centrally. And a cone is not driver in periphery. So there is a clear drive gradient along the membranes in these examples. All these unevenly driven membranes will break into submodes, as shown in the youtoube videos, and as known from cone and dome breakup in magnetodynamic drivers. Therefore, with a drive gradient, you will basically trade in one of the main benefits of even membrane drive over it's whole aera.
In terms of resonant sub-modes, any drive gradient will to some extent reduce the benefit of magnetostats or electrostats elegant homogenous drive to the potential mess you have with cone breakup issues in traditional cone or dome speakers.
Don't. It would be a pity to treat planars like this ...
Several examples of non-homogenous drive methods have already been enumerated here in this tread, such as beating a drum by a stick, adding central weight to the membrane, leaving a central drive hole in the stators/magtnetic array, and the like.
Surprizingly, the most evident and widespread example of uneven drive has not been mentionned yet: The one in standard magnetodynamic cone/dome drivers. A dome is not driven centrally. And a cone is not driver in periphery. So there is a clear drive gradient along the membranes in these examples. All these unevenly driven membranes will break into submodes, as shown in the youtoube videos, and as known from cone and dome breakup in magnetodynamic drivers. Therefore, with a drive gradient, you will basically trade in one of the main benefits of even membrane drive over it's whole aera.
In terms of resonant sub-modes, any drive gradient will to some extent reduce the benefit of magnetostats or electrostats elegant homogenous drive to the potential mess you have with cone breakup issues in traditional cone or dome speakers.
Don't. It would be a pity to treat planars like this ...
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