Is the maximum frequency of AMT driver limited by plead depth (1/4 wavelenght)?
I was thinking of AMT ribbon plead geometry and I become concerned how depth of pleads could affect the sound. Becose once the plead starts pumping the air, the sound from the opening part of the plead, the closest part to air of listener will arrive sooner than sound generated at the bottom, the deepest part of the plead.
As long as the frequency is long enough compared to fold depth, all is ok but when the fold depth becomes half as long as wavelenght it tries to reproduce, it will take so long for sound from the back of the plead to travell to the opening/front of the plead that at that time, the plead is moving at 180 degrees out of phase which I expect will cause significant phase cancelation, I expect the frequency reponse above 1/2 wavelenght to have comb filter like response with deep nulls due to phase cancelation.
Is my theory correct or does this not matter and you can make for example AMT tweeter with 1 inch deep folds and have it be flat to 20KHz?
I asked ChatGPT and it told me about the 1/4 wavelenght limit which is 4.2mm for 20KHz.
I was thinking of AMT ribbon plead geometry and I become concerned how depth of pleads could affect the sound. Becose once the plead starts pumping the air, the sound from the opening part of the plead, the closest part to air of listener will arrive sooner than sound generated at the bottom, the deepest part of the plead.
As long as the frequency is long enough compared to fold depth, all is ok but when the fold depth becomes half as long as wavelenght it tries to reproduce, it will take so long for sound from the back of the plead to travell to the opening/front of the plead that at that time, the plead is moving at 180 degrees out of phase which I expect will cause significant phase cancelation, I expect the frequency reponse above 1/2 wavelenght to have comb filter like response with deep nulls due to phase cancelation.
Is my theory correct or does this not matter and you can make for example AMT tweeter with 1 inch deep folds and have it be flat to 20KHz?
I asked ChatGPT and it told me about the 1/4 wavelenght limit which is 4.2mm for 20KHz.
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