Help in understanding this baffle effect

ironsf

Member
2014-02-17 5:46 pm
Yavne
Hi
I mounted a tweeter "dayton-audio-ND25FA" once in a test box where i tested the mid and one in the final box design. (the test box was intended to the the mid only but i mounted the tweeter to get an idea of how this speaker will sound)

See attached measurements and images.

in the test box it case a and in the final box it is case b.
in the measurements the orange is the test box (case b)


Case B looks very bad. but it does not look like baffle diffraction loss.

just a note on the image you see with the final box:
it is on a shelf close to the wall because i want the destine the xo with measurement of how this unit will be placed when it is ready.

when removing the shelf it did not to any effect on the tweeter measurement (as expected i guess)

Thanks
Ran
 

Attachments

  • tweeter.png
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  • Case A.jpg
    Case A.jpg
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  • Case B.jpg
    Case B.jpg
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  • dim.png
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turk 182

Member
2012-10-26 3:03 pm
so what is baffle diffraction supposed to look like?


and there's a big difference between the "test" situation and the "final" with respect to additional surface area around the tweeter, then add the distance to boundaries i.e. the test case(free space) versus the "final" (against a wall).


but if your looking for other possibilities the only thing i would look at is x-over summation.
 

giralfino

Member
2009-02-28 9:20 pm
I don't know if your measure is gated or not, but I suppose isn't. If so repeat with a necessary gate.
Looking at the manufacturer's datasheet, taking into account the very different grid between yours and manufacturer measures, probably your measure B is how it is supposed to do, and the effect you see could be simply the effect of a non damped resonance. Maybe the resonance of your tweeter is higher than specs at around 2KHz, if possible measure impedance too.

Ralf