Jacek
I caught the compression ratio error and corrected it (almost) immediately if you look back.
Yes, now you have it. What does the other side of the pase plug look like?
I caught the compression ratio error and corrected it (almost) immediately if you look back.
Yes, now you have it. What does the other side of the pase plug look like?
Why such a low compression ratio? Not a good idea IMO. Compression ratio is basically where most of a compression driver/waveguides improved efficiency comes from. Its that efficiency that is the attraction (that and directivity control of course). Basically with CD you need all the efficiency that you can get at the top end. In my speakers the DE250 is running unattenuated at 10 kHz. Lowering the compression drivers efficiency would require the whole system efficiency be lowered. And for what gain? Lower distortion? Not a good trade off since distortion in a compression driver was shown not to be a subjective factor (see my AES paper on this).
Can you make one of these for a DE250 to? I think some of the Geddes customers will be interested in trying this one...
Looks a lot like the Klipsch K1132 phase plug...
Just a thought, but what drove the decision for three braces?
Just a thought, but what drove the decision for three braces?
I have no drawings of the DE250. I will try to find them, but maybe Dr Geddes can help with this, as believe he worked as a consultant for B&C and still has good contacts with them.
Any picture of K1132? Braces - phase plug is brittle (nothing decisive).
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Sadly I don't have any pictures, but one difference I see is the K1132 phase plug is shallower on the edges, and was designed for a 2" throat. Basically more the shape of an american football when viewed from the side. I do know the designer was treating the area expansion inside the phase plug as part of the horn, but the overall concept is very similar.
My only thoughts with the braces were in consideration to staggering them between rings (which I think the K1132 does), or perhaps looking at the interaction into a rectangular horn to see if there might be any potential advantages there.
CAD drawing of DE250 based on measuring them with the calipers. It was hard to measure the exit tube, so that is the least accurate part - a shame because it is also the most useful part!