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RE: Beryllium Dome

In the case of the JBL 2441 mounting as a midrange for a Edgar horn, the increase in detail is stunning. The driver sounds more like an electrostatic driver in being extremely revealing and extremely quiet, for some reason. Of course it still has the tremendous dynamic range, but has a greater sense of "ease" as the dynamic range increases, probably as the beryllium is much stiffer than the aluminum and thus less prone to distort.

The original 2441 has a tiny pad glued to the tip of the dome, which I suspect is similar to aluminum domed tweeters having the little pad on the front of the diaphragm, on the sort of "bull's eye" extension. Even the Seas tweeter with the mesh grill has a small about 1/4 inch plastic dot on the center, the purpose being that the dome has a lot of distortion on the dome tip and the slight air pressure build up will dampen that distortion. The replacement beryllium diaphragm has not such pad, BTW.

I do not know if a beryllium replacement is made for the 288 as it is for the 2441. They are roughly similar in size ( the JBL is about an inch bigger)and both employ edgewound voice coils.

Be aware the beryllium replacements for the JBL were on sale for $600 a piece. I believe TAD also makes replacement beryllium cones, but I am not sure if their sizes will work in a 288. Rumors have it that TAD hired a female JBL engineer and gave her carte blanche to create drivers to surpass those of JBL and Altec.

After listening to before and after on the 2441 replacements, I am most certainly impressed with the difference in the choice of material. However, the issue then becomes how to up the signal quality of the lower driver (D131) as the midrange is now so good the speaker reveals a certain lack of coherency.

of course YMMV


PS The manufacturer was truextent and their website claims they are working on smaller domes.

Edits: 03/14/12

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  • RE: Beryllium Dome - unclestu 15:25:25 03/14/12 (0)


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