Posted by GarMan [ 216.13.136.38 ] on June 06, 2005 at 08:38:27:

In Reply to: Excellent job posted by wunhuanglo on June 06, 2005 at 05:50:06:

Finding ways to get the shape was easy. Building something to hold the piece while shaping was hard. I didn't exactly want handhold a piece 5/8" wide next to a blade spinning at 5,000 rpm. Took a few tries on a workable material. It only took two kick-backs while shaping the stacked plywood to convince my to switch to a softer material. For some reason, the laminate bit kept grabbing the ply and ripping it out from the jig.

I've been keeping my eyes out for a used pair of 2397 on eBay for a while, but they've been coming in a $500 a pair. I'm convinced I can make a better one with $50 of material. For example, I read that JBL purposely builds the input mouth of the horn larger than the opening of the throat adapter (horn mouth is 4", throat is 3.75"). This is to account for the poor tolerance in the adapter casting, so that even as dimensions vary, the adapter opening will never be larger than the one on the horn. For this horn, I'm building the opening to exactly match the adapter to ensure smooth transition.

gar.

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