Bolt Hole Spacing - HOW to fit a 515B into a 828 enclosure

[LowOhms]

Good Q, I don't remember this as the few 828s I messed with all had 421s or similar, but I surely knew about the different frame sizes. Guess I either never had to deal with it or the early 828s had both patterns. Anyway, just off the top of my head, I'd grab a scrap strip of wood, lay out both bolt patterns on each side, use the outer ones to pin it to the baffle, mark/drill the other two, remove strip, use the inner ones to either hold the driver as template or use some scrap hardboard/whatever to make a permanent template. Come to think of it, this was how I remember doing some different horns and seems like I rotated the pattern a little to get more 'meat' between them.

GM

Hi GM and thanks for taking a shot at this.

I posed the question to my good friend and audio buddy, Dennis Fraker of Livingston, Montana ( Serious Stereo. Com ) who runs GPA 604s in MLTLs, after I posted my inquiry here.

Dennis suggested having a 1/4 inch Aluminum ring plasma-cut to fit the stock 15 1/8th inch diameter 828 hole spacing, countersunk for 1/4 by 20 machine screws, and a second set of 4 holes, 45 degrees apart from the 828 holes, tapped 1/4 by 20 at the 515B's 14 9/16th diameter, to attach the 515B frame. So far, that seems the best way I can think of doing it. There will be just enough room in the rear compartment of the 828 enclosure to fit the deeper frame of the 515B driver.

I wonder if anyone else in ALTEC-land can come up with an even better "fresh" new solution ??

Cheers and thanks to all,


LowOhms ...................aka ...............Jeff Medwin