Shelf braces for KLF 20 and air flow.....?

[Klipschtastic]

Last night I removed the loose front baffle from my first KLF 20 to be repaired. I have a sheet of 3/4" thick oak plywood to make braces with. I want to make the shelf brace type where I essentially make a shelf and cut out the center leaving about 2.5" wide bracing around the perimeter. The problem is my speakers already have lateral bracing running between each woofer which is 3/4" thick and 3.5" wide. The perfect placement for the shelf braces would be to lay them directly on top of the existing braces. This would occlude much of the air passage between the woofers. It would only leave about two 1.75 x 7" inch areas of portage for air to flow through the cabinet. Is this a problem? Should I remove the existing braces and just install my shelf braces?

Also should I add a third shelf brace between the mid and tweeter?

I am of course going to add 3/4 x 3/4 braces along the perimeter of each baffle to glue them to and I've snded the melemine of contact areas with a dremel.

I hate to ask so many questions but I really want to do this right and only once....lol.

Thanks

Jon

[pzannucci]

You would be fine though you really don't need to leave or make the braces 2.5" thick. 1.5" with a t or cross pattern should be good enough. Then you could add multiples.

[longdrive03]

You could just attach your braces to the top or bottom of the installed braces, glue, staple/screw together and the cutout the installed brace to conform to your new brace. I would uses some 3/4" square glue blocks on side of cabinet using PL Premium adhesive attached with screws, glue it all together let adhesive dry and the cutout old brace. Just a thought.

[moray james]

the optimum size for brace width is about 3 times its thickness. Lower the ratio lower the strength and if you increase the ration you are taking up additional cabinet volume with no benefit as it won't be stiffer. Braces are about stiffening the cabinet, you want the most stiffness using the least volume of material. Hope this helps Best regards Moray James.

[Klipschtastic]

Thanks for the replies. I have finished all the bracing. I have actually been working on the speakers for the past week or so. I had done a spot repair a couple of years ago to the rear baffle of one speaker with 3/4" perimeter braces and reglued it. I removed both front baffles; it took about 15min for each one with a stiff putty knife and a heat gun. I tried to remove the one untouched rear baffle but it was tight so i decided to sand the melamine and just glue the 3/4" corner braces.

I looked up an old thread on audiokarma where a member did a write up with pics on the same job. I modeled mine after his using 2.5" wide by 3/4" thick pieces of plywood running front to back crossing over the factory bracing in two spots, between the two woofers and between the top woofer and mid driver. I ran a 1.5" wide rib across the front and back baffles forming an I-beam pattern if veiwed from above. I also added a third brace below the lower woofer. I ran 3/4 x 3/4" strips around the perimeter of the openings to glue the baffles to. That melamine sure does kick up a lot of dust when sanding. My garage looks like Mt. Saint Helens and I looked like a coal miner.

I just finished stripping the black paint the previous owner put on over the original Light Oak finish. It was dull and chipping. I still need to sand a little before restaining. I'll post a few pics when finished. I didn't document that well but I have nice pic with about 237 clamps holding all the peices together while the glue sets. Its nothing that hasn't been seen her before but this topic is one that is continually arising here so another testimonial can't hurt. With all the bracing I think I could back the truck over these things and they'd be unscathed. I'm hoping to have them back up and running by the weekend or soon thereafter.