1979 Cornwall redo - what a find!

[longdrive03]

Buddy of mine found these at Savers (like Goodwill). He had just walked in store when Savers brought them out. $140 for the pair!!!!!!!!!!!!!! After thinking about it for a nanosecond he bought them complete with chicken wire installed in front of woofer from inside. Must have been in a bar or theater based on handles and bolt holes an chicken wire ala bar scene in Blues Brothers.

I am redoing these for him using curly walnut aircraft veneer. I'll replace the 2 and 4uf caps on the B network with some Sonicraft caps (he didn't want to spend more). I haven't picked them up yet but he says one K-77 tweeter might not work. These had a 1/4" pa jack in back and it may be lose.

Both woofers are K-33 (one square magnet and one round). The square magnet has a vented smaller dustcap than the other woofer. I'll test specs on woofers as part of redo. No grill frames so I'll build those. Plan on inserted solid walnut corner blocks and front trim.

These have the old upholstery stuff on walls. Anyone think I should keep it? Other than being old it is relatively good shape. I may add some cross and front to back bracing as well.

[billybob]

Sweet Find!

[Boxx]

Looks like a challenge... but it can be done...

[moray james]

Kapok is a very good short fiber damping material. you are not likely to find anything any better. Why don't you include some braces? I would add a single brace to the top sides and dual braces to the back. I would then tie all the braces together with one by two (3/4"x1 1/2"). I would also include horizontal braces above the woofer and over the woofer and tie those to the braces on the rear braces. Just my 2 cents. Best regards Moray James.

Edited April 21, 2014 by moray james

[muel]

Great Project! Have Fun!!

[longdrive03]

Thanks, should be fun. I removed the speakers and tested them - one bad K-77 but owner is replacing with Crites tweeters. Ripped out the old insulation and installed a small brace inside in the slot port to avoid the top of slot piece from vibrating as much. Removed screw in handles and eye bolts on top and will fill with dowels/water putty before veneering. I'll also put in some bracing. More later

[Schu]

redo them with a long shag rug matrerial all over the outside

[longdrive03]

Schu, that would be cheaper and faster! But then the question is what color - standard ugly red, pea green or Scooby Doo blue?? So many choices.

[longdrive03]

I tested the two different woofers (both K-33) from the Cornwalls and got different values. Number 1 (round magnet) has fs 37, qt .58, vas, 6.8cf, 93 db. Number 2 (square magnet) has fs 28, qt .31, vas 13.3cf, 96db (which is similar to my own K-33 woofers). Number two has the smaller dust cap with vent and must be a replacement probably from a different manufacturer.

[longdrive03]

Got a little work done. Trimmed the lip off the fronts (will reinstall solid walnut lip) and cleaned up the back edges with tablesaw. Panels are lumber core - not plywood. Backs and fronts are ply. Cut out the top and bottom corners to allow solid walnut roundovers to cover the veneer edges. Using curly walnut on these. I also plan on replacing mid horn with 8 x 12" internally mounted horn based on what customer wants to spend. Lots of loose veneer around the bottom ports. Will veneer the fronts as well.

[longdrive03]

The outer ply of the bottoms of both speakers was peeling so I stripped it off. Bottom is lumber core 3/4" (not plywood). I applied 1/8" plywood on bottoms clamped and glued to stablilize. The outer ply of the motor boards at vents has come look and I had to trim it out and them replace with new wood to get stable surface for veneer to stick to. Cutting out a larger midhorn using PE H812 8 x 12" horn so should allow greater dispersion. Hope to get to veneering soon with curly walnut after I add bracing in cabinets.

[longdrive03]

Update on progress. I got all the prep work done, cut the new larger mid horn hole, did some bracing on the inside, and veneered the top, sides and motor boards on both speakers. I'm applying solid cherry front edge and top corner trim now.

[Schu]

I have to be the one to admit... I don't know what is really going on with these???

Have you modified them?

[longdrive03]

Schu,

I have "modified" them by cutting a large mid horn hole and adding interior bracing on the sides, interior side of motor boards and front to back bracing. I also removed the outer layer of veneer on the bottom of the bottom (not plywood - wood core). I also cut 3/4 x 3/4" channels on the top and bottom from front to back where solid cherry will be inserted over the edges of the veneer. I installed corner 45 degree cleats to hold the corners in place after cutting the channels. I inserted a brace in the middle of the slot port. I also cut off the front lip to allow the new cherry lip to be installed over the now veneered motorboard. I installed magnets under the veneer on the motorboard to allow the new grill frames I will build to attach without ball and socket or Velcro. Filled in 1/2" whole for rca plug on the back and cut out new terminal hole towards the bottom. I will install Crites CT125 new tweeters and Crites "B" network cap redo kit. I'll also attach a built in riser on the bottom.

Other than that not much.

[CECAA850]

Do you have your mid horns yet? The hole looks like it would be for a Fastrac horn.

[Schu]

what are the wood planks along the top of the speaker for?

[ricktate]

I like how you think. I think the wood planks are for raised type trim or something, I did magnet idea on my Scalas. Rick

[djk]

"what are the wood planks along the top of the speaker for?"

It's called Lumbercore.

It was used in older finished Klipsch speakers.

[longdrive03]

Thanks guys.

Yes, DJK is correct. The sides and tops were not "plywood" in the normal sense. They are lumber core (or wood core) where the center of the board is solid wood planks joined together and then veneered on each side.

I cut out a 3/4" x 3/4" channel on each of the four corners from front to back to insert solid wood trim that will cover the edge of the veneer. It will look similar to the pics when finished with roundover on the edges.

I used the Dayton K812 horn from PE (270-304) on these cause I had then handy. I hated to do all this work and keep the small stock mid horn since I had the chance to use bigger horns. Here is link below to the horns. I've used them in other applications. They are bolt on so I made a wooden connect plate to bolt to the horn with a female screw in adapter.

Here is a pic from last night showing front trim applied (except for bottom which I'll do tonight). After that I attach the four top and bottom corner edges then flush trim, roundover, and sand.

https://www.parts-express.com/dayton-audio-h812-1-exponential-horn-100x60-2-bolt--270-304

[TasDom]

Thanks guys.

Yes, DJK is correct. The sides and tops were not "plywood" in the normal sense. They are lumber core (or wood core) where the center of the board is solid wood planks joined together and then veneered on each side.

I cut out a 3/4" x 3/4" channel on each of the four corners from front to back to insert solid wood trim that will cover the edge of the veneer. It will look similar to the pics when finished with roundover on the edges.

I used the Dayton K812 horn from PE (270-304) on these cause I had then handy. I hated to do all this work and keep the small stock mid horn since I had the chance to use bigger horns. Here is link below to the horns. I've used them in other applications. They are bolt on so I made a wooden connect plate to bolt to the horn with a female screw in adapter.

Here is a pic from last night showing front trim applied (except for bottom which I'll do tonight). After that I attach the four top and bottom corner edges then flush trim, roundover, and sand.

https://www.parts-express.com/dayton-audio-h812-1-exponential-horn-100x60-2-bolt--270-304

Very nice, I need a buddy like you!