rll Posted February 18, 2009 Share Posted February 18, 2009 this is my interpretation. Acknowledgements Thanks to Bob Crites for answering my questions and supplying the parts; to my neighbor Harry for allowing me the use of his power tools whilst he and his wife spend the winter in Arizona, without those this project would have been far more difficult; to my friend Gene for woodworking expertise and guidance (I have next to no woodworking skills, the last time I made anything was in junior high wood shop.); and finally to various forum members who have posted on the Cornscala concept. Background Last winter I rebuilt the crossovers in a pair of KG4s. At the same time I upgraded the tweeters with Bob's titanium diaphragms. They sounded better than ever. In the fall, Gene (he lurks here, not sure if he has ever posted), made the mistake of mentioning his plans to build a home theater in his basement. He had a budget, but did not know what to spend it on. I suggested Lascalas. Having never heard them or any Klipsch speaker aside from my KG4s, he decided to build some. He has excellent woodworking skills and a fully-equipped shop in his garage. Before he got started, a pair showed up locally on Craigslist, and I suggested he make an inquiry. Somehow he landed them, and for less than he could have built them. Turned out to be a pristine pair (I don't recall the vintage - '85 perhaps) owned by a musician clearing out some gear. He fell in love with them right away. At the same time, I was reminded of how good they were. He then scored another pair for the rears. I decided it was time to begin planning some Cornscalas. Cabinets Size considerations led me to settle on a standard Cornwall cabinet, using plans readily circulating on the forum. Nothing spectacular with the construction, but I'll supply details if anyone is interested. Used 3/4" MDF. No hardware, just biscuits, glue, and clamps. Blocking is simple 3/4" pine strips, glued and screwed. Baffle is glued and screwed. The picture (hopefully it loads) was taken a week and a half ago, shows them assembled for some listening prior to being torn apart for finishing. The sound was, in a word, sublime. David Gilmour never sounded so good, at least in this house. Before tearing them down for finishing, the last thing I listened to was Echoes on the Remember that Night bluray - incredible!! Despite their size, even the wife has given them her seal of approval. In a side-by-side with the KG4s, I wasn't sure she'd hear the difference, but she did. She was initially skeptical, but now she's anxious to have them finished, in place, and making music. More details to follow.... Quote Link to comment Share on other sites More sharing options...
CIGARBUM Posted February 18, 2009 Share Posted February 18, 2009 Good for you. I too am building a pair of Cornscala's, see Cornscala's Again. I don't hava a lot of skills when it comes to building speakers, this is my first attempt. I totally agree with the comment that if it had not been for all the good folks on the forum I wouldn't know where to start. Thanks again to all of you, I really appreciate all your help. Sure wish I had some neighbors, living here in the sticks don't help. Cigarbum Quote Link to comment Share on other sites More sharing options...
soundbound Posted February 18, 2009 Share Posted February 18, 2009 Nice. Quote Link to comment Share on other sites More sharing options...
rll Posted February 18, 2009 Author Share Posted February 18, 2009 Good for you. I too am building a pair of Cornscala's, see Cornscala's Again. I don't hava a lot of skills when it comes to building speakers, this is my first attempt. I totally agree with the comment that if it had not been for all the good folks on the forum I wouldn't know where to start. Thanks again to all of you, I really appreciate all your help. Sure wish I had some neighbors, living here in the sticks don't help. Cigarbum Cigarbum, I've been following your progress. I'd been planning to post something for several weeks weeks. When your post first appeared I thought I'd better get off my rear and do it. I'd never before so much as considered building a speaker, but the thought of a Cornwall with a better midrange lodged itself in my brain and wouldn't let go. First cut wood around Thanksgiving, planned to take my time with the whole process. Reached a point where I had to have horns and drivers in order to cut holes in the baffle, and everything accelerated from there. Looks as thought you've taken the mid and tweeter to a different level. I never spoke with anyone other than Bob, but pored through countless posts on the forum to steal ideas. Randy Quote Link to comment Share on other sites More sharing options...
rll Posted February 18, 2009 Author Share Posted February 18, 2009 Drivers, All drivers, horns, and crossover parts were acquired from Bob and Michael Crites. Tweeter is their CT125, woofer their CW1526C. Mid-range driver is the Atlas PD-5VH. Mid-range horn is MG Electronics' PH800 (supplied by Bob). Baffle is permanently attached to the cabinet and I plan to do the same with the rear cover. That meant front-mounting everything, which in turn meant thinking through how to do it. My research told me t-nuts would not be a good choice for MDF, but I stumbled across hurricane nuts at Parts Express. They're cheap, so I ordered a bag to test on a piece of scrap. Seated them by drawing them in with a screw and washer. They work quite well, bite in with no movement, and stay put if a screw is backed out. Crossover is a modified Type B, with 500 and 4,500 crossover points. Randy Quote Link to comment Share on other sites More sharing options...
CIGARBUM Posted February 18, 2009 Share Posted February 18, 2009 It's a lot of work, but I sure enjoy it. I may have some other pictures later today. It looks that you've got some real good equipment and the build looks great. The trachorns are flush mount which is no problem, but the tweeter I think has to be recessed about 1/8", not sure how to do this, I don't have a whole lot of fancy equipment, whdere there is a will there is a way. Later CB Quote Link to comment Share on other sites More sharing options...
rll Posted February 18, 2009 Author Share Posted February 18, 2009 It's a lot of work, but I sure enjoy it. I may have some other pictures later today. It looks that you've got some real good equipment and the build looks great. The trachorns are flush mount which is no problem, but the tweeter I think has to be recessed about 1/8", not sure how to do this, I don't have a whole lot of fancy equipment, whdere there is a will there is a way. Later CB Cigarbum, It is a lot of work, but it is a lot of fun. I ride a bit, but if it's windy (and it can blow here at times) or snowy, I'm stuck in the basement on a trainer. The wife says I haven't been as cranky this winter. I suspect it's because I've had this project to work on. It does seem to have helped the winter pass. As for recessing your tweeter. If I understand what you are saying, here's how I did it. First I located the horn on the correct spot on the baffle. Then I scribed the outside edge of the horn on the baffle. Using the neighbor's router, a 5/8" straight bit set to a depth of 1/8", and a straight edge as a guide, I carefully cut that lip into the baffle. Once I had it properly sized, I measured the width of the flange on each side of the horn, and transferred that dimension to the baffle. I replaced the bit with a 1/4" straight bit and cut out the hole. Actually I practiced my technique on a scrap first. It all went as planned and came out perfectly. I have a question for you concerning those stiffeners on the sides and back. The Cornwall III uses braces between the motorboard and rear cover to reduce resonance. I haven't committed to incorporating those into mine yet, but may. Just wondering if your stiffeners accomplish the same thing, or what opinion you or anyone else may have on them. Keep up the good work. Randy Quote Link to comment Share on other sites More sharing options...
CIGARBUM Posted February 18, 2009 Share Posted February 18, 2009 The stiffeners, well, I really didn't like the ones the other guys did, it looked like an after thought and ifdepending how tight they forced the brace in place, they are inducing a very concentrated load over just a couple of square inches. If I understand the therory of the wall resonance, is tio redduce the frequency of the wood (could be wrong), but anyway, did some calulations and seens to work out, and they are hid by the fussy stuff on the wall of the box. The recessing would only be 1/8" for the tweeter, I'll work something out. Just don't have a whole bunch of fancy tools. Quote Link to comment Share on other sites More sharing options...
Marvel Posted February 18, 2009 Share Posted February 18, 2009 I love the work you guys are doing. I mentioned this in another thread, but will do so again. The cabinet maker/carpenter at the college where I work, often uses either t-nuts or hurricane nuts on projects. Often, they are inaccessible once everything is together. To keep them seated, he will glue or glue and screw a small block of wood over the nut to provide additional insurance that it won't come out. It needs a hole in it, too. You could use a small scrap of 1/2 inch ply. I think the pic may explain more than my words. It keeps goofy guys like me from coming along and pushing out the nut. [:$] Quote Link to comment Share on other sites More sharing options...
Daddy Dee Posted February 18, 2009 Share Posted February 18, 2009 beauty, eh! What are you planning for finishing the cabs? Quote Link to comment Share on other sites More sharing options...
rll Posted February 20, 2009 Author Share Posted February 20, 2009 I love the work you guys are doing. I mentioned this in another thread, but will do so again. The cabinet maker/carpenter at the college where I work, often uses either t-nuts or hurricane nuts on projects. Often, they are inaccessible once everything is together. To keep them seated, he will glue or glue and screw a small block of wood over the nut to provide additional insurance that it won't come out. It needs a hole in it, too. You could use a small scrap of 1/2 inch ply. I think the pic may explain more than my words. It keeps goofy guys like me from coming along and pushing out the nut. Granted, my experience with hurricane nuts up to this time is, well, zero, but they sure seem to bite in. One would have to almost be trying to force them back out. That said, I hear you. I am planning to pull them all, add a drop or two of superglue to each and reinsert, just haven't gotten around to it. That ought to take care of them. Randy Quote Link to comment Share on other sites More sharing options...
rll Posted February 20, 2009 Author Share Posted February 20, 2009 beauty, eh! What are you planning for finishing the cabs? Daddy Dee, Thanks. I went with MDF rather than cabinet-grade plywood so that if I made a mistake it would not be an expensive one. I'm not quite ready to tackle veneering, maybe at a later date. The room these will be going in already has quite a few different types of wood with a variety of finishes. Just a wierd thing with me, but at a certain point so many finishes gets too busy for me. And last, the cabinets have one small construction flaw that most people would find indetectable (attributed largely to excess clamping pressure). So, with all those considerations, I decided to roll on a satin black latex paint. First, I rolled on two coats of oil-based primer/sealer, following each coat with a light sanding of 220 grit sandpaper to get rid of any high spots. Rolled on three coats of the latex, following the first two with 220 again, and the third with 320. The fourth (it went on last night) and fifth coats are applied with a sponge brush, which is then dragged the length of each piece to create a poor-man's woodgrain effect. It's not perfect, but for this pair it does what I'm looking to achieve. Last will be two coats of wipe-on polyurethane for protection, the first followed by a very light 320 grit sanding. I'll get a handfull of pictures up this weekend. Quote Link to comment Share on other sites More sharing options...
rll Posted February 23, 2009 Author Share Posted February 23, 2009 Cabinets are done, finish is on. Later on, I'll backfill on the fabrication process and lessons learned. Don't have many photos of the early stages, but a description may suffice. For now, let's build some speakers! Quote Link to comment Share on other sites More sharing options...
rll Posted February 23, 2009 Author Share Posted February 23, 2009 First, the crossovers. Modified Type B, 500 and 4,500 hz crossover points. MDF scraps are adequate for this application. Quote Link to comment Share on other sites More sharing options...
rll Posted February 23, 2009 Author Share Posted February 23, 2009 Best to lay them on their sides. Note hurricane nuts used to attach PH-800 and woofer. Quote Link to comment Share on other sites More sharing options...
rll Posted February 23, 2009 Author Share Posted February 23, 2009 Next up, the woofers and horns. Easier done with cabinets on their back. First the woofers. Quote Link to comment Share on other sites More sharing options...
rll Posted February 23, 2009 Author Share Posted February 23, 2009 ....then the mid and tweeter. (Forgot to take shot of the tweeter) Quote Link to comment Share on other sites More sharing options...
rll Posted February 23, 2009 Author Share Posted February 23, 2009 Now we screw in the drivers. Don't forget the gaskets. Quote Link to comment Share on other sites More sharing options...
rll Posted February 23, 2009 Author Share Posted February 23, 2009 All drivers attached. Quote Link to comment Share on other sites More sharing options...
rll Posted February 23, 2009 Author Share Posted February 23, 2009 Next up, connect drivers to the crossover terminal strip. Quote Link to comment Share on other sites More sharing options...
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