Guest David H Posted September 10, 2009 Share Posted September 10, 2009 Drivers mounted. Quote Link to comment Share on other sites More sharing options...
Guest David H Posted September 10, 2009 Share Posted September 10, 2009 Closeup Quote Link to comment Share on other sites More sharing options...
Guest David H Posted September 10, 2009 Share Posted September 10, 2009 Because I do not yet have a home for these, I have chosen not to veneer them yet. For now I am coating with linseed oil for protection, actually the ply looks decent. Quote Link to comment Share on other sites More sharing options...
bliss53 Posted September 10, 2009 Share Posted September 10, 2009 Dave, Nice work. I like the removable motor board. What is your thinking on flaring the tweeter hole verses flush mounting? Quote Link to comment Share on other sites More sharing options...
Guest David H Posted September 10, 2009 Share Posted September 10, 2009 What is your thinking on flaring the tweeter hole verses flush mounting? Flush mounting that tweeter is a pain, I would have flush mounted the CT-125 because the motor is easily removable. Quote Link to comment Share on other sites More sharing options...
rll Posted September 10, 2009 Share Posted September 10, 2009 Dave, Good work. I like the flush-mounted horn. I hope by the time I'm ready to get my project off the ground you've decided to produce that version for sale. I also like your solution for the woofer, keeps it from protruding so far off the motorboard. Have you fired them up yet? What are you using for crossovers? Couple questions concerning your cabinet. 1. What did you use as the dimensions of your port holes? JWC's total ~50 square inches, which is also what Bob says. For the pair I built last winter, I used the Cornwall plans floating around that call for the holes to be 6 7/8" by 2 3/16", and the port shelf to be 9 1/2" deep and 2 3/8" above the bracing (or 3 1/8" above the floor). Using those dimensions, port hole area is 45.12 square inches. Am I missing something? 2. You increased your cabinet depth by 1", which I understand you did to offset the additional volume taken up by your horn and bracing, correct? Did you calculate this or is it an educated estimate? The difference in cabinet volume is ~.25 cubic feet, not taking into account the assorted parts, etc. How significant do you believe that is? Randy Quote Link to comment Share on other sites More sharing options...
jwc Posted September 10, 2009 Share Posted September 10, 2009 Gothover. I'm still a little confused. Is this the tractrix flare we came up with as a drop in replacement for the scala or the one for a Cornwall requiring baffle modification to install? Do you think it would be worth it to make the cabinets for folks unfinished and empty? Then leave the responsibility up to the buyer to install parts and "finish"? jc Quote Link to comment Share on other sites More sharing options...
kg4guy Posted September 10, 2009 Share Posted September 10, 2009 Making it in kit form so all they have to do is put the screws in and the glue on would be nice as shipping would be a fraction of what it would be to ship a assembled speaker box. Quote Link to comment Share on other sites More sharing options...
Guest David H Posted September 10, 2009 Share Posted September 10, 2009 Gothover. I'm still a little confused. Is this the tractrix flare we came up with as a drop in replacement for the scala or the one for a Cornwall requiring baffle modification to install? Do you think it would be worth it to make the cabinets for folks unfinished and empty? Then leave the responsibility up to the buyer to install parts and "finish"? jc I'm still a little confused. Is this the tractrix flare we came up with as a drop in replacement for the scala or the one for a Cornwall requiring baffle modification to install? Sorry JC, I guess I didnt clear that up. This is a Fastrac Cornwall modified for flush mount. But the Fastrac Lascala will fit in a stock Cornwall cabinet if I flush mount it. Do you think it would be worth it to make the cabinets for folks unfinished and empty? Then leave the responsibility up to the buyer to install parts and "finish"? JC, its just too much work, unless I had it CNC cut, and Bob Crites is already doing that I think. Quote Link to comment Share on other sites More sharing options...
bliss53 Posted September 10, 2009 Share Posted September 10, 2009 I guess I didnt clear that up. This is a Fastrac Cornwall modified for flush mount. But the Fastrac Lascala will fit in a stock Cornwall cabinet if I flush mount it. Does the la scala horn require a crossover change if it is used in the cornwall? Quote Link to comment Share on other sites More sharing options...
jwc Posted September 10, 2009 Share Posted September 10, 2009 Well, If the option is there to have made cabinets with Crites parts and a fastrac horn....that seems like a great hit. Just a thought.....I love the tractrix midhorns...that was the only bummer really with the cornwall in my book. You are right...the actual XO point wasn't as big of a difference. jc Quote Link to comment Share on other sites More sharing options...
Guest David H Posted September 10, 2009 Share Posted September 10, 2009 I guess I didnt clear that up. This is a Fastrac Cornwall modified for flush mount. But the Fastrac Lascala will fit in a stock Cornwall cabinet if I flush mount it. Does the la scala horn require a crossover change if it is used in the cornwall? No crossover change required. Quote Link to comment Share on other sites More sharing options...
Guest David H Posted September 11, 2009 Share Posted September 11, 2009 Dave, Good work. I like the flush-mounted horn. I hope by the time I'm ready to get my project off the ground you've decided to produce that version for sale. I also like your solution for the woofer, keeps it from protruding so far off the motorboard. Have you fired them up yet? What are you using for crossovers? Couple questions concerning your cabinet. 1. What did you use as the dimensions of your port holes? JWC's total ~50 square inches, which is also what Bob says. For the pair I built last winter, I used the Cornwall plans floating around that call for the holes to be 6 7/8" by 2 3/16", and the port shelf to be 9 1/2" deep and 2 3/8" above the bracing (or 3 1/8" above the floor). Using those dimensions, port hole area is 45.12 square inches. Am I missing something? 2. You increased your cabinet depth by 1", which I understand you did to offset the additional volume taken up by your horn and bracing, correct? Did you calculate this or is it an educated estimate? The difference in cabinet volume is ~.25 cubic feet, not taking into account the assorted parts, etc. How significant do you believe that is? Randy I will produce the flush mount horns as needed, I just need to find some good build techniques to clean it up a little more. I fired the Corn's up and they sound good, but I am waiting for a few parts for the new crossover. Currenty I am using an ALK universal crossover with the mid and tweeter dropped 3db. I am in the process of building the ALK Cornwall crossover which I prefer for it 600 Hz crossover point as discussed earlier in this thread. The Port and cabinet dimentions I got from JC and Bob Crites. The additional 1 inch cabinet depth is not overly important but decided to add it because I was scratch building and was an option. I have installed a few of these kits now, as have a few forum members, and have never heard any bass issues as a result, I dont think it is all that critical. Dave Harris Quote Link to comment Share on other sites More sharing options...
Guest David H Posted September 11, 2009 Share Posted September 11, 2009 I love the tractrix midhorns...that was the only bummer really with the cornwall in my book. I agree totally, I never cared for the Cornwalls til you an Bob built Cornscala's, from then I was hooked. Todays Cornwall update, up and running and installed the stands. Quote Link to comment Share on other sites More sharing options...
PrestonTom Posted September 11, 2009 Share Posted September 11, 2009 That looks like a fun project. Congratulations. Just as a point of clarification regarding "flush mounting". This term usually means that the driver is flush mounted to the front (not the back) of the baffle. Your picture shows that the tweeter is flush mounted to the rear. In your case there is now a cavity in front of the tweeter. In some cases, this can cause a cavity resonance and some additional diffraction problems when the wave hits the front edge of the baffle. I was not able to tell if you eased the edge with a round over bit or something. For those interested there is a very short discussion of this in H. Tremaine's "Audio Cyclopedia". -Tom Quote Link to comment Share on other sites More sharing options...
Guest David H Posted September 11, 2009 Share Posted September 11, 2009 That looks like a fun project. Congratulations. Just as a point of clarification regarding "flush mounting". This term usually means that the driver is flush mounted to the front (not the back) of the baffle. Your picture shows that the tweeter is flush mounted to the rear. In your case there is now a cavity in front of the tweeter. In some cases, this can cause a cavity resonance and some additional diffraction problems when the wave hits the front edge of the baffle. I was not able to tell if you eased the edge with a round over bit or something. For those interested there is a very short discussion of this in H. Tremaine's "Audio Cyclopedia". -Tom You are absolutely correct, however the reference to flush mount was directed at the mid horn only, not the tweeter. Quote Link to comment Share on other sites More sharing options...
kg4guy Posted September 11, 2009 Share Posted September 11, 2009 Dave another awesome job. I love the tractrix midhorns...that was the only bummer really with the cornwall in my book. I agree totally, I never cared for the Cornwalls til you an Bob built Cornscala's, from then I was hooked. Todays Cornwall update, up and running and installed the stands. Quote Link to comment Share on other sites More sharing options...
hklinker Posted September 11, 2009 Share Posted September 11, 2009 You guys are killing me! I can't wait till I get mine put together. Cabinets are done except the cutout for the new horns. Gothover, can you send me a PM with the dimensions so they will be ready to mount the new horns? I am going to start my post of the project tonight. Quote Link to comment Share on other sites More sharing options...
Guest David H Posted September 11, 2009 Share Posted September 11, 2009 I am sending you a cutting template with the horns, will make life much easier. Quote Link to comment Share on other sites More sharing options...
hklinker Posted September 11, 2009 Share Posted September 11, 2009 Outstanding! This will make things go much quicker! Quote Link to comment Share on other sites More sharing options...
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