Guest David H Posted September 7, 2009 Share Posted September 7, 2009 It has been a while since I have had time to do any building, and I have accumulated a few parts along the way. This is a standard scratch built Cornwall, except this Cornwall is One inch deeper than a standard to accomodate my 400hz Fastrac lens and the added internal bracing, which I neglected to add before installing the badding. This Cornwall will be using O/E K-33, K-52H, and a pair of old K-77's once my new diaphrams arrive. Quote Link to comment Share on other sites More sharing options...
Guest David H Posted September 7, 2009 Share Posted September 7, 2009 Badding added, pic 2 Quote Link to comment Share on other sites More sharing options...
Guest David H Posted September 7, 2009 Share Posted September 7, 2009 Flush mount Fastrac Cornwall Lens. Quote Link to comment Share on other sites More sharing options...
Guest David H Posted September 7, 2009 Share Posted September 7, 2009 Here is a shot of the Standard Fastrac Cornwall lens fresh from the paint booth. Quote Link to comment Share on other sites More sharing options...
Guest David H Posted September 7, 2009 Share Posted September 7, 2009 One more shot showing the added depth. Once again, I made the fronts removeable so I can properly brace the back and sides, the motor board is stiffened by its drivers, and doublers. Quote Link to comment Share on other sites More sharing options...
jwc Posted September 7, 2009 Share Posted September 7, 2009 Gothover.... Those are the midhorns that are drop in for the K401/400....right? So you are making a "mod" that allows them to be a tight seal with the baffle on the corn? I'm loving this.......That would make for a nice "kit". jc Quote Link to comment Share on other sites More sharing options...
Guest David H Posted September 8, 2009 Share Posted September 8, 2009 Yes JC. The K-400 drop in replacement replacement is 3/4 inch deeper than the Cornwall Horn, therefore if it is flush mounted it will work fine in a Cornwall. However I still prefer the sound of the Cornwall crossed at 600 Hz therefore either horn will work nicely. Using an active crossover I came to the realization that the K-33 woofer does a far better job at 600hz than the K-55 or K-52H does at 400hz. JC I believe it was you who suggested I try this and you were correct. There is no need to configure a Cornwall with a lower crossover frequency, simply update the horn to a Tractrix design, and if so desired install a better crossover. Dave Harris Quote Link to comment Share on other sites More sharing options...
hklinker Posted September 8, 2009 Share Posted September 8, 2009 Gothover, Is this the Fastrac that fits in the standard Cornwall like your doing for me, or the deeper ones? Herb Quote Link to comment Share on other sites More sharing options...
Guest David H Posted September 8, 2009 Share Posted September 8, 2009 Another pic of the flush mount lens. I believe Greg928gts did a similar mount for his 2" Super Cornwall project. Quote Link to comment Share on other sites More sharing options...
Guest David H Posted September 8, 2009 Share Posted September 8, 2009 Herb, the Black ones that just came out of the paint booth are your horns. The newer flushmounts I did are a first for me, but are not going to be audibly different from the ones I am sending you. I still have to make your cutting Jig, and install the K-55 adapters. The cutting jig will be ready wednesday. Dave. Quote Link to comment Share on other sites More sharing options...
bliss53 Posted September 8, 2009 Share Posted September 8, 2009 I remember discussing the flush mount. I am glad you tried it. This may be my choice for the cornwalls I just got from jtnfoley. These also have K57 drivers that will require adapters. A friend has heard my last ones with new cherry veneer, your horns and crossovers and wants to buy them. Can not sell them until I replace them. The more time I spend listening the more I enjoy them. My wife stills asks me to turn them down, but I am not as bothered because the horn sounds so much better than stock at lower volume levels. Great work. Quote Link to comment Share on other sites More sharing options...
greg928gts Posted September 8, 2009 Share Posted September 8, 2009 Another pic of the flush mount lens. I believe Greg928gts did a similar mount for his 2" Super Cornwall project. Yup. It's easy to mount and seal. It can also be mounted to a Cornwall II by using bolts instead of screws. Mine don't sound good crossed at 600hz. At least not with the crossovers I built. I'm going to try a lower crossover point, along with a few other things when I get the time. Greg Quote Link to comment Share on other sites More sharing options...
Guest David H Posted September 8, 2009 Share Posted September 8, 2009 Actually Bliss, it was your Cornwall Project that inspired the flush mount idea, however it has not yet been tested, and I am not sure it is ready for general use. The concern I have using this horn in a standard Cornwall is the loading of the removable back cover. However I think this can be addressed by by installing a rear brace to support the horn and load the back pannel. The other issue I have is the the K-400 drop in replacement horn is considerably larger than my Cornwall horn, and I think it might be getting to the point where additional cabinet volume would be warranted. I am sure if you sell your Cornwalls, your next set will be even better. Let me know if you need anything. The Cornwalls I am building here are strictly a labor of love, I have absolutely no use for them just enjoy building. Dave. Quote Link to comment Share on other sites More sharing options...
hklinker Posted September 8, 2009 Share Posted September 8, 2009 Dave, So these are mounted from behind like the original squawkers? Herb Quote Link to comment Share on other sites More sharing options...
bliss53 Posted September 8, 2009 Share Posted September 8, 2009 Dave, With my home made adapter there was some clearance and with the K52 adapters there was no clearance. I could not hear the difference between loading and not loading. The horns in the la scala and the khorn do not have any pressure other than a support arm. What is the theory on loading? Would a compressable material (rubber) mounted to the back provide the pressure? Or maybe a cross member in the cabinet attached to the horn? Quote Link to comment Share on other sites More sharing options...
bliss53 Posted September 8, 2009 Share Posted September 8, 2009 Herb, Nice turntable in the avatar. Quote Link to comment Share on other sites More sharing options...
Guest David H Posted September 8, 2009 Share Posted September 8, 2009 Dave, So these are mounted from behind like the original squawkers? Herb Yes, they are rear mounted like the originals. Quote Link to comment Share on other sites More sharing options...
Guest David H Posted September 8, 2009 Share Posted September 8, 2009 Dave, With my home made adapter there was some clearance and with the K52 adapters there was no clearance. I could not hear the difference between loading and not loading. The horns in the la scala and the khorn do not have any pressure other than a support arm. What is the theory on loading? The loading is to keep the back pannel from sounding off. What I am referring to is cabinet bracing, in the Cornwall the rear of the horn/motor assembly contacts the rear of the Cornwall bracing the rear pannel. Nothing to do with the horns. Quote Link to comment Share on other sites More sharing options...
Guest David H Posted September 10, 2009 Share Posted September 10, 2009 Horn flush mounted to motor board. Quote Link to comment Share on other sites More sharing options...
Guest David H Posted September 10, 2009 Share Posted September 10, 2009 Woofer Doubler Quote Link to comment Share on other sites More sharing options...
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