Colin Posted November 17, 2004 Share Posted November 17, 2004 the talk of the Corn=scalla has me wondering, how hard would it be to make the 15" wooder section of the Cornwll to add to Khorn mid and upper horns? Would JBL bass bin be a less expenisve or better match? Quote Link to comment Share on other sites More sharing options...
hwatkins Posted November 17, 2004 Share Posted November 17, 2004 Good question Colin - my first inclination would be to use a JBL bass bin - The plans are readily available and I think it is a good match for the rest of the the cornwall horns. My current building project is a JBL bin with the horns mounted on top in a separate surround. I like the sound of the JBL and find it at least comparable. The bin also frees up the creativity in design of the overall speaker. Quote Link to comment Share on other sites More sharing options...
Tom Mobley Posted November 17, 2004 Share Posted November 17, 2004 Colin, Did you look thru Bob Crites thread titled "Let's build a driver test box" in this section? It's got quite a lot of detail around the questions you're asking, unless I'm misunderstanding what you're asking. Quote Link to comment Share on other sites More sharing options...
mike stehr Posted November 17, 2004 Share Posted November 17, 2004 It's a rather mediocre looking 10 incher, 2 inch voice coil, reasonably sized magnet I suppose. But in a 3 foot internal volume cabinet ported to around 36 Hz with a low watt tube amp they can boogie. They have have a real nice lower midbass and midrange tone to them, to me anyways... They can get down low as well. They work well in a two-way kind of set-up, with a helper tweeter. It's a bastard speaker for sure..... Quote Link to comment Share on other sites More sharing options...
colterphoto1 Posted November 26, 2004 Share Posted November 26, 2004 Or there's always the old PA standard EV-TL series. Available with plans from EV. For the EVM-15B, it's a big about as wide as Cornwall, 1/2 as tall, slightly deeper. Also available for 12" and 18" woofers. 18"TL bin is about as big as a LaScala cabinet. Michael Quote Link to comment Share on other sites More sharing options...
J.4knee Posted November 29, 2004 Share Posted November 29, 2004 Am I missing something here, is this not what Bob Crites just did? I beleive Bob even indicated his cabinet maker can do it for about $100/cabinet. Or am I just totally missing the intent of ths post? Quote Link to comment Share on other sites More sharing options...
D-MAN Posted November 29, 2004 Share Posted November 29, 2004 I think Bob's would be an easier build, UNLESS you happen across an old pair of JBL's. Starting from scratch, I'd go with the Corn-Scala... DM Quote Link to comment Share on other sites More sharing options...
jwc Posted November 29, 2004 Share Posted November 29, 2004 What would be the crossover options of the Cornscala. A cornwall-like or a scala-like. Quote Link to comment Share on other sites More sharing options...
BEC Posted November 29, 2004 Share Posted November 29, 2004 You can start with a type B crossover and just change one cap to cross the midrange over at 400 hz instead of 600 hz. Bob Crites Quote Link to comment Share on other sites More sharing options...
jwc Posted November 30, 2004 Share Posted November 30, 2004 Hey Bob, Thanks for the input. The reason I asked is because I have invisioned such a project as the Cornscala. I've seen your posts. Question, Is there a way to keep the same cubic volume of the bass bin but make it taller and skinnier? I would like to have a speaker taller than the cornwall or the scala and make the width just about the width of the mid on the scala. Would that change the "tuning" of the 15" woofer to be unsatisfactory or would there need to be a crossover change? jc Quote Link to comment Share on other sites More sharing options...
BEC Posted November 30, 2004 Share Posted November 30, 2004 ---------------- On 11/30/2004 9:41:31 AM jwcullison wrote: Hey Bob, Thanks for the input. The reason I asked is because I have invisioned such a project as the Cornscala. I've seen your posts. Question, Is there a way to keep the same cubic volume of the bass bin but make it taller and skinnier? I would like to have a speaker taller than the cornwall or the scala and make the width just about the width of the mid on the scala. Would that change the "tuning" of the 15" woofer to be unsatisfactory or would there need to be a crossover change? jc ---------------- jc, The volume of the box and the area of the ports are important to keep the Bass output at about the same as a Cornwall. The width of the motor board could decrease by a couple of inches and still accomodate the width of the K-401. The depth is really dictated by the length of the K-401 horn and its driver. That is about 24 inches when it is mounted on the back of a 3/4 inch motor board. Of course the bass bin could be less than that depth, but the horn would still place the front of the cabinet 24 inches from a wall. Bob Crites Quote Link to comment Share on other sites More sharing options...
jwc Posted November 30, 2004 Share Posted November 30, 2004 Exactly Yes the Mid horn will dictate the minimum width and depth. I'm not concerned about the depth. If it had to be deeper than the mid horn, thats , ok. I will try and send you a diagram of such a cabinet that I have in mind. I will try to keep the cabinet's internal volume for the bass bin the same. Please don't laugh, it might be crude. Again, tell me what the internal volume of the bass bin is? jc Quote Link to comment Share on other sites More sharing options...
colterphoto1 Posted November 30, 2004 Share Posted November 30, 2004 JC, Just doing some reading and saw your post. I've got some experience with cabinet design and would offer this to you. The ratio of the sides of the Mighty Cornwall cabinet as engineered by Klipsch is (okay externally, but ratios are still similar) 35.75:25.5:15.5 inches, which equates to 1:.71:.43 please note that none of these dimensions is similar and the ratios are not halves or quarters. They seem to be very random numbers that have nothing to do with one another. Good. It's the same basic principle as the dimensions of the listening room. One would not design a HT room that was 16x16x8 feet. Reason, it causes an extreme build up of standing waves, or the emphasis of some frequencies over others. Try to keep this in mind when designing your cabinets. So long as you keep the overall INTERIOR volume close to the same as your original Cornwall, the PORT VOLUME (take into account the shelf, which gives the port depth) should also be identical. This would greatly simplify your cabinet building if you can manage it. Otherwise, if you change the cabinet volume by a significant amount (I dunno, maybe 5-10%) you would have to recalculate the port volume. Also remember to add the dampening material to one of each pair of parallel cabinet walls, generally top, back, and one side. This also helps break of standing waves. I'm sure there are other more advanced speaker builders out there and numerous books on the subject. Just wanted you to get thinking correctly about cabinets before you let aesthtics rule entirely. There are sound (pun intended) acoustical principles that must be applied. Hope this helps- didn't mean to confuse. Michael Quote Link to comment Share on other sites More sharing options...
colterphoto1 Posted November 30, 2004 Share Posted November 30, 2004 Ok JC, I was feeling a bit adventerous, perhaps the spirit of Bob Crites or William McDermott was at play here, but I did some preliminary calculations for you. THESE ARE ROUGH. Based on your wants list, this may be a pretty bizarre cabinet indeed. Starting with Cornwalls' stated exterior measurements, stated above, and subtracting 1.5 inches each dimension for thickness of two walls, interior volume is approx 80 in3. (note to experts, since components are roughly the same in both instances, I am not subtracting the volume for 15" cone and mid horn, nor for the port volume)in order to simplify these rough calculations. #1 In order to avoid redesigning the port volume, a cabinet could be (these are rough exterior dimensions) 38 height, 24 deep (for K400) and would therefore be only 16 wide to end up with roughly 82 in3 interior volume. This would be a little goofy looking, the depth would be exactly 1.5 x the width (not a good thing) and the woofer would barely mount on the motor board, to say nothing of the K400 minimum width (help out here Bob)The face of this cabinet would be like a Chorus II slimmer by 1/5 inches but twice as deep. Kinda odd. #2 Here is what might be possible...again outside dimensions. 31high, 19 wide, 24 deep. You could build a riser for the optimum listening height. The ratios work out well 1:.61:.77 and the components would fit better. This would give about 80.5in3 interior volume, same as original Cornwall. Only 4" shorter than LaScala, just as deep and a little narrower. I've not drawn it up to see what it would look like. #3 So... If #1 or #2 don't appeal, since the criterior for squeezing these components into a single box the same volume as Cornwall, but taller cannot be met, a re-engineering of the port volume would be in order. Not terribly complex, but I cant do it without woofer values and charts. Not off the top of my head anyway. Again, it's a fun little game, hope to not mislead or confuse. Michael Quote Link to comment Share on other sites More sharing options...
BEC Posted November 30, 2004 Share Posted November 30, 2004 The internal volume of a real Cornwall (vertical) that I have is a bit less than 6 cubic feet. Some of this volume is occupied by the 3 drivers and the shelf. That amount would have to be subtracted to get down to real air volume which is what is important when considering performance of the bass driver. Bob Crites Quote Link to comment Share on other sites More sharing options...
Daddy Dee Posted November 30, 2004 Share Posted November 30, 2004 This CornScala has got great possibilities to be good looking as well as good sounding. The length of the K400 at 24 inches is pretty deep and designing around it is a challenge. Does anyone know the dimensions of the Belle midhorn? Is it the K500 or K530? What is the depth with driver? What is the width of the horn flare at the front? Also, does the AB crossover cross at 500hz? I'm assuming that crossing the K55 at 400hz requuires the K400 in order to hear it. I wonder how far the K500 could be pushed below it's rating to be more cabinet friendly and sound better, too. One more odd question. I've been trying to imagine somehow sealing the rear end of a K400 and K55 sticking through the back of a cornwall cab. It would certainly look strange, from the back, but haven't been able to think of anything that would work anyway. Quote Link to comment Share on other sites More sharing options...
Frzninvt Posted November 30, 2004 Share Posted November 30, 2004 The Belle is 18.75" deep and the back of the K-55V is close to the back of the cabinet but the K-501 would certainly make the cabinet narrower by close to half a foot! Quote Link to comment Share on other sites More sharing options...
colterphoto1 Posted November 30, 2004 Share Posted November 30, 2004 oops, my bad Bob, hxwxd=vol in in3 that/12/12/12 is ft3, I fergot the last /12 so Corn is approx 6.6 interior (again NOT taking out for driver vol or port vol) #1 example is 6.9 #2 example is 6.7 so those are close to original cabinet. I'll approximate another one using the K501 Belle horn, It'll probably give a nice appearing, taller cabinet if we don't have to go so deep. Michael Quote Link to comment Share on other sites More sharing options...
colterphoto1 Posted November 30, 2004 Share Posted November 30, 2004 Ok, how bout the BelleCorn It's 35 tall (same as LS, .75 shorter than Cornwall) it's 21.5 wide ( 2 narrower than LS, 4 narrower than Corn) it's 19 deep (same as Belle, same as LS, 3.5 deeper than Corn. ratios work out to 1:.61:.54 with w:d- 1:1.31, so looks pretty good in not assisting any standing wave nodes. At 6.78 ft3 interior approx, its within 2% based on my rough calculation, so port volume would be about same as standard Cornwall. Hey People, THIS COULD WORK and could also be the answer for those of us wanting to build our own Vertical Cornwall for Center HT use!!wwwoooohhhoooo Michael Quote Link to comment Share on other sites More sharing options...
Daddy Dee Posted November 30, 2004 Share Posted November 30, 2004 Michael, Thanks for working that out. Quote Link to comment Share on other sites More sharing options...
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