volvotreter Posted August 31, 2000 Share Posted August 31, 2000 Hi there, I took a close look on the plans for Klipsch La Scala floating on the net. Basically they are all the same but they all differ in a certain point. The distance indicated in the ? 'drawing' with <-> varies from 2 1/2" over 2 3/4" to 3" in my plans: +----------\ /----------+ / ? V xxxxxx / / <-> +-----------+ y / / / chamber / y / / / with 15" / y / / / bass / y / horizontal / / driver / / cross section / / / / / / / / / / / / / / / I think 3" is right, because everything below 3" would mean the area of the horn decreases at the transition x to y in my 'drawing'. So, could you please take an inch rule and give me the right measurement? Or just mail me your plans if you got some Thanks in advance! Erik Quote Link to comment Share on other sites More sharing options...
Tony Reed Posted August 31, 2000 Share Posted August 31, 2000 Overall width of the LaScala's is 23.75 inches. The construction is of .75 birch. The inside of the woofer chamber is 15.25 inches. (where the 15 inch woofer is mounted) The inner parallel chamber walls are .75 inches. (1 on each side/total of 1.5) The outer cabinet walls are another .75 inches. (1 on each side/total of 1.5) That's a total of 18.25 inches. (23.75 - 18.25 = 5.5) The remaining 5.5 inches divided by 2 is 2.75 inches. (I hope my math was right!) I have factory LaScala's, which is what I measured for my drawings. Not being totally satisfied with that, I measured a friend's pair. Same thing. The measurement on both pair was 2 3/4 inches. This seems somewhat odd to me as well but, that's what it is. Just to easy your mind, find a factory pair and measure them. Tony Quote Link to comment Share on other sites More sharing options...
Stig Posted September 1, 2000 Share Posted September 1, 2000 Volvotreter, It seems you also are wondering about that mystery 2.5in.,2.75in. or 3in. area. The 2.75in. seems to be correct. Both sets of plans I have seen show a 60 degree angle for the inside of the air chamber. With the 2.75in. width it matches but with the 2.5in. it does not. There is a bigger question however, one I posted on 8-28-2000 in "UPdating Older Speakers". The "area" in question, which is I beleive 2.75wide by 22.25in. high (inside heigth of horn) stays parallel for 7.5in. and does not expand. This "area" comes after the first flare exiting the throat and before the final flare. The question is what is this "area" for if it does not expand. I've had a couple of bites at an answer (thanks for the reply guys) but nothing concrete. Maybe one of the "Moderators" will explain the mystery. I would really enjoy an answer from "Mr. Klipsch" on this one. I hope I didn't confuse things. Stig Also thanks to Tony for the measurements Quote Link to comment Share on other sites More sharing options...
volvotreter Posted September 1, 2000 Author Share Posted September 1, 2000 Stig, I think it's even worse. Just before the 90° turn (at the edge of he doghouse) there is a horn area of 3"x23". After the turn, the area is reduced to 2.75"x23" and stays like that for the next 7.5". And I allway thaugt that the area of a horn should allways increase??!! Quote Link to comment Share on other sites More sharing options...
volvotreter Posted September 1, 2000 Author Share Posted September 1, 2000 just an illustration to my comments above! Quote Link to comment Share on other sites More sharing options...
Klewless Posted September 1, 2000 Share Posted September 1, 2000 More on this, The LaScala is not a perfect horn. It is two wedges which taken overall approximate the exponential flare. A "perfect" horn does expand for every increment in length. I have not opened up my LaScalas to see but could "guess" that the straight non-expanding section could do one or both of the following: 1. Make additional clearance room inside the chamber for the 15" driver". and/or 2. Increase the volume of the chamber at the expense of flare on the horn. Maybe it's just easier to manufacture them the way they do it. ------------------ John P St Paul, MN Quote Link to comment Share on other sites More sharing options...
Stig Posted September 1, 2000 Share Posted September 1, 2000 Volvotreter, Now I have seen three different sets of plans showing different dimensions in this parallel area. One with 2.5in. by 23in., another with 2.75in. by 22.25in. and the last with 3in. by 23in. Is there "ANYBODY" on this BB that knows if the La Scala was ever made by Klipsch using different internal dimensions for the horn? Where is the Klipsch historian when you need him? How 'bout if everybody that owns La Scala's gets a tape measure and posts their internal horn dimensions. That would put it all on the table. Ain't this this horn stuff fun. Stig Quote Link to comment Share on other sites More sharing options...
Stig Posted September 2, 2000 Share Posted September 2, 2000 Volvotreter, OOOOPS, Foget that 3in.x23in.- thats the width of the first flare. I looked at it backwards on your diagram but that still leaves two. Stig Quote Link to comment Share on other sites More sharing options...
djk Posted September 3, 2000 Share Posted September 3, 2000 quote: Originally posted by Stig: Volvotreter, Now I have seen three different sets of plans showing different dimensions in this parallel area. One with 2.5in. by 23in., another with 2.75in. by 22.25in. and the last with 3in. by 23in. Is there "ANYBODY" on this BB that knows if the La Scala was ever made by Klipsch using different internal dimensions for the horn? Where is the Klipsch historian when you need him? How 'bout if everybody that owns La Scala's gets a tape measure and posts their internal horn dimensions. That would put it all on the table. Ain't this this horn stuff fun. Stig The answer is really quite simple.The LaScala was originally made from 1/2" plywood so the dimension in question was 3".When the price was lowered in the 70's the expensive all hardwood,no void,18 ply per inch 12mm baltic birch was changed to ordinary 3/4" 7 core softwood plywood with birch faces.The external dimensions were unchanged so it got narrower inside. Quote Link to comment Share on other sites More sharing options...
Stig Posted September 7, 2000 Share Posted September 7, 2000 quote: Originally posted by djk: The answer is really quite simple.The LaScala was originally made from 1/2" plywood so the dimension in question was 3".When the price was lowered in the 70's the expensive all hardwood,no void,18 ply per inch 12mm baltic birch was changed to ordinary 3/4" 7 core softwood plywood with birch faces.The external dimensions were unchanged so it got narrower inside. djk, Sorry for my late reply but I've been out looking for that " all hardwood, no void, 18 ply per inch 12mm baltic birch". In your post you say it got narrower inside. A change from 1/2in. to 3/4in. would have changed "ALL" internal dimensions. I was under the assumption that horns had to be built precisely. From what I'm reading all over the BB it seems that if I build a pair of horns and I'm off a 1/4in. here a 1/2in. there that it wont matter because they are only approximations of a certain flare rate. If that is true why is the Khorn so intricate and so *********** hard to build? Ain't this horn stuff fun. Thanks, Stig Quote Link to comment Share on other sites More sharing options...
djk Posted September 7, 2000 Share Posted September 7, 2000 quote: Originally posted by Stig: djk, Sorry for my late reply but I've been out looking for that " all hardwood, no void, 18 ply per inch 12mm baltic birch". In your post you say it got narrower inside. A change from 1/2in. to 3/4in. would have changed "ALL" internal dimensions. I was under the assumption that horns had to be built precisely. From what I'm reading all over the BB it seems that if I build a pair of horns and I'm off a 1/4in. here a 1/2in. there that it wont matter because they are only approximations of a certain flare rate. If that is true why is the Khorn so intricate and so *********** hard to build? Ain't this horn stuff fun. Thanks, Stig Baltic birch is usually delivered by pool trucks from(for where I live)out of state distributors."B" faces 5'x5' only.They have a truck that makes a route all the small yards and cabinet shops every two weeks.Call a local cabinet shop and see where he gets his from.Appleply is an American product with poplar and alderwood cores and maple faces,one inch has a total of twenty plies."A" faces 4'x8'.Finnform is used by people that pour concrete,similar to Baltic birch but not sanded.Many sizes available.I made 24 LaScala sized bass horns in 1978.I added corner reflectors and increased the 'shrunk' dimension back to 3" and changed the internal doghouse dimension to 15 3/4" to accomodate non-Klipsch woofers.The higher in frequency the horn operates and the closer to the throat you are the more important the dimensional accuracy is.After making eight pieces I left out the corner reflectors.Four of them had a 1/2" error in the location of the slot in the motor board.They all sounded the same.I carried twelve around in the back of a bus for about five years.They start to thump pretty good when you use four per side.I was able to build 24 bass cabinets out of 25 4'x8' sheets.About four hours per box for build time.The K-horn is much harder to build because of the compound miter joints and the fasteners going in to the edge of the 12mm ply.A good winter project for the the Inca or Powermatic 66 owner who has a shuttle box.Buy a used pair. Quote Link to comment Share on other sites More sharing options...
WMcD Posted September 7, 2000 Share Posted September 7, 2000 My experience is the same as indicated above. If one tries to maximixe utilization of the boards, and also taking into consideration of the size of the driver, there is a pretty tight sqeeze to make things work. Overall, I think it is not so much of a problem with performance overall. Gil 1 Quote Link to comment Share on other sites More sharing options...
Klewless Posted September 8, 2000 Share Posted September 8, 2000 djk, One of the reasons the Khorn is so hard to build is that you are working in 3-D at different angles. It is hard to visualize in the mind's eye what the various cutting angles really should be. Not like simple 90 degree cuts here. On the other hand it is a pleasure building Khorns because you start with the front panel and keep adding on, sort of like making a layer cake. Each addition reinforces the last one until you're finally done. Within reason minor variations from "theoretical perfection" can't be heard at all. But leaks in the compression chamber can spell disaster! And of course leaks from one horn section to another is also bad. ------------------ John P St Paul, MN Quote Link to comment Share on other sites More sharing options...
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