mungkiman Posted March 25, 2002 Share Posted March 25, 2002 I would appreciate any advice you can offer to my situation: Currently, I own a pair of stock La Scalas. I was told they were manufactured in 1973. I have the opportunity to purchase K-horn cabinets, and was thinking about building some K-horns from the La Scala components: Type K-447 K-77 driver for tweeters K-55-V driver for K400 horn ¿Woofer (can't see yet)? Ser# 1L885/6 Crossover type AA I would appreciate guidance from anyone with specific, helpful knowledge, or a reference to another forum discussion on the subject. Thank you very much. Quote Link to comment Share on other sites More sharing options...
JohnA Posted March 25, 2002 Share Posted March 25, 2002 The La Scala used all the same components the K-horn uses for the same year. If the K-horn cabinets are Klipsch-made, then you '73 vintage La Scala parts will be ideal. If the K-horn cabinets are not Klipsch-made, check the slot the woofer "fires" through. If the slot is 3" x 13" your K-33 woofer is ideal. If the slot is 6" x 13" you'll need a different woofer for optimum performance. You can call Klipsch or e-mail djk (Denny Klietsch sp?) for recommendations. If they are not Klipsch-made, be sure they are well made. The squawker and tweeter will work in the upper section no matter how the bottom is made. John Quote Link to comment Share on other sites More sharing options...
mungkiman Posted March 25, 2002 Author Share Posted March 25, 2002 Thanks for your help thus far, John. Where exactly is the slot that the woofer fires through? There are 4 slots, 2 high and 2 low, that measure approximately 3"X13". These slots are 1/2 an arms length inside the cabinets, and difficult to measure precisely. Let me know if I am measuring in the correct spot. Thanks again. Quote Link to comment Share on other sites More sharing options...
Klewless Posted March 25, 2002 Share Posted March 25, 2002 The slot is right in front of the speaker inside the compression chamber. Have to remove the speaker to see it. ------------------ John P St Paul, MN Quote Link to comment Share on other sites More sharing options...
hetmann Posted March 25, 2002 Share Posted March 25, 2002 I am currently involved in a similar project. I have the drivers from a set of LaScalas and two set of khorn plans. One is from Speakerlab and the other are PWK originals from 1946. I feel as though I am a pretty good cabinet maker, but these plans are challenging! There are many odd angles to cut and everything needs to fit perfectly and be air tight. My advice to you is, if the cabinets you are looking at are reasonably priced and genuine or well made copies grab them. If they are knockoffs made from partical board or MDF, pass on them. I'm waiting for the warmer weather to start mine and am building a 1/2 size set in the interim. If I could find some real khorns, I'd snap them up in a minute. ------------------ Klipschorns and Moondogs This message has been edited by hetmann on 03-25-2002 at 10:49 PM Quote Link to comment Share on other sites More sharing options...
fini Posted March 26, 2002 Share Posted March 26, 2002 hetmann- Are you documenting this project? It would be fun to see some photos. I'd like to see a scan of those original '46 plans, too. Where did those come from? Have fun! fini Quote Link to comment Share on other sites More sharing options...
hetmann Posted March 26, 2002 Share Posted March 26, 2002 I'd be happy to post my progress if anyone is interested. So far, I have acquired the drivers and plans. I wish there was someone in the Denver area with some khorns I could look at for construction details. And of course I would love to hear them (hint, hint). It's been over 20 years since I've heard these. I have AA crossovers and plan to use those initially. The 1946 plans are sketchy and presume you know how these go together. They show the larger 6" throat. Since I have K33 woofs, I will be using the 3" throat unless someone here can tell me different. I plan to use the best 1/2" baltic birch I can find with cherry veneer on the visible surfaces. ------------------ Klipschorns and Moondogs Quote Link to comment Share on other sites More sharing options...
bigdnfay Posted March 26, 2002 Share Posted March 26, 2002 hetman, i'm in the same boat.one set of plans says 3" and the other says "6. i have a pair of 76 k-horns. guess i'm gonna have to open them up to find out. my question is do all k-33's(cts,eminence,etc.)use the 3"x13" throat? Big"D" Quote Link to comment Share on other sites More sharing options...
hetmann Posted March 26, 2002 Share Posted March 26, 2002 You know I'll have to defer to others more knowledgeable than I on this one. I have heard various snippets about throat size and conducted numerous searches on the topic here in the forums. At this point, I just don't know. I have heard that it matters and it doesn't matter. Oh baby I just don't know! ------------------ Klipschorns and Moondogs Quote Link to comment Share on other sites More sharing options...
mungkiman Posted March 26, 2002 Author Share Posted March 26, 2002 Thanks to everyone who has participated in this forum. I think these cabinets are a Speakerlab kit. The construction is quite good, but the material is mostly particle board with some plywood. The cabinets are inexpensive enough that I would consider buying them to tear them apart and see how they were made. I could use the pieces as templates, and build new cabinets with better materials. Has anyone done this? Can anyone help me identify the woofer in these, before I decide to remove them and measure the slot they fire through? They are 15", the back of the cone is ink-stamped C-189, and the back of the square magnet is ink-stamped 15FPHH4D 677708. Any ideas of what they are? A little more: The mid-range horns are fiberglass, with Atlas Sound PD-4V drivers. The tweeters are not marked. The crossovers(?) are Essential Sound Products L-Pads. The sound is good but not great. The easy thing for me to do would be to put the La Scalas (upside down) on top of the K-horn lowers, play the unknown woofers through the AA crossovers, and see how they sound before tearing apart all 4 cabinets. I could keep my La Scalas intact, I could combine or swap components, or I could build new from scratch. If anyone can help I.D. my woofers, it might help to define my project. Hetmann, I would enjoy seeing your project documented. Hetmann and Big"D", if either of you would be willing to share xerox copies of your plans, I would be willing to pay for your time. I know they are available on E-bay, but I would rather help defer your costs than fill his pockets again.I would also be willing to share any knowledge I gain in this process. Sincerest thanks to all. Quote Link to comment Share on other sites More sharing options...
WMcD Posted March 27, 2002 Share Posted March 27, 2002 I can offer some advice from experience. My brother in law and several friends got Speakerlab kits. I went through the horror of building variations of those using 3/4 inch ply. It was a horror because of the work involved. I'd say that if you have a functioning set of Speakerlab bass horns, stick with them rather than trying to start from scratch. One moderator here reported that they are pretty close dimensional matches for the real McCoy. The McCoy used 1/2 inch ply in most areas and reportedly has recently changed to MDF because of costs. Other builders have expressed strong opinions of the virtue of ply over MDF. My guess is that these are overstated. As long as the stuff is secure and sealed tight, it probably works well enough. Another variation in the bass horn design is whether the back chamber communicates to the volume created by the "wedges" at the top and bottom of the cabinet. Too difficult to explain. If you have the Speakerlab plans, you'll see there is an option of cutting a notch. Apparently Klipsch did this to increase back chamber volume, Speakerlab copied it. Then Klipsch dropped it, and so did Speakerlab. The "slot" is a matter of long debate. There is no question that the actual "throat" of the bass horn is 6 x 13. This is because you'll see there are two 3 x 13 ducts leading off of it, going up and down. However, there is a 3 x 13 slot in the motor board. In the '70s and '80s Dr. Bruce Edgar tried some analysis of the effect of the small slot. He equated it to a small throat. I believe he missed the boat on this. He got some support from Hope in that they ran some comparisons of K-Horn comparison with and without. It is different, but which is better, is tough to say. It is not really an issue of throat size. I don't see that a woofer parameter is matched for the slot, no slot issue. It is my belief that PWK used the small slot to form a chamber in front of the woofer. There is good theoretical reason to believe it would improve the high end response of the woofer, it wasn't working well above 300 Hz. So, if your Speakerlabs have that slot, I wouldn't mungki with it. I think the number you mention is from the Speakerlab bass driver unit. Edgar was very critical of it. The parameters are very different than the K-33. The problem is with high end response. It just creates more problems above 200 Hz. If you take the K-33s and bolt them into the Speakerlabs, I think you'll be well served. Speakerlab used a fiberglass midrange at the start and then switched to cast aluminum. Klipsch had a metal, probably aluminum for the K-400, and then switched to a composite for the K-401. The 401 is doubtlessly more robust than the early Speakerlab fiberglass. If you have the early Speakerlab fiberglass, using some Moretite to damp them might keep you happy. Speakerlab used two tweeters that I know of. One was plastic version of the ElectoVoice T-35 or Klipsch K-77. I can't comment on how good the copy works. The other was a much more rudimentry horn loaded tweeter with a smaller cut out. You'll see that Speakerlab put the tweeter to the side of the midrange and long side vertical. Probable this was to save material and height. Klipsch puts it center on top and long side horizontal. Please contact me if you want more info. Gil Speakerlab used at least two crossovers that I'm aware of. One used a set of switches to adjust padding, the other L-Pads. Neither use an autotransformer like the Klipsch A and AA series of networks. Quote Link to comment Share on other sites More sharing options...
hetmann Posted March 27, 2002 Share Posted March 27, 2002 I do not see the "notch" Gil is talking about on my Speakerlab plans. I presume these are the latest version they produced. I'm happy to share my PWK plans, email me offline. ------------------ Klipschorns and Moondogs Quote Link to comment Share on other sites More sharing options...
bigdnfay Posted March 27, 2002 Share Posted March 27, 2002 I opened up my bass horn this morning and found the throat to be 3"x 13".There were notches cut to expand the rear chamber. these are a mid 70's model and these findings may have changed in newer models. Took some other measurements of different parts and their not the same as on the plans I have.I need to examine this further. Big"D" Quote Link to comment Share on other sites More sharing options...
mungkiman Posted March 28, 2002 Author Share Posted March 28, 2002 Gil, Thank you for your considerate and thorough response to my questions. I am sure these are Speakerlab kits. It will be easy enough to swap the accessible components, but getting to the La Scala woofers will be a challenge. These La Scala cabinets, black "utility" finish, have bottoms that are nailed in from all 4 sides. My true interest in all of this is to "hear" a Klipschorn again. I don't like the idea of performing surgery on the La Scalas, partly because I might like them back as La Scalas when I can afford a true pair of Klipschorns. Something also tells me that if I were to take on a project as large as trying to build from scratch, I should follow PWK plans rather than Speakerlab's version. I should have plans to look at soon (Thanks for the offers, guys!), so I will endeavor to locate the notch you mentioned on plan, and in these cabinets. I understand the principle, but not the location. I will post again when I decide to start cutting, or if I think I can afford some true Klipschorns. Again, thanks Gil, for the background/history, suggestions, and facts. I truly appreciate your knowledge, and your willingness to share it. Quote Link to comment Share on other sites More sharing options...
hetmann Posted March 30, 2002 Share Posted March 30, 2002 Just a little update for everyone following this thread... I have been building a couple of half size khorns to practice and see how things go together before ruining a bunch of expensive material. I have been following the Speakerlab plans closely and for the most part things are going together well. The angles specified for the edges of pieces are pretty good and have gone together well. You definately want to make some jigs to help with accurate cuts. I have also discovered that it is very helpful to scribe a centerline on almost all the pieces as this helps in getting everything to line up during assembly. And I have found a couple of changes I plan to make to the full size cabinets to ease their construction. ------------------ Klipschorns and Moondogs Quote Link to comment Share on other sites More sharing options...
WMcD Posted April 2, 2002 Share Posted April 2, 2002 Attached is a schematic for a Speakerlab crossover. Note model numbers for woofers 8 and 4 ohm and change of inductor value. Gil Quote Link to comment Share on other sites More sharing options...
mungkiman Posted April 11, 2002 Author Share Posted April 11, 2002 Gil (and everyone else following this thread), I have been on vacation for nearly 2 weeks, and apologize for the delay in correspondence. You all know I am apprehensive about cutting the woofers out of my La Scalas simply for an acoustical experiment. I hope I have another option... I would like to buy 2 Klipsch woofers to put in the speakerlab cabinets (the other components are an easy swap), rather than "open up" the La Scalas. This might be a reasonably economic way to do my project, with nothing irreversible. What would be the best source for a replacement Klipschorn woofer? Remember, if it makes a difference for compatibility, that the other components are from 1973. I have seen woofers on E-bay, but I would appreciate learning of other quality options. What, specifically, should I be looking for? Thanks to everyone involved. Quote Link to comment Share on other sites More sharing options...
JohnA Posted April 12, 2002 Share Posted April 12, 2002 There is no cutting required to get the woofer out of a La Scala. The botton plate unscrews and comes off. The only place to get K-33s is from Klipsch. Eminence cannot sell them directly. Klipsch only charges $110 each. John Quote Link to comment Share on other sites More sharing options...
k2dx Posted April 12, 2002 Share Posted April 12, 2002 There's a pair of k33's on ePay now,no bids yet. Fred Quote Link to comment Share on other sites More sharing options...
Ray Garrison Posted April 12, 2002 Share Posted April 12, 2002 John, In his post four posts above yours, he mentioned that someone had nailed the bottom plate in from all four sides. I'd be afraid that if he tried to pull the nails out to remove the bottoms, he'd split the plywood and mess up the appearence of the lower sides of the speakers. ------------------ Music is art Audio is engineering Ray's Music System Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.