drewb

Rick, You are correct. They are 2" high in the catalog. I had the pleasure of going to the warehouse when I was in Cincy over the holidays. Good people to deal with with a great selection at good prices. I still believe our newbie may have to do some under-chassis cap installation. If I am not mistaken the Scott has 4 section caps in some locations. 2 of the sections where 25mf-35v for the preamp section. He will need to determine what the big caps are and what needs to be done. As everyone has said better pictures, along with some under-chassis shots would help.

If I am not mistaken the original can caps in the Scott are 2" high. Parts Express says the diameter is 1 3/8". Looking at the picture it appears the ratio of height to diameter would make them at least 3" tall. This is the problem the poster is trying to solve. It appears as though someone has replaced the original Scott cans with newer (and taller cans). Unfortunately these 2" cans appear to be unobtainium. I have taken to installing radial caps under the chassis to solve the problem. In this case he would want to remove the offending cans. I have found that sink hole plugs from the plumbing department at Home Depot make an acceptable looking hole filler.

Armando, Did you replace the original Speakerlab woofer with the EV? I would be curious as to your impressions of the differences. I tried the 6 x 13 opening with the Speakerlab woofer. The result was a "hole" around the crossover point. Have you tried the EV with the 3 x 13" opening? Moving the crossover point to 350Hz would solve the problem if your midrange can go that low. Yours appear to have that capability. I will need to look at Al's Trachorns to see if they can do it also. I will look up the specs on the EV. It is a rare woofer that has the correct specs for the khorn loading. Your crossovers look great. I went with the PC board because 1) I make PC boards all the time and 2) my breadboard attempts stunk. You, Al and others in this forum have shown me that it can be done correctly. I was under the impression that the University was not as powerful a horn as the khorn. I'll look at your design and construction post more closely. Are you going to try the es crossovers on the Speakerlabs? I would be interested in your results there also.

Here is pic of the top side of the PC board. I understand from another thread that you are getting more bass from the University's. If that is the case I would suggest that your EVM-15L woofers may not be a good match for the khorns. K33's are still available from Klipsch. This is what I will install someday.

Thanks Al, I will try the 1.5mh inductor. I am not sure what I am hearing but I know removing the inductor isn't the right move. Attached is a pic of the underside of the PC board for Armando. They were taken before I switched to lintz coils. The lintz coils really are needed to make the ALK crossovers shine.

Armando, The board is a printed circuit board of my own design. I wanted to build as solid a crossover as possible. I just got tired of breadboarded construction. If you are interested I can post more pictures of the construction. I believe you are right about component removal. So far it seems that the bass has a bit of boom. This may be due to the impedance change. I just wish I could figure out the right inductance for my woofer. I guess I will need to experiment.

For the Speakerlab woofer use the 3 x 13" opening. I routed a 1/2" radius on the outside of the motorboard opening. This makes a flared opening like they are doing now on speaker ports. This smoothed the bass response noticeably. I stapled plastic screen over the back of the woofer and very loosely stuffed the back chamber with polyfill I got from Walmart. This seems to increased the bass. I put water pipe insulation from Home Depot on the corner sealing joints. A good seal is probably the most important factor (IMO) for good bass response. Currently I am using the woofer without the 2.6mh inductor, ALK may want to comment on whether this is a good idea or not. It may destroy the constant impedance that is a major feature of his design. I used a 2.4mh inductor but I am unsure what the correct value should be since the Speakerlab woofer I have is 8 ohm nominal. I wrapped the midrange horn with several layers of rope caulk. This removed all of my midrange complaints. I made a 3/4" spacer out of plywood in between the base and top sections. This made the appearance much more acceptable and "Klipsch" like. Originally I had the "wave aperture" tweeters. This may be what was described earlier as "better" tweeters than the EV35. They are not. They are EV35 tweeters with Speakerlabs own (and inferior in design) horn. I was able to get a set of EV35 horns from Epay. This make my khorns into Klipsch clones.

The Speakerlab woofer is fine. Don't let Edgar fool you into thinking it is inferior, it is not. I have some suggestions (mods) if you are interested. Evidently insert image does not work but file attachment does. This limits me to one picture per post, so here is the picture of my homebrew ALK's:

Great thread! I built Speakerlab Khorns over 20 years ago. After many missteps I installed ALK universal crossovers. I now have great sounding horns. Speakerlab never did get the crossovers right, IMO. In reference to the original post the problem is with the design, not the components. High quality components cannot makeup for bad design. You could still build a set given the necessary cabinetry skills. I would use a Klipsch K33e woofer, ALK's trachorn midrange and a JBL tweeter. Here is a pic of them:

Thanks AL, I guess a test of a 2+0.2uf bypass would still be interesting. I am interested in the 10k Hz and above area. How are you doing your ESR test? Maybe I can rigg something up. I am always looking to see if I can quantify and prove/disprove some of these common audio assumptions/myths. The search for the truth continues. Drew

Al, Maybe the 40uf cap would be easier to measure. How about comparing the 39uf fastcap with the 1uf harmony bypass to the 2-20uf solen combination? I would love to do it but I lack the caps and equipment. The data you provide in this forum has been very valuable to me, keep it up. Thanks, Drew

Hi Al, I know you don't think much of bypassing but would you do your quick test on a Solen 2.0uf fastcap bypassed with a 0.2uf Hovland? I know you say that bypassing only works at microwave frequencies, let's see it. By the way your quick rough test is the only real data I have seen that shows a difference at higher frequencies. I think you are on to something here. Drew

Hi Marvel, The ST70 has been rebuilt with good poly caps and an SDS cap board. The cap board really beefed up the bass. I use it now with a set of restored set of AR 2ax's. The short wall was added to hide ducting for the HVAC system. I added it myself so I know the before and after. The loss is minimal, nothing compared to the importance of a good tailboard seal. Since I put in the corner myself I was able to pay extra attention to the squareness and plumb of the coe rner. This, along with some pipe insulation allowed me to make a tight seal. There is another thread going on here that shows a poor seal creates a 250hz hole. I can verify this. Attached is a picture of the room looking away from the speakers.

I built a pair of the Speakerlab khorns starting back in 1984. I finished them in 2002. After much research I found that the woofers were made in house. Speakerlab published a lot of different specs for these speakers. I have four different sets with Vas (M3) of 0.125 to 0.612. The best figure I could find was 0.312 which is very close to the K33 of 0.343. I made a hornresp (horn analysis software) model of the two woofers. The main difference is the Speakerlab woofer starts to roll off at about 375hz. This is what Bruce Edgar complained about. Stuffing the back chamber with some fiberglass seems to have solved this problem. From all my research and experience the Speakerlab woofer is a pretty good copy of the K33. The midrange used the atas pd-5vh same as Klipsch. They offered serveral tweeters. The EV versions were the t-35 and and t-350. They had a wave aperature model where they put their own horn on a t-35 driver. I had these, the best thing I did was to get a set of EV t-35 horns from Ebay. The main problem I had was with the Speakerlab crossover. It was a poor desing at best. When I put in a set of ALK crossovers these speakers began to sing. I am running them with a Fisher 500C amp. They are as good as any Klipsch I have heard. (I can't speak to the latest offerings, the newest pair I have heard was circa 1980.) Other corrections I made were removing the "ferrofluid" from the tweeter and midrange (I can't get to it in the woofer). Wraping the midrange in rope caulk and adding pipe insulation to the tailboard for corner sealing.

Free software is available for horn modeling. I have used it to sucessfully to build a simple model of the Klipschorn. You can get it at: http://www.users.bigpond.com/dmcbean/.

Ok, since you have your motorboard out...... I modified my motorboard when I had it out and the speaker dismounted. This is drawn from modern tuned ports. If you look at all modern tuned ports or tubes you will notice that they have a radius. I have been told by an expert that this was a major advancement in tuned port design. I am not sure of the theory. I took a 1/2" router with a rounding bit and put a radius on the Klipschorn box side of the motorboard. This has smoothed my bass noticably. This is a mod based on modern theory that PWK did not have. I have no idea if it is incorporated in the modern Klipschorn. Anyway, what can it hurt?

Yes, April fools! I wouldn't have tried this one anywhere else for fear of becoming the source of the latest tweek fad. We have great defenders (like Al) of what is real and sensible. I am beginging to wonder about Gil. His reply shows a dangerous understanding of the tweekers mentality. Adding Autoformers to my system (the dreaded Speakerlab's) was the best upgrade I have done. PWK showed his true genuis when he added these to the crossovers. They are overlooked as fundimental part of Klipsch design. Thanks to Al for finding a source of quality Autoformers for new crossovers.

I have found a way to eliminate the Autoformer from the midrange portion of the crossover. If your cornerhorns, heresy's etc. have an autoformer you can bypass it. Just add old magnets harvested from thrown away computer hard disks. These can be removed from the old hard disk by unscrewing the cover and removing the ceramic piece that your screwdriver just stuck to. The magnets will attach themselves to the squaker driver. I find that 3 of them equal spaced is just perfect. The result is a sound that is more magnetic with a certain hard to put your finger on ceramic tingle. The magnets reduce the db output of the midrange just like the autoformer did but without that nasty autoformer distortion. Caution: I am not sure what this would do to the warranty.

I took the time to create a Hornresp model (software for modeling horn loading) for the two woofers. They are more similar when put into the bass bin than the numbers suggest. I did this to try to convince myself to invest in k33's, the results were a surprise. Here is the K33e woofer. Here is the 1508S:

Others more familar with Klipsch patents can correct me if need be but as far as I know the original bass bin patent had expired. Later patents were on other systems and crossovers. Speakerlab never infringed on Klipsch crossover's, not even close. Reverse engineering is legally protected practice. A recent rewrite of the intellectual property laws had specific language protecting it. PWK enjoyed full patent rights, licensing to others during the patent life and founding a very succesful business based on the patent. Any thoughts that Speakerlab "owed" anything to PWK are just fantasy.

My point is that the blueprints are dimensionally accurate. Since you mentioned it I will put in my $0.02 worth on cut and fit. The Klipsch cornerhorn requires accuracies that cannot be achieved on most home equipment with normal skills. Most home table saws are out of square somewhat. Even 1/16" over 3' will ruin the fit of a Klipsch. Even if you know how to correctly square a table saw most home units will not hold it long enough to cut all the pieces (guess how I know that). The bevel cuts need to be +-1/2 of a degree. Again this is difficult with most home tools and hard to accurately measure. Unlike many cabinetry projects there are not just a few critical dimension you can put a * by. All of the internal fit dimensions are critical. They all add up to introduce the 1/4" critial junction errors you reported. You cannot "trim to fit". An adjusment on one piece just messes up the alignment. Many good cabinet makers would be like a fish out of water with this. Critical compound angles and multiple part fits just are not part of ordinary Cabinetry. I am not suprised that Speakerlab delivered low quality pieces. I would imagine that they contracted out to get the cutting done with common plywood. With normal tolerances and methods you cannot achieve what is required. I am sure that Klipsch on the other hand kept the cuts internal and used jigs and fixtures to assure accuracy. I point this out not to discourage anyone from attempting to build a cornerhorn, just in the interest of information.

If there were dimensional errors I didn't find them when I built mine in 1983. I have never heard another builder who said there were errors. The only other plans I have seen were done on in metric by a German fellow. They are available here: http://baseportal.de/cgi-bin/baseportal.pl?htx=/Data/exdreamaudio/bauplaene&db=bauplaene&cmd=list&range=0,20&cmd=all&Id=10 and http://home.datacomm.ch/nschroeder/Bauplane.htm. If I were to build on today I would use these plans as a check but using the Speakerlab plans as "known good" dimensionally.

A patent, unlike a copyright which can last forever, expires after 15 years. Sometimes a 3 to 5 year extension is obtained. Anyway the Klipsch patent had expired.

I can't comment on Speakerlabs's cuts since I built mine with very exact cut and fit. Yes, I aggree that I have pushed mine toward the true Klipsch design. My comments are that they can be true clones. Cost and time I have much more into them than they are worth. Cost wise I am far ahead. The jury is not in on the tweeter placement. Even Al thinks the side placement may be better. I am still trying to decide. Mine are mounted on the ouside corner of each speaker (they are mirror images). The soundstage seems real without any hotspots. I am going to use my audio generator and SPL meter to get an emperical result. I have the fiberglass mid horn. As far as I can tell they took an exact cast of the Klipsch fiberglass version. Unless you are referring to the tophat being a couple of inches taller they are identical. I'll report on this as I get the real world data.

These speakers are badly misrepresented, the seller is grossly misinformed. They are somewhat fradulent, including the Klipsch badges. As a Speakelab K-horn builder and owner I would point out the following: The tweeter is Speakerlabs own "constant-directivity" horn. I started out with these and found the response is optimized for to low a frequency and they have a downward spl slope as frequency goes up. They are no were near the K77 tweeter. The midrange horn drive is not the Altas that Klipsch used. I am not sure what it is but be advised that most midrange drivers are not designed to go down to the 400hz crossover point that the khorn requires. The crossovers are Speakerlabs. I tried many attempts at using Speakerlabs crossover variations over the years. I concluded that Speakerlab never got close to a workable design. These speakers could be used as the starting point for a good set of horns. You can purchase t35 horns on Ebay for about $50.00. Using the tweeter magnet and diaphram you would end up with a pair of k77's. The Alas midrange drivers can still be found for under $100.00 apiece. ALK crossover's can be purchased or built. I would bid with these "upgrade" costs in mind.