ajsons

Third.

Second.

A forum member has asked for the specs on the EVM-15L. Drew, this and the EVM-15B are not really rare like you said. They were discontinued, but you can still find them. The C15W is older, but there is always one or two on ebay. Here's the first sheet.

I was building my SK when Edgar commented on it and the SK driver in Speaker Builder. I believe he also recommended the EV,s and the use of the 6 x 13 throat. Coincidentally a music store at the time in Va Beach had a store closing sale, got two for $120 each brand new. No, I never had the SK woofers. I can't comment on that. I've been listening more critically lately to my SK with the Classic as the other channel. Together, they both sound great, the Classic seems to "enhance" the bass output of the SK. But it's really the Classic that dominates the bass, and once I build another one, they will be my primary system. The 350hz crossover is for the Classic, and yes its mid driver, the T-30 can handle lower xover point. I have second thoughts about the 350hz idea, the other option is to build the 400hz ESN instead. This thread by Neil is really about the SK crossover, so I'll post a copy of the spec sheet for the EVM-15L under Technical Questions, the University Classic thread, and I'll meet you there if you want.

That's OK. I know it will be worth it.

I haven't seen it but I can tell it made a big impact on you. These avatars really speak our minds in a silent but powerful way. It probably has been done before, but a thread on meanings of member's avatars and usernames will be really interesting and entertaining.

Thanks, Al. The good news is I stll have left-over parts from the ALK crossover build...wires, solder terminals, screws, wire ties...etc. I learned a lot from that too, (soldring litz wires, proper coil placement, parts layout..etc.) It gets you ready for a larger project..the ESN's. So, I'm ready, can't say the same thing for my wallet! LOL!

Little Al (awsjr), Why not? Dogs can do that!!! Big Al (Al K.), I remember when the ALK's first came out, you made a list for forum members of ways to reduce the cost of the ALK's without sacrificing performance. I just did a rough cost estimate for the ESN....Can you do the same thing for it? Por favor? Al S. (Armando)

Here's an enlarged version of that wallet size picture.

DaddyDee, There must be something interesting about your choice for an avatar.

Daddy Dee, Yes, that's a cobreflex in a University Classic...That's the normal configuration of the Classic. Thanks for the interest on my avatar and this post. My cobreflexes are halfway thru the sandblasting process for a new paint job. I had to borrow the top from my SK for this thread. Here's the Classic with the grille off.

Here's the low freq section.

Thanks for the pictures. I am getting more bass from the University because it is a better horn. The EV specs are perfect for use as a horn driver per Keele. They are cast frame and better built. John Warren, in one of his posts, talking about Khorn improvements, said "A cast frame woofer would help too...The K-33 is a piece of sh*t structurally". In another post, he said about the C15W (the woofer for the University, still talking about the Klipschorn, "The University woofer does a better job in the folded unit than any *vintage* driver I've listened AND measured". My suggestion for a REAL mod, change the SK's throat to a 6 x 13, and install a cast frame woofer like the EVM-15L. Or the C15W. Like Al K., I prefer the breadboard construction for the crossovers. I split the ALKs into two sections so if I decide to upgrade or change crossover poitns, I only have to build a section and not the entire crossover. I am building a second set and the high frequency section will cross at 3500hz. The low section will cross at 350hz. I can swap sections at will, depending on what drivers I am using. The transformer taps are also terminated at the terminal block, tap selection is done by moving the midrange connections. Here's the high freq section.

Here's a front shot. I think if you use the ALK crossover instead of the N-3, maybe crossed higher, this will be a real good system.

Tricertops, I was trying to understand the relationship between driver's Fs, horn's Fc to come up with a driver that's best suited for the Classic. The C15W's Fs is 58hz, the Classic's Fc is 50hz . Maybe a driver with a lower Fs will be a better choice for it, I don't know. Right now I have an EVM-15B in it. I have to do more tests. I personally believe that the C15w and the other components of the Classic are very good drivers, although I have not tested (don't have) the HF-206 tweeter. I have the Cobreflexes, but they're waiting for final sandblasting. You may want to consider this University system. It doesn't take up as much space as the Classic. It uses the same components.

Chris, did you try to sell your Klipschorns yet? Man, those are sharp-looking Khorns. I will keep them if I were you. What kind of mods are you thinking for your Speakerlabs?

I just want to see the underside of the pc board, to see how you laid out the coils, but post whatever pictures you have, we can learn from each other.

(I can't stop). The more I look at that picture, the more I like it. Referring to the factory plans, when braces were added to the Classic's doghouse, it reduced the back chamber into a little more than 1/3 of the original volume, but it looks like there was no concern for the volume in the first place anyway. As Steve Schell mentioned, gaskets were not used, and the hole for the driver wires was not sealed. The same is true with my Classic. Here's MY understanding, or MISUNDERSTANDING of horns Fc. (This is a true or false test on my part). Please tell me where I got it misconstrued. Horns generally, do not go down to Fc (flare frequency cut-off). Horns are designed with an Fc lower than the desired real cut-off (Cohen's approach..., if you want response down to 50hz, design a horn with a flare of 40hz) The response down to Fc can be achieved by adjusting the back chamber (Edgar). Drivers Fs must be close to Fc (Edgar..somewhat Cohen, too. Cohen looks at two numbers, the flare frequency, and the desired cut-off. Also, the mouth is terminated using the desired frequency cut-off, not the flare frequency). The true cut-off is the -3db down point Maybe when I fully understand this, I should be able to choose the best driver that fits the Classic, and maybe improve the low end.

What you mention here are exactly why I wanted to post this thread. I like the Classic very much, and have chosen to replace my SK's with them, but not quite sure which direction I will go. I can build another one exactly just like what I have now, but beefed up (braces,etc). Or, I can build the Dean, just like Q-mans, also beefed up (my original plan). Or, I can build modifed versions of the above, (one) to reduce the size and (two) to improve the low end, if needed. I haven't earned my horn design badge yet, and by picking your brain, and others on the forum, I like to come out of this thread with enough knowledge to improve on the Classic, or build a set of good horns. I know Andy and JC will be interested too, based on their posts. I like the picture you posted. I was worried too about the volume of the back chamber of the EV's, but it looks like the driver end of the enclosure, (Classic and this picture) should be easy enough to extend to get more cubic inches. How do you size the back chamber? I am aware of Keele's formula for horns BC. Dr. Edgar has different volume recommendations based on whether the horn is eight-size, quarter-size, etc. I believe Bill Fitzmaurice uses the bass reflex formulas, I'm not sure. I don't understand his approach. Abe Cohen has little info in his book. Dinsdale's formulas obsolete? (I'll stop for now, I got more questions.)

It's a pretty speaker, looks like the Georgian and the Patrician, but I don't understand it.

(I'm back from the hospital, my son will be ok.) I'll reply to your first three posts in the reverse order. The easy ones first, then your horn design approach last . Cohen's book covers a lot about horn theory and horn design, much more than "Building Loudspeakers and Enclosures" by Davis. About three months ago, bookfinder.com listed this book for $6.50. Now it is priced like Cohen's book. I have a torn copy and lost my chance to get a replacement for under ten bucks. The Centurion has puzzled me. I can't find any plans for it. Twenty years ago I called EV and asked for a bunch of literature, spec sheets, plans, etc.they sent me a large package for free. At the time I didn't know much about their horns like the Patrician, Georgian, etc. I got the plans for those but not the Centurion. I found these pictures on ebay. Looks cool! But I can't figure out the folding. Maybe a forum member can explain it.

Drew, About your ALK's crossover, it looks like you used an additional board to hold the caps and palced all the inductors underneath it, am I right? In my understanding, ALK's are series crossovers. If you take out one part, it screws up the others.

Dana, Thanks for stopping by at my post. Now I feel like the thread just started. I sent you an e-mail. I can only stay on line for a few minutes. (My son is in the hospital with a broken arm (skateboarding accident). There is one book on ebay right now. http://cgi.ebay.com/Hi-Fi-Loudspeakers-and-Enclosures-RARE-FIRST-ED-1956_W0QQitemZ5846527026QQcategoryZ50597QQssPageNameZWDVWQQrdZ1QQcmdZViewItem Or you can try bookfinder.com, type the title or/and author. The price varies. Some places sell it for as much as $300.00 bucks. I was very lucky I got mine (first edition) from a bookstore in Ireland from the same website, they didn't know the US value of the book. $7.00 plus 12.00 for s/h. It is in like new condition. No tears, not a single pen or pencil mark. There is also a second edition, laser copy being sold by torres1016@yahoo.com for about $19.00. I have both copies and there is lot of changes on the second. Dana, I will post when I come home tonight.

It looks like everyone else had stopped by to take a peek, except Dana.

Thanks, Chris. The SK's have 6 x 13 openings. According to D-man, 3" is too small for the EV that I used.