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Cornwall and Universal


greg928gts

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I've been inspired over the last couple of days!

For the heck of it, I brought my Cornwalls over to my house yesterday and hooked them up with ALK Universal networks.

My Cornwalls have 2" throat, wooden tractrix-like horns in them, with BMS 4592 drivers. Expensive? Yes. Overkill? Probably. But man do they sound nice! I also had the Crites cast-frame woofers and stock K77 tweeters.

I've been meaning to do this for a while now, just too many other things to tend to, so it got stuck on the back burner. When I first upgraded my Cornwalls, I got some design help from Al on the crossovers, which I built myself. I would describe them as Universal-like crossovers with a 600Hz crossover point between the woofer and the mid. The initial listening tests with these speakers revealed wonderful potential, but some issues regarding the sound in the mid-bass region. I just never got back to working on the crossover to clean it up until now.

So I brought them over to the house and disconnected the 600Hz crossovers and hooked up regular ALK Universal A networks in their place (400Hz and 6000Hz). There was just too much mid-bass coming from the woofers, actually very much the same type of problem I had with the first listening test and the 600Hz crossovers many months ago. On a whim, I tried changing out the Crites woofers and put the stock K33's back in, and the mid-bass problem was greatly reduced, with no lack of low bass. I'm not exactly sure what to make of that, but that's what I heard.

I played around with some different inductors and settled on a 1.8mHy inductor to replace the 1.3mHy in the Universal, and that really cleaned up the rest of the mid-bass hump.

I'm going to do a couple of things. I'm going to break in the Crites woofers, which I'm not sure has been adequately done since I bought them. Then I'm going to put them back in the cabinets and do another listening test. I'll see if I can find an inductor that cleans up the mid-bass with the Crites woofers in my Cornwalls.

I'm having fun with it! Just listened to an entire CD from the Dallas Wind Symphony, music by David Maslanka by Reference Recordings. A wonderful sounding CD with very dynamic music. The modified Corns handled it extremely well and presented good imaging, a nice wide soundstage, big smooth midrange, and the typical fat, low bass that they are known for.

I don't see any reason why one of the Cornscala variants couldn't be a very high-end offering, done right within the Cornwall cabinets with the large-format midrange, Beyma tweeters, and a new version of a familiar crossover. These horns that I have in mine fit just fine with just a little cutting, and the sound is very close to the V-Trac horns used in my Khorns. As I said before, it's expensive, but for most people, building new cabinets is expensive too, and the sound quality available with the large format midrange is tough to beat. I'm curious about other woofer possiblities for my Cornwalls too. Oh, and I definately have to find a way to get the Beyma tweeters in there.

Greg

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I am EXTREMELY sorry I ever allowed you to build my Universal networks!

Stick to building cabinets. This is what you are qualified to do! "Playing around" with networks is not professional or wise. Changing the inductor from 1.3 to 1.8 mHy is insignificant and serves to upset the impedance unless the associated cap is also changed. you don't know what you are doing. To move the crossover frequency up you REDUCE the inductance value, not raise it! LEAVE MY DESIGNS ALONE!

Al K.

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I was wondering about this. I didn't think a universal would go in a cornwall but I thought maybe there was some new universal or something new anyhow. I'm no longer confused.



I have a very nice pair of those ALK cornwall nets (the downloadable DIY) built by DeanG quite a while ago and my corns sound fantastic. AlK never bragged about that network much, but it makes a big difference. I have A/B'd it against a stock recapped Klipsch B network and it's not even close. The only issue is that I paid $500 for the corns and $700 for the networks. Of course you can build them cheaper but I wouldn't do that.

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Mark,

I didn't remember you had one of the few Cornwall networks I made. I think I only made about a dozen sets. Even it is now outmoded by the AP12-600 and AP15-6000 or ES5800 set that will work fine in the Cornwall or Cornscala. The Universal was NOT intended for that speaker or I would have made them for Cornwall owners too. My first prototype of the Cornwall network was 1st order like the Universal. It didn't sound right according to the guy who auditioned them (Allan Songer). That's why it went to 2nd order. The Cornwall woofer goes much higher then the horn loaded Khorn or LaScala woofer and a 1st order filter yields too much overlap. The tweeter needs to be cut back as well compared to the Khorn. At the time, I didn't want to use two transformers as I do now, so I taped a single one just as Klipsch did with their designs. It made the level setting fixed.

Al K.

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Changing the inductor from 1.3 to 1.8 mHy is insignificant

No it's not, it makes a significant difference in the quality of the sound. If you listened to music on speakers you'd know this.

To move the crossover frequency up you REDUCE the inductance value, not raise it!

No kidding. I was trying to lower the crossover frequency. I know exactly what I'm doing. It works. Any techno-babble from you to the contrary doesn't change how it sounds to me.

LEAVE MY DESIGNS ALONE!

All it takes is a couple of little changes and they are no longer your design. These calculations are available to anyone on the internet. You don't own the idea of using inductors as low-pass filters, caps as high-pass filters, autotransformers as attenuators, and resistors for swamping. Too bad Al, I'll play around with these things all I want. I have lots of customers who appreciate my efforts to help them improve the sound of their speakers based on actually listening to music on them myself. Lots of good things coming from Volti Audio in the future.

Greg

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mark,

Yes, Dean did build a few of my Cornwall networks, but only a few. Dean quickly found out how hard that design was to build and didn't want to do it any more! He also knew better than screw around with the design! They were correctly done and well built.

Roberts,

I didn't even bother to read your comments. I'm sure they will just make me mad!

You are not qualified to design, modify or recommend other uses for my designs. All you may do is sell the remainder of the 10 sets of Universal networks I foolishly allowed you to build to support your 2-inch horn. NOTHING MORE!

Al K.

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Built more than a few of those, maybe seven or eight pairs. Not hard to build, just really time consuming and not much in the way of profit for the amount of time it takes to build them. Tough to sell too. Not many want to spend as much on networks as they spent on the speakers.

I don't see why you couldn't use the Universal for the CornScala - but you would need to knock 5 or 6dB off the tweeter. I do prefer running the woofer up little higher - it takes some strain off the horn and also produces a smoother power response.

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Built more than a few of those, maybe seven or eight pairs. Not hard to build, just really time consuming and not much in the way of profit for the amount of time it takes to build them. Tough to sell too. Not many want to spend as much on networks as they spent on the speakers. I don't see why you couldn't use the Universal for the CornScala - but you would need to knock 5 or 6dB off the tweeter. I do prefer running the woofer up little higher - it takes some strain off the horn and also produces a smoother power response.

This is why I haven't spent much time on the Cornwalls. There's a demand for upgrading them, but most Cornwall owners don't want to spend a lot of money on them.

I did have to attenuate the tweeters in my Super-Cornwalls, but had to attenuate the mid even more. The woofer just isn't keeping up. There's a lot more strain on the woofer than the mid in my speakers with a 400Hz crossover point. It seems to me that if the mid/woofer crossover point is lowered, that sends more energy to the mid and less to the woofer, and I think this would be very favorable in my speakers. I know in comparison to the energy used in the very lowest frequencies it's not nearly as much in the mid-bass, but something is something, and based on my experience, the lower crossover point sounds better anyway. To me, it doesn't matter that the woofer is capable of playing as high as 1K, it just sounds better to let the mid handle as much as it can (2" format).

Greg

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Dean,

You can fudge the Universal to work in a Cornscala, but you need to cut the tweeter back also. part of the problem with it is that there are so many Cornscala variations and each requires slightly different modifications. Not all of us are qualified to make those changes. Another reason the Universal is not a good match for the Cornwall or Cornscala is the fact that they are direct radiator woofers. The Universal is "universal" because its skirt slopes are so sloppy the frequency response of the horns determine the crossover frequency. The Cornwall and Cornscala don't have a horn loaded woofer! The woofer and squawker will have a huge driver interference window with a 1st order crossover. Klipsch moved to a 2nd order woofer filter in the B-3 network and so did I in the Cornwall networks you built. I suggest the AP12-600 and ES5800 now for Cornwell and CornScala users. That combination allows setting the squawker and tweeter to you taste. Jury rigging the Universal for use in those speakers is just a way to sell stuff you have on hand! It is not in the interest of the user.

Al K.

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Jury rigging the Universal for use in those speakers is just a way to sell stuff you have on hand! It is not in the interest of the user.

Lol. I know this line is directed at me, so I'll respond.

The ALK Universal networks that I have for sale are great networks and they'll sell in due time, and for their intended purpose. I'm not going to change the ones I have into something that someone can use for Cornscalas. Your implication that I would consider doing that is just another lame attempt on your part to try and discredit me. Bounces right off with no harm done!

Regarding the gentle slopes and "huge" driver interference window. Once again, all that might be true, but it doesn't change the fact that I really like the sound of the Universal network with my Cornscalas, after changing the inductor slightly.

Your point about there being so many Cornscala variations is true. What Cornscala owners need is someone to build custom crossovers for them.

Greg

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Roberts,

"All it takes is a couple of little changes and they are no longer your design. "

Once you start screwing around with crossovers, a subject you know NOTHING about, you associate ALK Engineering with your imperial jurey-rigs. They are truly NO longer my designs by your own admition! For the THIRD TIME: Remove ALK Engineering from the menus on your web site! As long as that remains, the implication is that you are associated with me. You are NOT!

Al K.

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Roberts,

"All it takes is a couple of little changes and they are no longer your design. "

Once you start screwing around with crossovers, a subject you know NOTHING about, you associate ALK Engineering with your imperial jurey-rigs. They are truly NO longer my designs by your own admition! For the THIRD TIME: Remove ALK Engineering from the menus on your web site! As long as that remains, the implication is that you are associated with me. You are NOT!

Al K.

Klap

If you want me to remove ALK from my website, return the royalties paid on the unsold units that remain in my stock, and I will. Otherwise, I'm entitled to continue to sell them as we originally agreed.

Roberts

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Roberts,

Your remaining stock of unsold networks is not relevant. The presence of my name on your web site represents an affiliation that no longer exists as of the time you paid off the royalties for the remainder. This act, along with your verbal declaration to terminate the agreement, dissolved the relationship. I will no longer tolerate any inference that there is ANY form of relationship remaining. For the FORTH TIME: REMOVE the name ALK Engineering from your web site!

The very fact that you initially paid the royalties for each network as you sold them, then paid off the rest in a lump payment after terminating the agreement is clear evidence you were serious about ending the relationship. Now that you have paid off the royalties in full, removing any incentive I may have had to help you sell them, you insist on using my good name and reputation by inference to do it! I will not sanction your jury-rig networks directly or by inference. AGAIN: REMOVE MY NAME FROM YOUR WEB SITE!

I will make a final point clear. I still grant you the right to sell the remaining stock, withOUT any modifications. This is all that remains of the agreement. NOTHING MORE.

AL K.

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