The History of the Jubilee

[bracurrie]

I heard an interesting RUMOR recently[:-*]. It goes something like this: Paul Klipsch passed away just after making some last modifications to the Jubilee LF horn. The plans with mods were not the property of Klipsch after he passed away. So the Jubilee of today is not the same speaker that Paul Klipsch with the help of others finished.

I don't believe in secret government conspiracies and I don't believe the above RUMOR. So what is the design history of the Jubilee. What modifications, if any, have been made to them once they started making them for sale. Even though the RUMOR is most likely false, I'll bet there is a great story here worth telling. After all, most of the self proclaimed audiophiles I've met and talked to about the Jubilee have never heard them and most are stuck on Klipsch as the funny corner horn people.

I have spent entirely too much time being entertained by the Jubilee threads in this forum and have learned a great deal. There are some skilled audio experts and experienced enthusiasts that have added their views on many aspects of the Jubilee. The passion and enjoyment only starts with listening the speaker.

Thanks.

[seti]

I am a lifetime member of the funny corner horn people club.

That is a rumor. Roy and PWK I think were working on a version with a 12" drone. Not sure if that would have made it to the product or not. Basically PWK passed and Klipsch dropped the project but the Jubilee bass bin did make it to the pro cinema line. The biggest change since it first appeared was a change in construction so that it went together faster at the factory and so the cabinet was stouter. If you look at new and old pics you'll see what I mean.

There are alot of great old threads on the forums regarding the Jubilee. Look for posts from Bodcow Boy that would be Roy who worked with PWK on the Jubilee project.

[Turbox]

Can someone post a link to this thread re bodcow boy? Also, in the last year, i think there has also been a change in drivers for the unit.

I think but not 100% sure that the Jubilee used the same drivers as the KLF30? Either way, in the last year i think that may have changed. When i purchased my Jubilee Bins(about 1 year ago) they were significantly delayed because the manufacturer who made the drivers discontinued them. I was able to get them made and delivered using the old drivers, they found some somewhere....

I think they are different drivers now, but cant confirm or deny...

[Marvel]

It's actually bodcaw boy... []

One of the reasons they redid the cut list was all the home users ordering the bass bin. It made it easier to build and stronger.

Bruce

[Chris A]

So what is the design history of the Jubilee. What modifications, if any, have been made to them once they started making them for sale.

In my conversation with Roy on the Jub bass bin redesign (i.e., the KPT-KHJ-LF), he mentioned that the original design was taking too much time on the shop floor to assemble, making sure that the geometries were correct. Roy designed the new-and-larger horizontal stiffeners to be used to locate the structural folds of the horn more completely and simply by slipping in the new stiffeners like manufacturing jigs and fastening to them, then checking the resulting horn fold tolerances after placement. Roy mentioned the decrease in assembly time and I remember it to be a 2-3x reduction in the overall touch labor time to assemble. Paint, test, and prepping to ship are apparently unchanged.

There have been machinations on the Jub bass bin veneer, with one pair being built in mahogany-veneer plywood (which dwilawyer currently owns)which resulted in a prohibitively high cost in time and materials. Now the bass bins can be ordered with veneered plywood fronts only. I've found that the bass bin fronts are pretty big areas for near field reflection issues coming from the K-402s sitting on top, and perhaps high mid-bass bin frequencies around the crossover point (~400-450 Hz) from the two bass horn mouths diffracting off the front of the cabinets. I affixed Auralex Sonofiber panels to this entire front surface of the bass bin to cut down on any near-field midrange reflections. These panels completely cover up my black-paint front panels, so I didn't actually lose money on veneered fronts. I own the original style bass bins--the ones that required more time and care to assemble, but they have reduced stiffener volume inside the horn compared with the new design bass bin.

The only horn profile change that I know about are the "mumps" on the newer K-510 horns, like the ones that Turbox now owns. These added bumps on the horn apparently help its dispersation uniformity a bit more (according to Roy). Some folks use the little K-510s on their JubScalas and JuBelles (I don't however).

The last change--the use of TAD TD-4002 beryllium diaphragm compression drivers--IS a really big deal in terms of improvement in SQ. I can't overemphasize how much this improved the last octave of the K-402/compression driver assembly: it's not even close in comparison to the K-69-A in my humble opinion.

End of Jub rumors/stories. [:|]

By the way, I recommend using a better amplfier for the TADs than a Crown D-75A or a garden-variety SET, both of which I've tried on the TADs. The First Watt F3 was a dramatic improvement over these two choices. I also don't recommend using an amplifier with output impedance greater than ~1 ohm, or alternatively stated, a "damping factor" less than ~8.

Chris

[bracurrie]

I own the original style bass bins--the ones that required more assembly time and care, but have reduced stiffener volume inside the horn folds.

Could you speak to the performance without the stiffeners vs with?

[Chris A]

Could you speak to the performance without the stiffeners vs with?

My bass bins have stiffeners - they're just not as large as the current production units. There is a law of diminishing returns on stiffener effects, and I believe that Roy and PWK designed the original bass bin with sufficient stiffeners to assure acoustic performance. The change occurred when manufacturability needs drove a design change, and I agree that Roy did a really good job in solving that manufacturability issue through redesign.

Chris

[bracurrie]

I am a lifetime member of the funny corner horn people club.

That is a rumor. Roy and PWK I think were working on a version with a 12" drone. Not sure if that would have made it to the product or not. Basically PWK passed and Klipsch dropped the project but the Jubilee bass bin did make it to the pro cinema line. The biggest change since it first appeared was a change in construction so that it went together faster at the factory and so the cabinet was stouter. If you look at new and old pics you'll see what I mean.

There are alot of great old threads on the forums regarding the Jubilee. Look for posts from Bodcow Boy that would be Roy who worked with PWK on the Jubilee project.

I did as you recommended and those old threads are fascinating.

I also heard that Paul had a tough time making the motor board stiff enough to resist vibrations that would add resonance issues. I have a pair of clone built Jubilee bins that have a small resonance issue, but it hasn't kept me from enjoying my music. I am sure its a flaw of construction not design. I am leaning towards selling these and making the journey to the real thing, when I have the time and the money.

[Deang]

Mostly what Seti said. A very early prototype utilized a drone or passive radiator. I don't know at what point they abandoned the idea. Neither the patent or submission to the JAES makes mention of it. To the very best of my knowledge, there are no technical differences between what was published, what was built, and what is currently being built. Some aspects of the way it's being built may have changed, but it's the same horn. The same applies to the plans, whether clenched in the fist of Valerie Klipsch or rolled up in some drawer at Klipsch - rumors don't change the math. Finally, and nobody wants to hear this I'm sure - but Roy was largely responsible for designing the Jubilee LF horn. After the near final rendition was engineered and built, Roy went to tell PWK - at which point PWK said, "Show me the box". It's easy to forget that by that time PWK was pushing 90 and mostly deaf.

[Coytee]

Here's a picture of the original style with the wings inside as supports

[Coytee]

here is the newer design with 'shelves' in there as supports.

[bracurrie]

Mostly what Seti said. A very early prototype utilized a drone or passive radiator. I don't know at what point they abandoned the idea. Neither the patent or submission to the JAES makes mention of it. To the very best of my knowledge, there are no technical differences between what was published, what was built, and what is currently being built. Some aspects of the way it's being built may have changed, but it's the same horn. The same applies to the plans, whether clenched in the fist of Valerie Klipsch or rolled up in some drawer at Klipsch - rumors don't change the math. Finally, and nobody wants to hear this I'm sure - but Roy was largely responsible for designing the Jubilee LF horn. After the near final rendition was engineered and built, Roy went to tell PWK - at which point PWK said, "Show me the box". It's easy to forget that by that time PWK was pushing 90 and mostly deaf.

Thanks DeanG. Its great to hear this story. Pictures that appear later in the thread of the early cab and the later cab with shelves do add evidence to the changes made for ease of manufacturing the horn. Now the tough question. What did the early throat at the motor board look like initially and as modified later. What happens there would have an impact on performance, right? Even Bobcaw Boy's photo journalism didn't show that level of detail. Because it appears the plans are out there, it isn't a secret, or is it?

[Cornman]

I can only agree with one thing -- It sure does sound good!! []

[Coytee]

Here's a picture of one of the early/test units where they added some braces during (after?) initial construction. You can see them unpainted in the rear. I think what this helps illustrate is Klipsch (Roy) has continually tried to improve the bass horn. I don't know the what's or why's but it looks to me like this unit had some braces inside it. Later some unpainted braces were installed for whatever reasons and later on, they went to the shelves.

Personally, I like the LOOKS of the units with shelves. Looks "right" with them.

[Coytee]

Here's a nice picture of Dan's being made at the factory.

[bracurrie]

Here's a picture of one of the early/test units where they added some braces during (after?) initial construction. You can see them unpainted in the rear. I think what this helps illustrate is Klipsch (Roy) has continually tried to improve the bass horn. I don't know the what's or why's but it looks to me like this unit had some braces inside it. Later some unpainted braces were installed for whatever reasons and later on, they went to the shelves.

Personally, I like the LOOKS of the units with shelves. Looks "right" with them.

Those mods do not appear to be for improvements in construction. I wonder why they were put there. BTW isn't that the same speaker that appears with Paul where he is standing with the Jub to his right?

I agree about the shelves.

[Chris A]

Those mods do not appear to be for improvements in construction. I wonder why they were put there.

That's not hard to figure out--I'm sure that the extra stiffeners were put in to test their effect on bass bin acoustic performance in the Hope anechoic chamber. The fact that those extra stiffeners were later deleted in manufacturing says to me that they weren't a big improvement in the stiffness of the last folds of the horn.

What do you think? I'm sure that Roy could comment if he were still on this forum...unfortunately...

There is a down side to extra stiffeners: cost of the added material, added weight, cutting and assembly time/more parts, manufacturing tolerances of the stiffeners and side walls (the last folds of the horn need to be within 1/8 inch of drawing dimensions -- according to Roy), they take up volume in the horn, and they act as extra acoustic reflectors/diffusers inside the horn, which aren't desirable.

Chris

[colterphoto1]

Early on, when just a few of us had the Jubilee at home, I was working in Tech Support for Klipsch. When the calls and emails came in, I'd get them forwarded to Chuck Mulhearn for quotations or to Roy for technical questions. A bit later when you guys wanted them to be 'prettier' I discussed with Roy and the decision to make a veneered front panel came about. I dubbed it the 'beauty panel'. Those emails are lost to history but it was a pleasure being part of the early process of bringing these speakers to you guys.

[boom3]

idle question, what do a pair of Jubes run now? is the K402 + TAD the "standard" HF or is it a factory option, and if so, how much?

TIA

[Cornman]

The Tad's or extea $'s. W.C. at Panacea Engineering can quote you a great price, & is a true pleasure to work with.

Cornman