University Classic vs the Jubilee (?)

[karlson3]

hornresp says they're ~ "equivalent" - a thermal edge for 2xK31 in parallel vs 1 K33

 

it might be difficult to get  ~0.5 pi with the boxy Classic (?)  other than the throat

the Classic should be the easier build.

 

 

sims:

 

https://i.imgur.com/4kioQCs.jpg

 

[karlson3]

and here's what a K33 in a Karlson box the size of the classic K15 Karlson might do vs the Jubilee in 0.5pi  In practice, I would use a 15 with higher midrange sensitivity than K33 spec in the Karlson

 

https://i.imgur.com/3sDBQ14.jpg

 

and a rough guesstimate of a K15 size Karlson in 0.5pi vs the Jubilee at one watt

  

 

 

[garyrc]

I know very little about this, but I have to ask, are the Karlsons you refer to these Karlsons?  I think we talked about this a bit before.  Do you have any data on the Karlson v.s. the JBL C34?

 

 

Does the 15 in K15 designate a Karlson box designed for a 15" speaker?

[karlson3]

Yes - I don't have a model for the C34 - was that a back loaded short-path horn cabinet close in details to a JBL 4530?   I don't know if I'm modeling the 4530 correctly as has a deep hole around 165Hz, but its sensitivity with a JBL M151 shows higher than the Karlson and higher than the Jubilee

 

"K15" is what I call the original Karlson cabinet, which was developed in the summer of 1951 and made its debut in the fall of 1952 at the New York Hi-fi show.  Its construction details were published in the January 1954 issue of Radio and Television News

 

 

[garyrc]

5 hours ago, karlson3 said:

Yes - I don't have a model for the C34 - was that a back loaded short-path horn cabinet close in details to a JBL 4530?   I don't know if I'm modeling the 4530 correctly as has a deep hole around 165Hz, but its sensitivity with a JBL M151 shows higher than the Karlson and higher than the Jubilee

 

The JBL C34 was, in some ways, similar to the JBL 4530 of those days (they evidently recycled the number, of all things!).   The C34, also a rear loaded horn, was larger, and accommodated only a 15" woofer, and was cut to fit in a corner..

Here it is, with a JBL 030 system I used to have, a D130 15" extended range and an 075 "bullet" or "orange juice squeezer" tweeter.

 

 

This, on the other hand is the JBL 4530; it was thinner, but possibly taller.

 

At the Hi Fi Fair (c.1960) I told a JBL tech I had the O30 system described above in a Karlson.  He said, "I wouldn't.  You probably have a big peak at about 100 c.p.s. (as they called Hz then)."  He recommended a C34.  So, when I converted to stereo, I had a Karlson on the left and a C34 on the right, with identical speakers installed.   I had ample time (~~2years) to compare them; I did so endlessly, with my Dyna PAS 3 preamp set on A+B, rotating the balance control from full left to full right, over and over again.  I had OCD even then.  Here is my impression: C34 a bit smoother, Karlson "punchier."   An example would be the old Mercury version of 1812.  The cannon was significantly boomier and more frightening with the Karlson.  OTOH, any of the Beethoven symphonies in the Readers' Digest set ( Rene' Leibowitz / Royal Philharmonic) sounded more effortless and real with the C34 than with the Karlson.

 

I was hoping you had some curves on the C34, so I could compare it to your curves on the Karlson -- just a matter of curiosity.

 

Neither system sounded nearly as good to me as my AK4 Klipschorns.

[karlson3]

I'll ask someone for C34 curves and see what he says

[karlson3]

hi  garyrc- so far no luck with a C34 curve but here's that type, a C40 with JBL 2226 from RCA-Fan - that's a lot of "hit"

 

 

 

[garyrc]

That's informative.  I think the C34 and C40 were very internally similar, except that the C34 was larger.  That the C34 was intended for corner placement may have have helped, at least for those who put their C34s in corners.  Thanks for the info.  

[ClaudeJ1]

My current Jubilees, with twin 12" drivers (equivalent to an 18" driver) and 8 db of EQ at 32 Hz. Have useable response in my room down in the high 20's. Real vs. theoretical output  says the Jubes WIN.

[karlson3]

how far down do you think a Classic would be in comparison at 30Hz?

 

FWIW here's what a sim says about 2 K31 in an 80 liter sealed box (same size as Jubilee's back chamber) vs how they do in the Jubilee

 

[ClaudeJ1]

9 hours ago, karlson3 said:

how far down do you think a Classic would be in comparison at 30Hz?

 

FWIW here's what a sim says about 2 K31 in an 80 liter sealed box (same size as Jubilee's back chamber) vs how they do in the Jubilee

While your simulations are essentially correct, I can attest to how great they sound in actual USE.  For a small living room, Roy Delgado (Klipsch's Chief Engineer and co-designer of the Jubilee) came up with a 32 Hz. boost for Active Digital Xovers that works very well below horn cutoff, negating the requirement of subwoofers for 99% of music. In practice, this means I use 4 Watts of power instead of 50 Milliwatts at 85-90 db listening at me sweet spot. So regardless of which type of horn you use, horn bass still puts the listener way ahead of the game with low distortion and  sonic impact via superior transient response. I should add that I have also currently own or have owned Danley DTS-10's, DTS-20's, TH-50's, Fitzmaurice Tuba HT's, and various other horn subs, but in my new digs with small rooms, good enough is good enough without those Sub Beasts!! Now downstairs in my HT room, that's a different world and subterranean subs are part of the sound effects, and not necessarily for music, although they don't hurt a bit on Blue Ray concert videos OR movies!! LOL.

[Marvel]

For sure the Classics would be an easier build. I would love a pair. If I had any kind of workshop I would have a go at a pair. After seeing what nico boom did with his I'm even more inclined.

 

Bruce

[karlson3]

re: University Classic  -   I like the stock look but Nico did  fine job and the plexi access panel nice.  (In my scaled UC with a 10", there's a bunch of triangular foam blocks to reduce the back chamber size)      RCA-Fan (Bill Woods) made an interesting comment  concerning the cavity formed by the throat pieces and cabinet's sides   "If this cavity is left open, it will act as a mechanical notch filter, creating a hole probably around 500Hz."      

 

so it might be a good idea to make a cover for that area 

[Marvel]

Can you show/mark up a pic to show me where you mean? I'm not quite following you. Do you mean the area under the cab that nico boom cut away (which made the cabinet look smaller)?

 

Bruce

[karlson3]

Yep Marvel -  here's my (loud) toy 0.7 scale Classic to illustrate - At ~0.7  it came out a wee bit too small for a 12" to fit.  Another inch of depth and it would be good to go with something like a 12pe32.  The low Q 10" I have in it is lively.     A scaled Classic for 12 with good sub would make an interesting project.

 

fwiw - here's a sim of the Baby Classic with a 10" SWR/Eminence and 10 liters back chamber vs a Belle with K33.   To be fair, I think this SWR is probably more like a "6 ohm" driver 

 

 

[Marvel]

Thanks for that. I wonder if it made a difference on nico boom's he cut all the bottom from. There is still a cavity underneath on his. He runs his up to about 1000Hz before crossing over to the 2 inch.

 

Bruce

[karlson3]

good question  -  with sides open around Nico's throat -"stand",  resonance Q would be greatly reduced - might not be any noticeable effects .  On a regular Classic it would be easy to make a snap-in cover to block that cavity - and to some, the looks might improve.  (I like seeing the compound angle throat pieces)

 

I think doing it Nico's way from scratch might make it a tiny bit easy to build

 

 

 

would it look worse if there were a bottom trim piece ?

 

[Marvel]

Some trim might look fine but just more work. Other than the compound angles on the throat, the rest looks pretty easy. I don't have any kind of workshop, but would love to build a pair of these. I would not have the plexi on the woofer cover, so is would be easier still. His came out looking awesome, though. Very stunning in execution.

 

They would be much easier to build compared to Jubilees and I like the idea of a non bifurcated mouth.

 

Bruce

[karlson3]

I've got an idea - if set up like Nico's speakers - you might ask Jesse Brunner (Triticum Audio) for a quote to make a pair of just the throats - those could be sent relatively cheap to ship from Washington vs completed cabinets.  It might not be too difficult to build & fit the rest of the cabinets around the throat section (?)

 

Like so - have Jesse build that compound angle throat including the speaker baffle - in my case I'd ask also for the two pieces which complete the back chamber - maybe the end which connects to those tapered "ramps".  Brunner does world class work cheaper than I could get done by a cabinet shop.

 

[Marvel]

My older son has become a good woodworker. I'm going to ask him about constructing the throats for me. He's only five or six hours away from me. I was just dropping the wife off for an overnight shift and thinking on the way home that if someone were set up to make that difficult part, they could probably be sold to folks who wanted to build these.

 

That's Dennis' corrected drawing isn't it?

 

Bruce