Two-way speaker system, WAY horn-loaded

So T, after a bit of listening, how do the JBLs compare to the Altecs??? I just got back from FL last night after a week of being gone and the first thing I did, after kissing the wife, was fire up the Imperials. Damn I missed them. The bass on Hotel California from the Eagle's live album makes dust fall from the ceiling. To bad these things are so big, I'd like to A/B the JBL 136A I am using with all the drivers you've used.
 
So T, after a bit of listening, how do the JBLs compare to the Altecs???

Yesterday I bought Dave Newman's JBL L15B's, the nice pair that measure close to each and reasonably close to spec. (And Dave Newman is a NICE SMART GUY, and a good guy to deal with!) With help from Ron (spkrman57) and Brad while I marinated skewered and grilled some kebabs, we got this matched pair installed in the Imperials and made a quick'n'dirty adjust on the inductor value for the 2nd order crossover. (Ron came up with some rationale for keeping the cap value the same, tossing out a lot of Butterworth and Linkwitz-Reilly to confuse us). Top end was still JBL 2441 and constant directivity horn on a 3' wide baffle.

Oh, and while I had more hands to help carry heavy things up and down stairs, we put the deHavilland Aries amps in the living room system (less efficient, could use a few more watts for overhead), and put Larry Moore's UltraFi Monaco on the Imperials. Got it all hooked up, left it playing quietly, ate dinner... returned to the scene.

By this time the Ultraverve preamp and the Ultrafi had time to warm up. Tracks 4 & 10 of Flight of the Cosmic Hippo confirmed that we HAVE solid horn loading into the 30s. :thmbsp: Some reference classical material to dial in the Lpad for the top end, and after that it was ALL GOOD. We put on lots of different kinds of music...

:banana: :banana: :banana: :banana: :banana:

Ron and Brad agreed: this system KICKS ASS.
 
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Rick,

It was a pleasure talking to you and dealing with you, as well. Very glad to hear they worked out so well.
 
It was great meeting a few folks at the fest Saturday.

I actually made it a more involved weekend by visiting and staying with Rick and Brad and checking out their audio gear.

I have to admit that Rick's Jensen Imperial horns are impressive in size when you actually stand in front of them, and they sound as impressively big as they look!!!

Ron
 
But they just didn't load the horn, at all, and the bass just wasn't there. Maybe the Fs at 40 was too high... but I think the horn DID work with at least one other driver (EV) that had an Fs at least that high... so it might not be a single-parameter answer.

I think you have the answer there. Something like a 130A/2220, the aforementioned 2205s (or the more modern equivalent 2225), a 2234. or an LE15 variant would probably be right-on. A bit more cone and voice coil mass than the E130 (which, IMHO, is a big midrange driver, in essence... great for lead guitar, but nothing for bass).

The EV, while having a higher Fs, also probably had a slightly higher Qts too, IIRC. More cone mass on the DL15... not excessive, but enough.

One idea- if you ever have the E130 back in there... try putting a 1 ohm resistor in series. It'd be interesting to see if reducing the damping a bit might "pump up" the bottom end a bit...

Regards,
Gordon.
 
Something like a 130A/2220, the aforementioned 2205s (or the more modern equivalent 2225), a 2234. or an LE15 variant would probably be right-on.

Altec 515E worked well, old Tannoys worked well, but I don't think I'll be trying any more after getting JBL LE15B's in there. With measured specs for these particular units giving Qts well under .2 and Fs around 25, it's no surprise that they work really well.

One of these days I'll do a real sweep with sine waves, but performance with music is all I need. What always amazes and amuses is that even with very high LF SPL's, cone excursion is BARELY noticeable. It just doesn't get sloppy or compressed when the going gets loud.

I think 25" wide wood horns might be JUST THE THING to put the top end where the bottom end is. These are going in next:

524213902_rDgox-M.jpg
 
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I need a bigger living room apparantly!

Yeah, well, me too. These refrigerator-sized plywood-&-primer beasts wouldn't work in my living room either, but I can do goofy things like this in my guy-space in the basement. That area is currently unfinished (concrete floor, naked rafters, painted cinderblock walls) and crammed full of stuff (which probably helps the sonics by breaking up waves), but I have a serious intent to empty it out, get two 20A circuits' worth of wiring in place, panel the walls, civilize the floor and ceiling... and make it a nice place to visit, listen to music, maybe set up a projector and screen for big movie watching.
 
... I need a bigger living room apparantly!

I have a bigger living room and a VERY understanding wife. After hearing the '52 Imperials in Rick's basement again I've decided to build a pair myself.

It does KICK ASS - seriously impressive.

I'm hoping to design them so I may (somewhat) easily modify the compression chamber by allowing relatively easy access via the top and front baffle area. Initially, I'll start with the same compression chamber and my LE15B's and a Great Plains Audio 399 for a compression driver. I'm glad to have this thread and Rick's knowledge ahead of me. It would be VERY difficult otherwise. As is, I can imagine some fun in constricting/opening that throat and trying some other drivers as well.

I've decided to use 3/4" Birch plywood for the build but first I'll mock one up with 3/4 insulation sheathing to work out some bugs.

Brad
 
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I can't wait for Brad to build his Jensen's so I can see how they turn out.

I have a small house, but still dreaming about a pair in the future.

Regards, Ron
 
First trial of Yuichi A290 in a two-way

ALMOST DONE with the first one :D

Very cool, Brad! You're doing great work there.

I got the adaptors drilled and the drivers mounted on the Yuichi A290 wood horns a couple nights ago, and last night I put them on top of JBL 3677 cabs with 2226 just to try them out.

530980891_75nBf-L.jpg


I hooked them up with crossovers that are basically the Four Pi design but with a 100w L-pad. Still got some phase issues with driver placement, but sounding very promising. I stayed up much too late just listening... Initial sense is that vertical dispersion is noticeably limited, so they should be reasonably close to ear height, but horizontal dispersion is really wonderful if you want a whole couchful of top-notch listening... The quality of the sound makes me think these will be a good match for the Jensen Imperial cabinets.

530980966_wbzaA-M.jpg
 
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Must be using woofers with neodymium magnets....

Ha!

Kind of like John Candy trying to sell the shower curtain rings off as earrings in the movie Planes, Trains and Automobiles

"They are filled with Helium, so they are very light...."

I guess you had to be there :D

RC
 
Looks to be a much more lightweight version than the original ;)

RC
Polystyrene speakers are all rage these days.

The pink mock-up cost me less than $30. Considering my relative inexperience and the less than detailed '52 plans, it was money very well spent. I have a level of knowledge and confidence I wouldn't have had without that seemingly silly experience.

I just returned from Toledo Plywood where I purchased 8 sheets of 5x5 Baltic Birch. They did most of the cutting as well for cost of just under $290.00.

My brother has the tools and experience to help with cutting the tricky angles which he and I will get cut tomorrow. I expect to begin gluing and nailing tomorrow as well.

Very exciting!
 
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Polystyrene speakers are all rage these days.

The pink mock-up cost me less than $30. Considering my relative inexperience and the less than detailed '52 plans, it was money very well spent. I have a level of knowledge and confidence I wouldn't have had without that seemingly silly experience.

I just returned from Toledo Plywood where I purchase 8 sheets of 5x5 Baltic Birch. They did most of the cutting as well for cost of just under $290.00.

My brother has the tools and experience to help with cutting the tricky angles which he and I will get cut tomorrow. I expect to begin gluing and nailing tomorrow as well.

Very exciting!


It is indeed Brad, and also a slick way of doing a mock-up :thmbsp:

Nice to work the bugs out of the project and not waste material because of miss-cuts. Dang good idea.

RC
 
A Sturdier version

Woo Hoo

And a week later I finally have a wood version. Baltic Birch to be exact. Not perfect woodworking but I'm pretty happy with how they are coming along.

Lots to do before they are living room ready but it's on the way.
 

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