Urei 813b project

[grumpy]

... a little late in the conversation, but

re DIY 604-8G horns, Yuichi has his A-800AL documented here:

http://www.geocities.jp/arai401204/D.../Download.html

[eso]

... a little late in the conversation, but

re DIY 604-8G horns, Yuichi has his A-800AL documented here:

http://www.geocities.jp/arai401204/D.../Download.html

Cool, he just put that up within the last 2 weeks. I had looked at his site for it and Emailed him and asked for the plans for it.

I may still build some of those. They are really pretty and based on my experience with building his 290Hz radial horns I'd be willing to bet he's done the math and designed a good sounding horn.

***edit***

So here's the page with the assembly and some graphs:

http://www.geocities.jp/arai401204/Horn/A800/A800.html

So, while he doesn't have 604 stock and modified measurements for comparison the Gauss rework looks like a substantial improvement.

And they're really pretty too...

Thanks for posting the link,
eso

[eso]

So here's the PAS CXS 1580 drivers fitted with the NOS Urei horns. Thanks to oldmics for the horns...



Now I just have to order the crossover parts. I think I'm going to build completely stock for starters, and then try to upgrade by charge coupling the the portions that affect the coax. The parts count gets crazy when I quadruple the caps for the CC circuit, and I've already spent a little bit on the effort...

AS a side note, I was doing some patterns today for the Yuichi 800Hz horn for the 604 8G...


The geometry of this horn nearly Identical to the horn for the Urei 809 12" coax. The Yuichi horn is a more refined radial design. I'm going to throw a pair together as I think his designs are well executed and worthy of exploration.

Still, I'm moving ahead with the basic 813B set-up with 840 crossover first: start with a known quantity before moving the goal posts.

eso

[eso]

Does anyone have a drawing of the 813B cabinet Baffle layout? Or can someone measure theirs and post that information?

It should be 36" X 31", but I need to location of the driver cutouts and the size and location of the vent/crossover openings.

Any help would be appreciated.

eso

[Bob Womack]

Hi, ESO!

I pulled out a ruler and went to work on our UREI 813B/Cs. Because of our particular setup, the speakers are oriented with the bass driver on the top and main driver below, near ear level. The port is next to the bass driver and the control panel is next to the main driver. These monitors were furnished with left and right mirror image cabinets. Basically that means that the port and panel are set together on opposite sides for the left and right speakers.


This is the right-hand speaker in the soffit.

Here are the dimensions I got:

Port - 2" down, 1" from edge, 7.5" tall x 4.75" wide

Edge of bass driver basket flange is 2/75" from top edge and centered left/right

Edge of main driver basket flange is 2.25" from bottom edge and centered left/right

Crossover control panel is 1.5" up from bottom, .75" from edge, on same side as the port.

We power ours with a Hafler TransNova P7000 amplifier and use Klark-Teknik DN360 graphic EQs to smooth them out. All that is mounted in the machine room. We've tuned them with white and pink noise and we've shot Fast Fourier Transforms of the room. The speakers are inserted into boxes built with two layers of 3/4" plywood that are mounted to steel posts. We cut through the foundation of the building and poured separate footings with bolts to secure the posts. After that, floating floors were installed and the room's shell built around, but not in contact with, the existing speaker mount assemblies. As a result, the speakers are totally isolated from the structure of the room.

The control room is an unlicensed Live-End dead-End room, designed by an engineer who studied at Syn-Aud-Con. The front end is as anechoic as possible and shaped to pass all residual reflections to the back wall.



The acoustically-significant portions of the rear walls have been treated with RPG diffusers. We sent the blueprints for the facility to Dr. Peter D'Antonio at RPG and he designed diffusers to the space. Here is a shot of the rear:



I'm reproducing this info on the forum so others can benefit. I hope that helps a bit in your quest!

Bob

[mikeharris]

i have a set of new old stock 813 crossovers we discover while cleaning up

[UreiCollector]

Have you made any progress with the 813's?

[eso]

Have you made any progress with the 813's?

I have to get the parts and build the crossovers. I've got all of the drivers for the 813b, and the cabinet layout, but beyond collecting the various parts and info I have been too busy finishing up a project for my work to take the time in my shop to complete them.

Oh, and I've got a local foundry casting some of the PAS heatsink/compression driver mounts for some other 15" drivers I came up with too.

Soon I'll have a completed pair.

eso

[eso]

It's been a while since I've posted here. The end of last year nearly worked me to death and I've been getting another project underway for this year.

So, I am only now getting back to my Urei project. Here is a prototype for a wooden horn that I reverse engineered from one of the originals I got from Oldmics. These are made from a plywood I laminated using 7 layers of Wenge veneer. The idea is to use an industrial wool felt for the mouth instead of the foam:







These are coming out nice enough that I think I'll use some of the really nice veneers I have for a deluxe pair after I sort out the the throat construction.

I still haven't got the heatsinks back from the foundry and I have yet to get the crossovers under way.

So, I'm still plugging away with them, just much more slowly than I'd like!

Eric

[rgwalker]

It's been a while since I've posted here. The end of last year nearly worked me to death and I've been getting another project underway for this year.

I still haven't got the heatsinks back from the foundry and I have yet to get the crossovers under way.

So, I'm still plugging away with them, just much more slowly than I'd like!

Eric

I have a pair of crossovers from Urei 813s that I should sell. I never got around to building the project they were for and likely never will. If you're interested I'll send you photos. If you're planning to duplicate the system with the light boxes it's something to consider.

Bob Walker
[email protected]

[eso]

Well, I've gone from just trying to recreate a pair of Urei 813Bs to trying to recreate the drivers with some improvements.

Since PAS has long since stopped making the cast aluminum heat sink/compression driver mount of the original B series drivers I decided to talk to an old friend that runs a foundry....

Here's the first test castings. These are sand castings as opposed to the originals which were die cast. These will have the mating surfaces and screw and mounting holes milled and then be painted. Not as clean as the originals, but the whole thing is just lipstick anyway...



I have parts for 3 pairs of these, and once I complete the throats for the little wooden horns I should be able to put together a really nice set for a domestic setting.


eso

[Mr. Widget]

Not as clean as the originals, but the whole thing is just lipstick anyway...

Glad you said it first.

Looks good though. I like to see a pretty girl wearing the right shade of lipstick.


Widget

[eso]

Well, here's an 813B...



I just roughed everything together to get a look at it before paint. These have to be one of the ugliest boxes ever conceived.

Once completed I'll probably fly these somewhere in the shop. The crossovers are the wrong model, but I got them to use as an example for circuit/wiring layout and panel sizes.

Have any of you ever run Urei monitors with the Urei 6500 amp using their "Conductor Compensation™" circuit? I'm very curious about what it is and what it does.

eso

[mikeharris]

the 6500 was a great match for the 813

[UreiCollector]

Well, here's an 813B...

eso

These look great! Can't wait to see them with paint! I have used Duratex on some recent projects, and it would look great on these!