Urei 604G crossover options

[Elitopus1]

So I finally found another non tangerine Urei 604G to match my single. It seems like most of them were later 604G with the tangerine. So now that I have a pair of them I want to get some crossovers going.

The first option is the crossovers Urei put in the 811. That was the single driver studio monitor. Just a 604G in each. I have a schematic for the xover. The thing that bugs me is these speakers were only rated at 87db @ 1 meter. Is all the sensitivity lost in the crossover? The 604G is 100db @4ft in a 620a cab.

Another option is buiding some crossovers from Jeff Markwarts plans. He offers one for the regular 604G. I have spoken to him about those. He said he did not do any testing on the Urei version of this driver. He thinks his crossover would probably still work ok.

One more option is to biamp them with my Ashly amps with built in xovers. The question is whether to just use the active crossovers and just forget about all the expensive passive components

I am planning on powering the drivers with the Ashly amps regardless. Maybe I shouldn't care if the Urei xover knocks down the sensitivity



Urei 828 Xover

[GM]

??? Where did you get 87 dB/W/m? Their brochure lists it as 99 dB/W/m, a far more reasonable rating: http://www.lansingheritage.org/images/jbl/specs/pro-speakers/1984-urei-81xB/page2.jpg

WRT to XO choice, since you can, twist/slide your way with digital and fine tune as much as you can to 'taste', then look at just doing the HF passive and better still, couple it to a flea power SET to boot since the pioneers developed them together as a system for the best performance Bell Lab's/W.E.'s 'deep pockets could afford, i.e. basically cost no object, so who are we to second guess them and why there's been precious little improvements over the decades other than via materials, manufacturing advancements.

GM

[Elitopus1]

??? Where did you get 87 dB/W/m? Their brochure lists it as 99 dB/W/m, a far more reasonable rating: http://www.lansingheritage.org/images/jbl/specs/pro-speakers/1984-urei-81xB/page2.jpg

WRT to XO choice, since you can, twist/slide your way with digital and fine tune as much as you can to 'taste', then look at just doing the HF passive and better still, couple it to a flea power SET to boot since the pioneers developed them together as a system for the best performance Bell Lab's/W.E.'s 'deep pockets could afford, i.e. basically cost no object, so who are we to second guess them and why there's been precious little improvements over the decades other than via materials, manufacturing advancements.

GM

I was researching it and found this link to the Urei 811 spec sheet. Its also where I got the xover schematic.

It probably is good to play with the xover point first electronically before deciding on a passive setup. Thanks

http://www.jblproservice.com/pdf/Vin...s/UREI-811.pdf

- - - Updated - - -

The link you posted shows the "B" version. I believe only the "A" version had the Altec 604G driver

[GM]

True that the B had a custom driver, but it's mostly a clone performance wise. Regardless, to drop a 604 down to 87 Hz would require flattening it to below Fs, so has to be a typo. IIRC, to flatten a 515/604 to Fs in half space still gets you 95-96 dB/W/m.

GM

[Elitopus1]

Ok thats good to know. One of the things I love about Altecs, and horns, is their high efficiency. It makes the music much more dynamic.

I am on the lookout for a pair of used Urei crossovers. Until I find some, or build some, I will use an active crossover.

I am planning on playing with the speakers for a while and then sending them to GPA for a remag and recone. They have slightly different cones, even though both are versions of the 35400 replacement cones.

[GM]

Unless it's got plenty of adjustment, I personally wouldn't bother as studio monitors are set up for mixing in a very controlled acoustic environment, not a HIFI reproduction of it.

GM

[Elitopus1]

I'm treating these the same as I would a pair of regular 604G. They will be used for HiFi. Bill has said when I get them reconed he could change the horns for me to the regular egg crate style if I want. I just have to listen to the Urei horns for a while and see if I like them

[Elitopus1]

My other question is what to do with the crossover holes in the front of my model 17 cabs. I got them with no crossovers. If I decide to use something else than the n604-8a crossover how should I fill these holes?

I have some old n801-8a crossover front pieces I am not using. Of course then I would have a pot on the front of the speaker that isnt even hooked up. And I would have binding posts up there too.

I am interested in the GPA n604-8b xovers but the attenuation plate looks to be a different size than the hole in my cabs

[GM]

Anyway you want to just as long as they don't leak, move, i.e. duct tape ain't gonna cut it unless several layers thick. .

GM