Old Speaker Questions

[joyspring]

David:

The original UREI 800H horn (on the original 800-series UREIs) did not have the foam edges nor did it have the `shadow slots' as well. Have a closer look at the picture in DonR's post above.

It's simply a proper radial horn and is a vast improvement over the original stock Altec pseudo-multicells on the 604s.

I believe that the UREI loads a bit lower than the Altec though I've never measured either below 1 kHz; however, the fact that the UREI high-pass section is essentially single-order leads me to that conclusion. If so, the stock Altec horn may have uneven response for a couple octaves below the crossover point with the UREI network.

Note that even the UREI radial horn does not have the even power response of a constant-directivity horn, which is a very important criteria for large main control room monitors nowadays.

BobR

[joyspring]

Boltupright:

"If I had those I would make a nice 620 cab & find some 8G crossovers & use them for HI FI !!!"

While the 620 enclosures may be an improvement (the original 813 enclosures were designed exclusively for soffit quarter-space mounting), I would not recommend the original 604-8G crossovers (or any stock Altec 604 crossover for that matter).

Apart from the time-alignment properties, the UREI network flattened the frequency response overall and extended the (flat) HF response to 15 kHz.

The UREI network was the first to actually make the 604 an accurate reference (note I refrain from `good sounding' as that's rather subjective).

Lastly, the UREI 800H horns on the 604-8G may prevent the Altec crossover from producing a flat response below the crossover point, not that the Altec crossover would produce a proper flat response even with the stock Altec horn.

BobR

[joyspring]

Tom:

Yet another option for you may be to use the UREI 811 (single Altec 604-8G) network instead, and use a separate amplifier/enclosure and active electronic crossover (80-100hz) for the JBL 2234.

Here's the link to the UREI 811 docs:

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

The enclosure size for the 604-8G is not too critical (it's a sealed and won't be used below 80-100hz anyways) though staying about 5 ft^3 is probably recommended. UREI used a `pressure control aperture' which is simply an untuned port (nowdays, that's called aperiodic damping). This markedly improved LF damping and you may want to entertain doing something similar.

Now your options for the JBL 2234 open up immensely as enclosure parameters can now be considered independently of the 604-8G.

Best of luck whatever you decide to do,
BobR