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Altec 605 + woofer in the same cabinet like Urei 813/5

A

Andresse

New Member
Hello
I'm planning to add a woofer (maybe Kef b139) to a 140 liters Altec 605 ported cabinet. My question is more about acoustic problems and how the wofer will affect the Altec 605 sound and of course if there is any solution except building separate cabinets.

I know that I must use Lpads since the difference between the drivers gain.

I would like to have your opinion

Thanks a lot
Andres
 
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I think you should consider a separate enclosure for the added woofer.

Are you familiar with the function of the 813/815 systems in that they are not a typical ported, bass reflex system rather an overstuffed box with a pressure bleed off as eluded to in the original Urei literature, and that the 604 and additional woofer/woofers are acoustically isolated by a damping shelf?

Also, consider that an 813 system uses a 325 liter enclosure, and 370L for the 815.
 
bowtie427ss said:
I think you should consider a separate enclosure for the added woofer.

Are you familiar with the function of the 813/815 systems in that they are not a typical ported, bass reflex system rather an overstuffed box with a pressure bleed off as eluded to in the original Urei literature, and that the 604 and additional woofer/woofers are acoustically isolated by a damping shelf?

Also, consider that an 813 system uses a 325 liter enclosure, and 370L for the 815.
Click to expand...

Thank you so much for your answer.
I'm not familiar with the Urei inner plan.
Is the damping shelf completely sealed and the woofers and 605 in completely separate boxes?
Andres
 
Andresse said:
Is the damping shelf completely sealed and the woofers and 605 in completely separate boxes?
Click to expand...
It's made of fiberglass that has been starched, or sprayed with some other substance to make it very rigid/stiff, very similar to the rigid fiberglass damping curtains used in the back chamber of larger Altec/Simplex theater horns.
 
bowtie427ss said:
It's made of fiberglass that has been starched, or sprayed with some other substance to make it very rigid/stiff, very similar to the rigid fiberglass damping curtains used in the back chamber of larger Altec/Simplex theater horns.
Click to expand...
Thank you a lot.
Is this shelf make a complete sealed separation between the elments?
Andres
 
I would call it a lossy separation. It's not rigidly affixed to the cabinet such that it will float, or be invisible at some frequencies and act as a near solid barrier at other frequencies.

The best illustration i could find:

attachment.php


Here's the complete thread where the photo was found:

http://www.audioheritage.org/vbulletin/showthread.php?26332-Urei-813B-Baffle-layout
 
b.jpeg The woofers will definitely couple together and is why Altec chose the 416B to complement the 604. Both use driver cones and magnets with similar properties. JBL did the same thing using their drivers when they bought Urei and continued to build Urei monitors. Altec made a 950 UHF ring radiator for the Japanese market to supplement different Altec full range horns and the 604 and 904 coaxes. The 950 uhf was a great ring radiator, that had a very smooth response and was very efficient with low distortion. I had to pull teeth to get 8 for a disco system we installed with an additional two for a long time customer who wanted to up grade his versions of Altec Carmels. The 950's were intended for the Japanese market only. Carmels use an 811B with an 806 driver, with two 414 12 inch woofers. There was also the Capistrano that used a 511 horn with a Single 803B woofer. I preferred the Carmels I owned in the early 60's. If I still had them I would be using the model 19 crossover to get a flat frequency response using the latest Great Plains diaphragm and 1200 HZ crossover.
 
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When JBL uses dual woofers in a single cabinet. They will run the first woofer from around 8oo hz on down and then add on the second woofer around 120 HZ or so for their previous monitors and top of the line consumer speakers. The JBL 4435 monitor and DD67000 consumer speakers.
 
You could use the Utah woofer. That's what they did for the Big Red Supers, though it was possibly/probably modified for the application.

Mine are from a recording studio and one-offs that are tri-amped with a custom made electronic crossover and passive eq units between the amp and horns. The Utah rolls off, first order from ~40Hz.

http://www.audioheritage.org/photopost/data//500/medium/DSC_00114.JPG

http://www.audioheritage.org/photopost/data//500/medium/DSC_00153.JPG

Feed to the horns:
http://www.audioheritage.org/photopost/data//500/medium/DSC_00046.JPG

Feed to the 604E2 Woofers:
http://www.audioheritage.org/photopost/data//500/medium/DSC_000310.JPG

Feed to the Utahs, (with no 50/75/150 Hz bass boost added):
http://www.audioheritage.org/photopost/data//500/medium/DSC_00028.JPG
 
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