604 in a A7 enclosure anyone?

[Steve Schell]

Altec fitted a 604 to a combination enclosure somewhat larger than an 825 box as early as 1945, but the model was short lived. This model A6 is described in the first Voice of the Theatre catalog.
http://www.voiceofthetheatre.com/ima...att1945.10.jpg

[bowtie427ss]

Wow, this has me confused. What is so bad about the LF driver of the 604? And what are the better bass drivers that are available? I don't remember seeing that there.

<font size="2" face="Verdana, Helvetica, sans-serif">My understanding is pretty basic here, but i think the issue is not so much the LF ability of the 604, as it is the high XO dictated by the size/cutoff of the HF horn.

I've just gone thru this first hand trying to model a box for a duplex very similar to the 604. The driver i'm using is capable of flat 30 hz response in the proper size and tuned box. Unfortunately, if i try to put this driver in that box, then it's response becomes like OG's roller coaster. The driver uses the Urei style HF horn and the ideal XO is 1.6k. What i have learned about duplex's thus far is that the limitations mostly seem to revolve around the XO point, which in my understanding cannot be shifted much.

[LICORNE]

Stanley Screamers had 2 604 HPLN in what seems to be an 817 cabinet. If it worked for them who knows.

http://www.lansingheritage.org/image...mer/page02.jpg


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[bowtie427ss]

Stanley Screamers had 2 604 HPLN in what seems to be an 817 cabinet. If it worked for them who knows

<font size="2" face="Verdana, Helvetica, sans-serif">Please note that they advertise the cabinet as TRI-AMP ready MID RANGE COMPONENT NOT INCLUDED.

That would certainly address the high XO of a "normally" used duplex.

But at the same time isn't that defeating the point source qualities of the duplex drivers?

[LICORNE]

In reading the description of the Stanley Screamers. I noticed mid frequency component should be added. In this configuration A mid Mantaray horn is needed . They seem to recommend tri amping in a front loaded horn such as the 817. It makes a lot of sonic sense.

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[bowtie427ss]

They seem to recommend tri amping in a front loaded horn such as the 817. It makes a lot of sonic sense.

<font size="2" face="Verdana, Helvetica, sans-serif">I had always assumed the 604 HPLN used some sort of hi power HF diaphram. I fully expected to find the HF bandwidth would fall off sharply from the use of a symbiotik diaphram, but it appears they used the HF section of the 604 more as a high output tweeter. And, since it looks like they used 290/291's for mid drivers, wouldn't that have allowed much more flexibility to use the 604's LF cone as a woofer?

I think this makes it safe to say that they successfully used 604's in a horn box, but NOT as the full range driver it was originally intended to be?

[LICORNE]

I agree HPLN like in 515 8GHP high power woofer.

These systems were designed for touring Rock concerts.

As bowtie427ss
Senior Hostboard Quoted.

I think this makes it safe to say that they successfully used 604's in a horn box, but NOT as the full range driver it was originally intended to be?

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[bowtie427ss]

OK i'm gonna go way out on a limb and share a thought during it's conception.

What i'm thinking is a 3 way, all altec loaded A7-500. I've seen multiple posts here from A7 users not happy with the HF extension of their big altec horns and drivers, with the remedy more often than not being the addition of a tweeter.

I suggest that instead of adding the 2405 or t-35/350, which i find objectionable asthetically, and it crosses my boundaries of "brand loyalty within the system", lets load the A7 with a 604 using it's HF as a tweeter much as the above mentioned Stanley Screamers did.

I've always thought that no matter where you locate an additional tweeter on a VOTT, it always looks "cobbed" and like it doesn't belong there. Seems to me that using 604's HF as a tweeter would also address any time allignment issues otherwise caused by locating the tweeter at or near the cabinet's front.

What am i overlooking here?

[Old Guy]

The 604 HPLN cone looked like a 421 cone. Don't know that it was, but the resemblance was striking. I had them side by side.

I used to use systems with the 3 way setup, I didn't care for them. The major problem was that Altec had never brought out a decent tweeter.

There is a phenomenon know as horn ratio distortion. It occurs when a horn is used over a wide bandwidth. I'm not a designer, and not pretending to be, but in the old days limits were placed on the bandwith horns reproduced.

What I would like to see is a 12" version of the 604, and using a seperate sub. You could have point source imaging in the areas where it matters most, and low end response to boot.

[smallpond]

Please list the 604s sonic tradeoffs as you see them.