altec 9846-8A

[LICORNE]

Hi,

Congratulations on your new Altec. If these sound as great as the 9845 which I sat through several live recording sessions in the seventies you got a winner.

The horn is a 511 with a XO at 500 . With the upgrades you should not hear the cow bell sound.

http://www.lansingheritage.org/image...-8a/page04.jpg

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[Old Guy]

Originally posted by grasshopper:
. You are definately right- it is more of a 'rebuild' rather than a 'revive'. I'm knee deep in the first pairs' cabinet rebuild. I'm keeping everything to original specs (internal dimensions, etc) but I'm just making the cabs thicker and more inert. The new cabs will be maple veneered with maple 1/4 round edges. Also- new crossover components (again same original specs- just new components). New terminals, etc...

The only gripes I have with the original design is that it doesn't handle much power. Granted they were never intended to. The old cabinets easily flex and color the sound too much. Also, that 811-B horn starts to ring out like a church bell when things begin moving around in there. That's really the only MAJOR flaw in my opinion. The drivers, however, seem more than capable of extra juice.

My goal is to make a few careful conservative tweaks without destroying the wonderful relationship the drivers have. I hope it works. If not- I can always throw it back into the old cab/crossover combo and just turn the volume down a bit. They are lovely for home theater and never fatigue my ears.

Sorry if I came off sounding like an *** - not my intention. Also, sorry to hijack the thread. I'm just a bit enthusiastic about them...

<font size="2" face="Verdana, Helvetica, sans-serif">No problem. I was just curious. I have seen people do things like adhesive and sand mixtures and paint the outside of the aluminum horns. Making the cabs double layer like you are doing should also help.

Biamping can make a wonderous difference....

[intotubes]

Also, I would turn them around. The 9844 monitors were made for ceiling mount (near as I can tell) with the HF horn on the bottom. If I were building new cabs I would go for Malibu's with the 2 12" woofers on top of each other and the horn more at ear level. I almost did that to my Carmels but ended up stacking them on top of my Cornwalls instead.

[grasshopper]

The advice is great- all of it. I really appreciate it. I moved this to another thread found here:

http://www.hostboard.com/cgi-bin/ult...&f=3729&t=2371

[Russ Farrell]

Hi Grasshopper:
Old Guy's suggestions on damping the 811 (and trying biamping) are good. Another damping method in the old days was to put autobody undercoating from spray cans on the outside of the horn from the horn mounting flange to the driver mounting flange. Several people told me that also putting it on the outside of the bell in front of the horn flange didn't seem to improve it. The drawback is that stuff is messy, and if for some reason you change your mind it was a bear to remove.

Altec's engineering managers said the 511 and 811 horns wouldn't ring with small format drivers, because even at maximum spl the drivers couldn't put out anywhere near enough acoustic energy to exite the large mass of the horns. Sounded logical to me. (That ringing I thought I was hearing must have been coming from somewhere else!) The large format horns did put out enough energy, which is why the 511E horns for 1.4" drivers were dampened with some industrial type gunk similar to undercoating. I forget the name of it, but supposedly it wasn't readily available in quarts or gallons for consumers.

The 9844 worked very well in small churches, meeting rooms, etc where it often was mounted flush on the wall near the ceiling. With the horn on the bottom, the two woofers and the horn interacted in such a way that the maximum acoustic output was tilted down instead of straight ahead. A good thing in a too-live room: more direct sound and less reflected sound. We used the 9844 as our main demo room speaker at the Altec contractor I worked for. Listening to music through it always brought a smile to my face. Good luck with your project.

Russ