8-ohm components for A8 VOT

[Jon A.]

Hi all:

This is my first post, as I recently got the bug to build my own Altec-type speakers.

All the A8 data I've seen is for 16-ohms.

What components would be advisable for 8-ohm home hi-fi listening?

I have 2 30623 bent horns (no drivers) won off eBay, but that's it .

One more issue-

I've seen two sets of plans, one with 2 round reflex ports and the other with the older slit port. Which is better for bass?

Thanks,

Jon Archibald
Peterborough, Ontario

[Fitts]

Hi, If I am not mistaken, you want a pair of Altec 416 woofers for your A8 cabinets. The impedance of 16 ohms versus 8 ohms does not change the cabinet construction. An 8 ohm 416 woofer will function just the same as its 16 ohm counterpart in the A8 cabinet.

Basically, it is not essential to have 8 ohm equipment for home listening. What does matter is that the impedance of the horn driver and the woofer are the same and that both match the crossover. If you have 8 ohm horn drivers, you should have 8 ohm speakers and 8 ohm crossovers. The same would be true for 16 ohm systems, 16 ohm horn drivers go with 16 ohm woofers and 16 ohm crossovers.

As far as the choice of round ports or the long slit, I would go for the long slit cabinet. If I am not mistaken, the round tubes have to be custom tuned for the best response, making the slit port is a lot easier.

I hope this is helpful.

Regards,

[GM]

Unless you get lucky, for optimum performance the vent will need to be tuned. Tubes can be partially inserted with putty around them to seal them, and once the correct length is found, glued in.

With a slot cut in a baffle, all you can do is start with one too large and clamp another board over it, varying the opening to find the optimum area, then do whatever is necessary to make it look nice.

Performance wise, the high aspect ratio slot is somewhat resistive, making it a bit more tolerant of less than optimum alignments, so I guess which type is chosen depends on the degree of accuracy desired.

GM

[aeyb701]

Hi again:

Re A8's-
I've got the cabinets constructed but I need to know whether the flange of the 416-8b should be mounted externally or internally. i.e. flush mounted, or recessed as I've seen in some OEM ad photos. The 32b/802-8g will me mounted flush, i.e. from the outside surface.

Thanks,
Jon Archibald, Indian River, Ontario

[LICORNE]

Hi,

The 416-8B is mounted from inside the cabinet.

http://www.lansingheritage.org/image...vott/page6.jpg

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[gamalot]

The 416-8B woofer was designed to be mounted either or, front or back of the baffle. Model 19s have them front mounted while others like them from the back. The 416-8As are designed to be mounted from the rear and are pretty tuff to mount on the front side due to the casting ribs.

Think I would search fro a pair of 811B or 511B horns and a set of 800 series HF drivers to go with either the 416 8A or B woofer.
XOs are many in this combo but most would go for an 800 series XO as well such as the 801, 809, 8500, or many of the others in this range. These components also can be nice with 1200Hz XOs for home environments.

Gary

[gamalot]

Forgot to mention that the A8 cabinets used a 515E woofer and I don't remember if they ever came with 416s. A8 style cabinets required mounting from the rear no matter which woofer you use.

Gary

[gamalot]

And another thought, Not to down play the virtues of the A8 design in any way but thats quite a large format speaker for most homes.

You might look around a bit and lean a little more toward the 846 style cabinets or the 19 cabinets for home use with most of the same components but a bit more home friendly cabinets.

A8s would certainly do the trick but your wife might not if you add them to the living room.

Gary

[LICORNE]

Hi Gamelot,

You quoted : [quote] Forgot to mention that the A8 cabinets used a 515E woofer and I don't remember if they ever came with 416s.


The A-8 came with the 416-8A . Assembled at the factory.The following web page lists the components with the A-8 as of 1978.

http://www.lansingheritage.org/image...pro/page04.jpg

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[LICORNE]

Hi Gamelot,

You quoted :

Forgot to mention that the A8 cabinets used a 515E woofer and I don't remember if they ever came with 416s.

<font size="2" face="Verdana, Helvetica, sans-serif">The A-8 came with the 416-8A . Assembled at the factory.The following web page lists the components with the A-8 as of 1978.

Forgot to mention that the A8 cabinets used a 515E woofer and I don't remember if they ever came with 416s.

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