Altec cabinet project..?

[aauwen]

Hi all,

I currently have a pair of 311-90s with 288-16H drivers sitting on top of Khorn bass bins.

Though the current set-up sounds good to my ears, it just seems like it would be more appropriate to at least give them a try with Altec cabinets.

Would these cabinets be good candidates for a restoraton project, or should I consider building a pair of new cabinets?

A-7 Cabinets

Other than woofers, I also have a couple of other horn/driver combinations that I want to try on the Khorns, as well as on the Altecs.

Thanks,

<font color="#FFFFFF" size="1">[ June 18, 2008 08:04 PM: Message edited by: aauwen ]</font>

[LICORNE]

I find the picture has some touch up paint.
For 50$ if they are rock solid go for it.
A good sanding a new paint and voil? . VOICE OF THE THEATER. Don't forget 2 416 or 515 G and matching XO.

...................................

[bowtie427ss]

Convergence is spot on.

You'll be hard pressed to buy 1 sheet of quality plywood for that same 50 bucks.

Original factory boxes are a great starting point almost regardless of condition. Many improvements can be made by adding internal bracing to the back of the horn flares and box proper, additionally, stuffing and sealing off the volume behind the horn flares to reduce overall reflex volume seems to help reinforce the bottom end response a bit.

[cclark65]

yea, someday I'd love to have a set of A7's. A guy I know has a couple out in his BARN!?!? that are dying with the freezing cold in the winter and heat/humidity in the summer, but he won't get rid of them :-( They have 416's in them, and 511b horns with blown diaphragms.

[GM]

FYI, these are 825 cabs with low pass filters (the driver cutout) optimized for 811/800 Hz, so in theory you'll need a higher than stock XO slope order to attenuate its extended HF beaming when using lower XO points unless very narrow directivity horns are used. Hardly a deal breaker though considering the cost of void free plywood these days........

GM

[aeyb701]

Hi GM:
What do you mean the 825 is ported or cut out for the 811/800 drivers, when the 825 is for a LF driver with the HF driver sitting on top usually, irrespective of port or woofer opening? Is this not the same 825 that was also used for the a7-500, with a different HF horn and Xover?
I'm confused, so forgive my ignorance.
Jon A.

[BoydB]

Joe, as a 'plan B' option to getting those 825 cabs, I've some spare empty 828's that I could loan, I'm 80 miles south of you in Peoria, AZ.

Boyd

[aeyb701]

PS... GM: Do you mean that the 311 horn would need a differently-sloped XO than the 811/511 horns in order not to overlap too much at the upper end of the LF cabinet's output?
Jon

[GM]

Originally posted by bowtie427ss:

An important detail that i think gets commonly overlooked by many folks.

............ many thanks!

<font size="2" face="Verdana, Helvetica, sans-serif">You're welcome! Not sure how important it is since I've never done any side by side hearing or measurement comparisons, but I wanted to point it out as a potential problem WRT blending larger horns, lower XO points. Indeed, Altec later dropped the A7-8 spec cab, using the larger A5 hi-pass filter for all versions, though I assume it was done without Engineering's blessing.

GM

[GM]

Originally posted by aeyb701:

Is this not the same 825 that was also used for the a7-500?

.........would need a differently-sloped XO than the 811/511 horns in order not to overlap too much at the upper end of the LF cabinet's output?
Jon

<font size="2" face="Verdana, Helvetica, sans-serif">Greets!

Not originally AFAIK.

The woofer baffle's cutout on these particular cabs has a smaller area than the A5's full horn baffle width cutout. This smaller area means there's more air trapped between the driver and baffle, ergo the horn's throat (the area defined by its 8'' x 16" baffle dims) is compression loaded to a higher frequency.

Right, the woofer will be beaming more in these A7-8 cabs than in the more common A5/A7-500 version, so in theory a steeper XO slope is required to roll off this extra gain BW when using a lower than 800 Hz XO point.

GM