is it possible to use a 12 inch in 816 cab?

[MERDY]

i have these cabs lying in my attic for years and slowly selling and getting rid of stuff, i was wondering if i can use the 12 inch altecs in the cab
my idea was to keep the horn flare vertical with a 3cft sub below and a 3 cft cab for the driver with the flare , think split micro a4, this vertical tower will be used for my bedroom ht setup
am i real?

[GM]

Greets!

The horn part will work fine, but the rear chamber Vb/tuning will be too large/too low, though it can be dialed in using some series resistance to flatten it, with the attendant loss of efficiency of course.

GM

[MERDY]

ok understand that ,what if i make a new box for the 12 and only use the horn flare is there a way to figure out the baffle cutout or the throat, i am now envisioning that it will look like a radar in the cartoons
altec never did make a 12 inch driver flare did they? did see some peavy horns in the seventies which is why i was wondering
appericate your help

[GM]

Greets!

You're welcome!

Not that I recall.

Huh?! Do you mean put the driver in a sealed cab inside the 816? This will raise Fc too high unless your sub has a higher usable BW than typical.

The driver needs to mount against the baffle board, so air tight inserts are required.

GM

[MERDY]

Gm your a gem,
after inspecting the cabs this is where i want to go ,will cutoff the bottom port part and but a new baffle board completly from end to end, thus 3.5 cft, on the cutout for the baffle how does one redo the correct cutout for a 12 as i would think that the new throat would have to be correct to get all paremeters in order
or i could completly cut out the flare part and attach it to new box baffle , looking for 100 hz to 800
cheers

[GM]

Greets!

A horn's throat isn't the driver's cutout unless the two are one and the same, so in this case, the throat area (St) is 8"x16" = 128"^2, which means it's HF BW is done by ~338 Hz, so above this point the driver is in direct radiator mode and the horn is strictly a waveguide (WG). How big the driver is only determines its total acoustic power since obviously a 15" driver has a lot more acoustic efficiency than say a wide BW 4" which could be used too. As a side note, a typical 15" prosound driver's Sd = ~128"^2, so while the driver looks like it's mildly compression loaded, acoustically it's not, ergo it's a 1:1 compression ratio (CR).

The mouth area (Sm) dictates the horn's Fc, or ~179 Hz, and with a 1/2 WL of ~484 Hz, it's the rear chamber alignment that determines how quickly it will roll off below Fc, so you have to play with vent sizes to find the flatest response to 100 Hz.

GM

[MERDY]

Got it will put on a dunce cap and stay in the corner during desperate housewifes
will play with speaker design software and see and in the end i might just stick to a 15
cheers

[misterdwayne]

FWIW, Bozak used to make a cast aluminum ring flange type thingy for their b207 speakers, that would mount to a 15" cutout and hold a 12" b199 woofer speaker in the center. They show up on Ebay occasionally. I actually was in to Bozak, still am, but don't have the room for both Altec A7's and the Bozak towers.

PS. I have some 299 16a drivers on Ebay currently