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Summer Altec A7 project (Done)


kg4guy

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Picked up another pair of Altec A7 cabinets yesterday they have classic grey paint in nice condition I'm planning to repaint them the same color I ordered 4 new decals for the sides I have 909-16 drivers a pair of 511B horns has anyone considered powder coating the 511B's ? I have a pair of Eminence Kappa C woofers I'm going to try with them and if they don't sound good I guess I'll order new 416's from GPA. Going to use a Ashly XR1001 active with them with a BGW 750C on the LF and a BGW 250D on the HF and we shall see what happens.[:o]

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I heard a set of A7's with original drivers and they sounded great for top end and down to upper mid bass. Knowing how you like to tinker.....I would expect that eventually your going to stack these on top of your MWM's .

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Finished painting both of them moved one in the garage the test using Kappa C woofers and the 909-16's with the 542 horns as my 511's are getting painted black running them with two BGW amps 750C on the LF and a 250D on the HF with a Ashly XR1001 active .

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  • 2 weeks later...

Well got one fully done today I think I will stick with the Eminence Kappa C's the specs are very similar to the GPA 515 8G Qts and Qes are the same as is the Vas is 11.7 on the Kappa C and 12.4 on the 515 8G the Qms is 10 on the Kappa C and 5 on the GPA 515 8G not sure how much of a difference this will make the x max is 2.5mm vs 5mm on the GPA 515 G8 but the Kappa C is 4 ohm vs 8 ohm. I have a pair of JBL 2404 tweeters I may use them for kicks as I built a passive 4th order Linkwitz filter for them so I can still use the Ashly XR1001.

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These are BEAUTIFUL. Ok now I'm gonna get to work on mine. So basically you have Altec box and horn and all the innards are something else readily available. I like it. I know where there's a XR1001 cheap around here and amps are everywhere around the shop. Thanks for taking time to photograph the process. M

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On the A7 (825) the one board is 8", the other is 4-3/4", and the port opening is thus 7-3/4" (1968 plans).

The cloth is just stapled in place and painted.

"Seems like there should be some brace behind those panels too."

I agree, but the whole box is very lacking in bracing.

If you want to build something that really kicks butt big time, build a pair of my dual 15 PPSL , use a V.O.T.T. sized mid-bass horn with a 12, and put the HF horn on top. With the Kappa Pro 15LF II it will be 104dB/2.83V/1M, and be flat to 35hz. The stack will only be about 2" taller than the A7, and lay waste to a pair of Klipschorns.

Visualize this stack with only one mid and one bass cabinet.

http://i56.photobucket.com/albums/g196/dkleitsch/CoePA-2009.jpg

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These are BEAUTIFUL. Ok now I'm gonna get to work on mine. So basically you have Altec box and horn and all the innards are something else readily available. I like it. I know where there's a XR1001 cheap around here and amps are everywhere around the shop. Thanks for taking time to photograph the process. M

The mid is a Altec 909-16 apart from the 511B and the cabinets yes the woofer and the networks aren't. I got my Ashly XR1001 at Guitar Center for around $150. in excellent condition also got a brand new Altec 511B horn in original box with mounting gear from the Guitar Center for $19. plus $10 shipping $%#$%&&&? ??
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DJK: what are the approximate crossover points on your system shown in the link? What amount of compression is on the midrange (2:1 ?) and does a midrange horn that short provide much horn loading below 200 - 300Hz or so.

I have an Altec A7 cabinet in my garage. I have never bothered with making an impedance measure, but I have always assumed the bass really did not have much loading with that short horn path. (using a 1/4 wavelength as a rule of thumb)

A note to others. If the size of the vent is reduced to about 60-75 sq in, the bass will sound better. Bracing can also be retrofit behind the flared walls

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