Altec Build

[Panomaniac]

I am the fortunate owner of 4 each 288B's and 515's, and two N500C's.

This is a really bad spot to be in, I feel bad for you.

Since you have 4 515s, do you have room for an Onken W cabinet? It is quite amazing. Big and heavy, tho. Internal dimensions are 107cm x 77cm x 55cm or 42"W x 30.3H" x 21.6"D As big as an A7 on its side, plus all the thick walls. But the cleanest, best bass I've ever heard.
On top of that I'd put a multi-cell like a 1005 or 1505. Sell one pair of your 288s and you could pay for that. Alternately there is a guy in Poland making great horns at great prices. All sorts of shapes and sizes. A buddy of mine in Hawaii bought mid and high horns from him at my recommendation and is super happy with them.

[jeffjmr]

Pano, I actually started accumulating and studying the plans for A7s (210 cabs) when I first acquired the drivers since they came out of an A7 and the cabs were ruined. I was sure this was the only way to assure that clean, live-like bass is felt as well as heard.

My wife saw me perusing them one night, and when she saw the dimensions, politely inquired as to whose house, besides ours, I was planning to install them in!!??

The friend who gave these to me made me promise to use them or return them to him. He died of cancer two years ago and I am determined to keep my promise.

So 817s or cabs of similar dimensions is all I'm going to get away with. AB's suggestion of modifying 511s sounds appealing, but I would like to explore the Poland connection as well. There is an Emilar model EH-500 that looks interesting, too, though prices on them have gone from ridiculously cheap to rather expensive over a very short period of time.

Where can I learn more about the horns you mention?

[Altec Best]

AB, the woofers are straight 515s, but will go to GPA for remag and any other useful mods that won't break the bank.

Jeff I don't think GPA has the same cones you have on those.The 515 came with a paper surround.They would probably be reconed with the cloth/pleated surrounds.Not necessarily a bad thing but if the cones are fine I would leave them.

[Audio_by_Goodwill]

Pano, I actually started accumulating and studying the plans for A7s (210 cabs).......

A7's don't' use 210 cabinets. The A2, and A4 systems do.

[Panomaniac]

Correct-o! A7 used the 825/828 bass cabinet and a 511 or 811 (mostly).
I'll dig up the info on the Polish horns.

EDIT: Here is the website. Tons of choices. They come in colors, too - I think.
http://www.horns.pl/index.html

[jeffjmr]

A7's don't' use 210 cabinets. The A2, and A4 systems do.

You're right. They were A4s. I have A7s on the brain.

[jeffjmr]

Jeff I don't think GPA has the same cones you have on those.The 515 came with a paper surround.They would probably be reconed with the cloth/pleated surrounds.Not necessarily a bad thing but if the cones are fine I would leave them.

Two are OK, two are ripped. Sort of makes me wonder how to pair them if I only recone two of them.

Any thoughts on my question about cutting down the 511s?

[GM]

Greets!

515s have somewhat different specs than the later B, C, etc, instead being closer to the 515-8Gs [higher Fs, lower Vas], so not a good match-up if re-coned unless GPA has a parts combination to get close enough specs and HF BW ?tone? as there's no more originals available.

There's also the question as to whether GPA can still re-cone/re-zap to 'powerful' motor [low Qts] specs since lately there's been some folks getting relatively 'weak' motored [medium high Qts] re-cones. This isn't necessarily a bad thing if one plans to use a large cab or OB and drive it with a typical SS amp, but tubes, especially SET, need a powerful motor to keep from being under-damped in operation.

Yes, the 511 can be cut down to where the throat area is the same as the driver?s exit = ~1.54?^2 and add a mounting flange same as the factory did. Easiest/most accurate I guess would be to get AB to make an accurate length measurement from the front of one of his factory conversions.

Anyway, all things considered, unless you just have a keen desire to keep the 288Bs and good 515s, then consider selling them since they historically bring big $$$, even blown ones in some cases to fund new, or at least later, versions depending on the needs of your app. Depending on the parts condition and market, you might even wind up with enough extra to completely fund the project.

WRT horns, consider using two 511B/1? driver/speaker as I once did to replace 805/288B to ?have my cake and eat it too? since I wanted the fuller mids of the 805 and the extended HF of the then current 802. This combo actually makes for a bit larger effective horn and driver, though never having compared the two side by side, can?t say if it?s audibly noticeable, at least with a 500 Hz XO.

GM

[Altec Best]

Easiest/most accurate I guess would be to get AB to make an accurate length measurement from the front of one of his factory conversions.

If you decide to do the cutdown of the 511B's "Not A Problem" I would be happy to get all the relevent measurements for you !

[GM]

........210 cabs..........I was sure this was the only way to assure that clean, live-like bass is felt as well as heard.

So 817s or cabs of similar dimensions is all I'm going to get away with.

FWIW, I had 210s for decades, though I cut the reflex box off, braced them real good and added a triangular shaped compression chamber, so they would fit sideways in the corners like 211s minus reflex vents. This way they only intruded a relatively minor amount [bisecting the corner ~ 4 ft out]. A pair of dual 515B ?subs? that did double duty as the horn?s ?stands? covered the lows.

As much as I enjoyed them, I never could completely cure its response issues with parallel horn walls and the slightly ?pinched? mids due to throat distortion, so when I was forced to sell them I was pleasantly surprised to find I much preferred the more open sound of just the ?subs?; and at ~104 dB efficient in-room, don?t miss the ~8 dB/channel loss even at high SPL, so would never consider mid-bass horns again over dual 15? or larger drivers except maybe conical to control directivity if I should ever again have a really large room that needed it and/or was forced to downsize the driver[s].

If you DIY 817s, then I strongly recommend modding them to have no parallel walls, i.e. make it a dual driver 825/828 horn. Since they are shorter/smaller, throat distortion is negligible except at higher XO points, at least I didn?t notice enough to be distracting back in my youth with DIY A7-500s compared to the A7-8, and especially the later 1200 Hz MI versions.

GM