DIY asilker's Altec VOTT thread

Do It Yourself
Horns have been wiped with citristrip. This stuff smells like urinal cakes. All of a sudden im in a suburban park bathroom in the summertime

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I am going to bust the cabinets back down today. There are a few places that require touchups, but before I bounce over to rollers, let's try "distressed" one more time.
 
My two cents.

Painting the horn a bold color draws all attention to the horn - it loses visual balance.

Don't do it.

(slowly backing out of the room :)
 
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Busted back down. This is how they'll stay. My partner says they'll look good in the living room if we lean into the patina. I think she's right.
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The horns will remain raw (uncoated) aluminum. Here's a photo of 6061 that's been brushed and left to oxidize. The horns will get the same treatment.
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Found this really interesting in @Ampexed guidance on the Hoffman forum.

The high frequency 811 and 511 horns have a problem with resonance. Under some circumstance they will ring like a bell, which is obviously not great. Mounting these horns onto a baffle helps somewhat but this does not alleviate the problem completely. The solution is to apply a thickness of about 1/2" of damping material to the entire exterior of these horns. The factory used Aquaplas for their sectoral horns and on later 511 horns, though not of sufficient thickness in my opinion. By the way, Aquaplas is the substance which was sprayed on the older JBL woofers and this made them their signature white color. I use Aquaplas on my horns but unfortunately it seems to no longer be available. Fortunately there is a readily available alternative - Bondo automotive putty which is sold in any auto parts store. Apply about 1/2" of Bondo to the entire exterior of the horn, even the front portion of the horn in front of the mounting flange. Be careful to work quickly because Bondo has a fast set-up time. You might want to work up thinner layers so that the Bondo doesn't start to set up before you're done spreading it out. When done, spray painting the exterior with Krylon Satin Black improves the appearance. After applying the Bondo, rapping the horn with your knuckles will reveal an absolute lack of any resonances.

The low frequency horn has several problem areas. These are the sides, the upper and lower rear, the boards which form the bass reflex port, the top of the cabinet, and the sides and bottom of the bass horn. The sides of the cabinet can be stiffened by applying edge-wise 2x4s diagonally on each side. Likewise the lower back. Apply new fiberglass batting over these boards. I have applied a 3/4" thickness of Baltic Birch plywood to the back of the port boards. For the removable upper back, I constructed a new one by laminating two thicknesses of 3/4" Baltic Birch together.

The sides of the low frequency horn are so thin that they seem more like the body of a guitar. While not absolutely mandatory, you might wish to deal with this. Apply a 1/2" thickness of Bondo to the inside walls of this horn. I followed up by applying a couple inch thickness of a mixture of sand and plaster on top of the Bondo, then fiberglass on top of this. The sand/plaster is more optional however. The lower side of the horn can be stiffened by placing a 2x4 on edge across the middle, inside the cabinet, and fiberglass over this. For the top of the cabinet, anything you do here will degrade the cabinet visually, so what I do is place a couple of 5 or 10 pound sand bags on top. These can be purchased from photo supply shops.
 
I used 25 pound bags of lead shot on some horns I suspected of "ringing". Cheaper than camera stuff. Listen ad decide for yourself before altering the Altecs. IMHO
 
The deadening spray I refer to earlier in the thread actually does a great job. Untreated 511 and 811 horns you can hear ring by just thumping it with your knuckle. After the spray no ring with a thump.
 
I am in the enviable position of receiving multitudinous points of guidance. So far I've appreciated all of it -- I'll need to choose a way forward so I hope it doesn't feel adversarial if I choose one approach over another

For the time being I plan on running the horns as is / undamped until I feel I have a sense of how they naturally behave. Art Dudley and Jean Hiraga have both advocated for allowing Altec systems to resonate. I'd like to challenge myself to make these sound good without significantly altering their character.

I will say that I find the 3m spray compelling. I prefer not to work with Bondo. Fill and mud type products are challenging for me and I'm never quite happy with the results.

Here's after one application of Citristrip. @Redboy , great recommendation.
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If you want a real nice alloy finish, vapor/bead blasting with glass beads. The glass gives a semi matte finish that is more resistant to uneven oxidation.

It will also give a nice clean even finish well into the throat and joins that will prove useful if you want to spray as it will be smooth as.

35 yo Norton parts blasted and before polishing.

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For the time being I plan on running the horns as is / undamped until I feel I have a sense of how they naturally behave. Art Dudley and Jean Hiraga have both advocated for allowing Altec systems to resonate. I'd like to challenge myself to make these sound good without significantly altering their character.

IIRC, Joe Roberts was trying to arrange sending a pair of Altec 32 horns to Art. Sadly it never materialized due to Art's untimely demise.

FWIW, I haven't encountered an article wherein Jean Hiraga was using the small format Altec A-7 (811/511 + 802). He's associated with the large format A-5 (e.g. 1505 + 288) wherein his crossover design for that system was published in Sound Practices. If I'm mistaken, please send me a link, I'd be interested to know his opinion re: 811/511.
 
IIRC, Joe Roberts was trying to arrange sending a pair of Altec 32 horns to Art. Sadly it never materialized due to Art's untimely demise.

FWIW, I haven't encountered an article wherein Jean Hiraga was using the small format Altec A-7 (811/511 + 802). He's associated with the large format A-5 (e.g. 1505 + 288) wherein his crossover design for that system was published in Sound Practices. If I'm mistaken, please send me a link, I'd be interested to know his opinion re: 811/511.
I believe you're correct. I'm not aware of Mr, Hiraga making any comments about the 511/811 either, but I seem to remember him remarking on cabinet resonances. I don't have a link on hand so I may be wrong.

Art discusses 811 resonances in Listening #125 HERE (je, I'm sure you're already aware)

Do you have any philosophy on horn and/or cabinet resonance?
 
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I have read many comments on allowing the cabinets to resonate vs bracing.
Some say they sound better with out.
I almost got a 2nd pair of cabs to try ( didn't want to cut mine out )
And then got side tracked with my TA-7331-A project.
 
My experience with horn +cabinet resonance was with Klipsch Heresy(2 identical pairs). One pair I did not touch, the other I dampened the horns and braced the cabinets. The difference was obvious! The best I can describe the sound is cleaner and more detailed.
 
IIRC, Joe Roberts was trying to arrange sending a pair of Altec 32 horns to Art. Sadly it never materialized due to Art's untimely demise.
I had to smile when I read this. Way back at the 2011 RMAF, where Joe Roberts was demonstrating a WE 757a system in the Silbatone room, I talked to Joe about Altec speakers. When I told him I used Altec 32 horns, he said they were “junk” and “garbage.” Joe is no Casper Milk Toast when it comes to expressing his opinion! We agreed to disagree. A couple years later, Joe said on another forum that he was using Altec 32 horns with 802 drivers and really liked the sound. I posted something reminding him of his comments at RMAF and Joe to his credit apologized for his earlier dismissal of the 32 and 802. I guess that just goes to show opinions can change.

In my case, I first started listening to the Altec 32B and 802-G back around 2007. I loved the sound back then as it was the first horn I had heard that didn’t have a shrill, shrieking sound, and I have loved the 32 ever since. Over time I switched to WE 32A horns. I really can’t imagine ever changing to something else.
 
Art discusses 811 resonances in Listening #125 HERE (je, I'm sure you're already aware)

That's why J-Rob wanted to send him a pair of Altec 32s.😊

Do you have any philosophy on horn and/or cabinet resonance?

My entire Altec experience, particularly my struggle with the sand cast 811 and its throat geometry, is documented in my blog. I continue to update it as I learn along the way. That's why I was curious to know if Jean Hiraga published anything about the 811 or 511.

I had to smile when I read this. Way back at the 2011 RMAF, where Joe Roberts was demonstrating a WE 757a system in the Silbatone room, I talked to Joe about Altec speakers. When I told him I used Altec 32 horns, he said they were “junk” and “garbage.” Joe is no Casper Milk Toast when it comes to expressing his opinion! We agreed to disagree. A couple years later, Joe said on another forum that he was using Altec 32 horns with 802 drivers and really liked the sound. I posted something reminding him of his comments at RMAF and Joe to his credit apologized for his earlier dismissal of the 32 and 802. I guess that just goes to show opinions can change.

In my case, I first started listening to the Altec 32B and 802-G back around 2007. I loved the sound back then as it was the first horn I had heard that didn’t have a shrill, shrieking sound, and I have loved the 32 ever since. Over time I switched to WE 32A horns. I really can’t imagine ever changing to something else.

Typical J-Rob.😆 Thanks for sharing this @Salectric!
 
I called GPA this week and sent an inquiry email for 416 recone parts, and I haven't heard back.

I see aftermarket kits through Simply Speakers and the Speaker Exchange. I realize there's a general preference for GPA over aftermarket, but I might be operating with limited availability here.

Does anyone have a comment about aftermarket recones, or other suggestions?

My intention in reconing as a 416 is motivated by:
- way more hobbyist info available for the 416. Not many folks are building around the 421a
- I may be able to push the low end extension down just a bit further
 
I called GPA this week and sent an inquiry email for 416 recone parts, and I haven't heard back.

I see aftermarket kits through Simply Speakers and the Speaker Exchange. I realize there's a general preference for GPA over aftermarket, but I might be operating with limited availability here.

Does anyone have a comment about aftermarket recones, or other suggestions?

My intention in reconing as a 416 is motivated by:
- way more hobbyist info available for the 416. Not many folks are building around the 421a
- I may be able to push the low end extension down just a bit further
Even in GPA's heyday they never answered e-mails. I would call them. Bill always answered the phone. Pretty sure Bill has retired, Hopefully someone learned from him.
 
Even in GPA's heyday they never answered e-mails. I would call them. Bill always answered the phone. Pretty sure Bill has retired, Hopefully someone learned from him.
I called and left a message this week too 👍

I'll try again this week
 
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