Altec A-7 500 Damping

[Jimmy-time]

During my restoration of the Altec A-7 500 "Voice of the Theater" I've noticed that the original damping material appears to be regular yellow colored home insulation? Question 1) Leave it intact or 2) Replace with some improved damping material in same location as original or 3) Someone has already designed the best damping technique for these speakers and it is listed somewhere online?

Question #2 After sanding down the cabinet I've noticed spaces at the base of the section where the flared plywood on the inner 2 sides meets the plywwod on the floor of this area in both speakers. (base of port built around woofer) Should this be filled in with caulking or is this space intentional for some acoustic property?

If anyone has any ideas I appreciate it. Jimmy-time

[Altec Best]

If it is in good condition I would reuse it... If not use the same thing that is there...

[Alien_Shore]

It certainly won't hurt to replace the insulation to get rid of the years of dust and whatever else might have taken up in there.
Since you're refurbing, you really should read Altec's speaker enclosure pamphlets. There are several online, and each has it's own interesting information in there.

As far as the gap goes on the horn flare, I think that should be sealed up. Can you post a picture?

[cradeldorf]

Yep, horn flare shouldn't have any gaps in it.

[Jimmy-time]

Yep, horn flare shouldn't have any gaps in it.

Great will correct tonight, thanks for the insight. Jimmy-time

[Cal Weldon]

Consider replacing the yellow fiberglass insulation with rockwool (good for sound) or polyester (pillow stuffing. Requires twice as much but safer)

[Jimmy-time]

It certainly won't hurt to replace the insulation to get rid of the years of dust and whatever else might have taken up in there.
Since you're refurbing, you really should read Altec's speaker enclosure pamphlets. There are several online, and each has it's own interesting information in there.As far as the gap goes on the horn flare, I think that should be sealed up. Can you post a picture?

Awesome, I will review the pamphlets. I am glad I can remove the old insulation, they are really dirty and ripped in places. Does anyone ever skip the yellow home insulation and buy high end modern damping material? The horn flare will get sealed tonight. I have a picture posted in my "Altec Voice of the Theater Part 2" blog which can be viewed. Thanks. Jimmy-time

[Altec Best]

Most folks want to keep them looking as original as possible with them sounding as best as they can... Do some unseen or easy to change Mods to keep as close to original just in case you ever want to sell them... Custom cabs won't sell as fast and won't bring as much money as all original Altec IMHO !!

[Panomaniac]

Fiberglass works well, still to this day - pink white or yellow. If you want something more friendly and that works great, look for Bonded Logic insulation. It's made from recycled denim. A very good acoustic damping material. Doesn't itch.

You'll want to do some cross bracing and damping of the bass horn flares if it have not yet been done.