Altec Build

[jeffjmr]

Here's the bad one. Each rip is two to three inches long and nearly connected around the rim. Plus there is a small one inch on the opposite side. I'd say this one is toast.




This one looks repairable.



I've seen two methods. VolvoHeretic seems to have had luck with silicone caulk. Elsewhere I have seen suggestions of using tissue paper with thinned Elmer's Glue. The caulk idea sounds better to me.

Luckily, the other two 515 cones are free of damage, best I can tell.

Jeff

[jeffjmr]

If you are thinking of 2 x 15 cabs....the ones with newer cones should have more lows. Put them on the bottom. If you want an inductor in series will roll off the upper mid.

Put the originals with the light cones on top. This is where you want the most upper mid anyway. then horns on top of that.

JBL DID NOT invent the concept, but here is a link to an SR box that uses that principle.

JBL :: Product

This preserves the original two and lets you use the reconed pair. Also deals with the differing response.

I suggest separate top and bottom chambers tuned to each.

So Old Guy, if I did that, do I need an additional crossover for the mismatched 515, or can the reconed and original coned remain in parallel? And tuned chambers means I must abandon my plan for 817 cabs, no?

[Altec Best]

I'd say this one is toast.

Not necessarily ! If you can glue the cracks with a light weight glue/adhesive or something you maybe able to repair them.You have nothing to loose by trying.Or try Volvoheretics suggestion.But I would try to repair the cones first. I've seen a lot worse repaired than those rips you have so give it a whirl.

Or you can try this paper cement that should work well. You can thin it to a thinner consistency as well which I would recommend it should be easier to apply a couple thin coats then one thick coat.Besides you don't want to add much weight to the cone anyway.

http://papercement.com

http://papercement.com/usage.html

or here's a couple more options.

http://www.ehow.com/how_2120754_repair-speaker-cones.html

http://www.ehow.com/how_4828671_fix-torn-speaker-cone.html

I also came across this thread on repairing cones at AK

http://audiokarma.org/forums/showthread.php?t=142612

And this on Youtube.

http://youtu.be/hSbTbuZ-55Q

[VolvoHeretic]

They can both be fixed. Cut the tape into short stips to follow the rips, just like masking off a car for painting and caulk away. Silicone only sticks to two things, glass and paper, and to those extremely well.

Edit; the problem I see with rubber cement is that over time, it dries out and disintegrates, silicone should last forever.

Second edit; if those had the tar/cloth surround I would recommend oil based Geocel caulk which even sticks to asphalt shingles, and even when wet.

[jeffjmr]

OK, I am now deeply indebted to you all. Repairing the rips has been easier and more successful than I had imagined.

The worst as seen in the top photo, however, is ripped also along the perimeter along the hold down ring. My question is, does anyone know if the cone is under tension? In other words, can I safely remove the ring around the surround in order to repair the perimeter rips without the cone pulling away from the ring?

By the way I'm using an acid-free adhesive I use to repair books that remains flexible and seems to be doing the job. Where the rips are larger I am reinforcing with tissue paper though I think I would be better off with something more robust.

Cheers,
Jeff

[Altec Best]

Double up the tissue paper to make it thicker you may have to apply a few times,just apply glue between the sheets of paper then apply the thicker paper. Good Luck with it !

[westend9]

Although the one cone is in bad shape, both of those will play nicely after repair. Your choice of conservation adhesive sounds like a good idea. As was posted, you can double layer the tissue paper or use thicker stock but it probably won't be necesary to add a lot of strength to the damaged area. If the adhesive is good, it does most of the holding. I've repaired much greater cone damage and had good success.

Good luck on your speaker build!

[GM]

In other words, can I safely remove the ring around the surround in order to repair the perimeter rips without the cone pulling away from the ring?

By the way I'm using an acid-free adhesive I use to repair books that remains flexible..........

Yes, the spider centers it, holds it all together.

I assume you mean this PVA or similar adhesive for general repairs: Lineco Neutral pH Adhesive - BLICK art materials

FWIW, I've used various household tissues to successfully repair inexpensive car audio or similar 'robust' drivers, but prefer to use proper archival tissue, hinging tape and appropriate adhesive for high Vas, wide BW drivers such as Altec or similar: Lineco - BLICK art materials

GM

[Panomaniac]

Thanks for the tips, GM!

[jeffjmr]

Yes, the spider centers it, holds it all together.

I assume you mean this PVA or similar adhesive for general repairs: Lineco Neutral pH Adhesive - BLICK art materials

FWIW, I've used various household tissues to successfully repair inexpensive car audio or similar 'robust' drivers, but prefer to use proper archival tissue, hinging tape and appropriate adhesive for high Vas, wide BW drivers such as Altec or similar: Lineco - BLICK art materials

GM

Not Lineco but similar product from BrodArt. And I think I have come up with a great tissue; Kodak lens cleaning paper is at least as thin and light as packing tissue, but maintains its strength when wet making it much easier to work with and position with the wet glue. Where there were gaps that I could not close, I covered with the tissue, but backed it up with a very small dab of the silicone VolvoHeretic recommended.

I'll send pictures tonight as I believe I am finished. The worse cone is not pretty; it was split along the periphery of the ring, and depressed inward across the surround. I could not apply the repair from behind and I found it impossible to reshape the surround part of the cone as its wavy shape blends into the straight part of the cone, but I think the repair will hold.

If I could have removed the cone entirely and work from the backside without the interference from the frame it would have come out better. I did remove the ring and nothing moved, as you said the spider holds it all in place.

I'm going to do a free air sound test to compare it to the other 515s that are flawless to see if there are any obvious anomolies.

Thanks all for your valuable input.

Jeff