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Replacing Large Advent Woofer Cones -- need advice


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#1 Guest_redtail_*

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Posted 01 August 2008 - 06:04 PM

I bought my New Large Wood Advent speakers in 1979. About 10 years ago, I had the foam surrounds on the woofers replaced. The surrounds have rotted out again, but this time the cones need to be replaced as well.

I searched but couldn't find anything about replacing the cones. I read the instructions on refoaming, and it doesn't sound that bad. So, is replacing the cones something I would be able to do myself? If so, can you recommend any place to get the new cones and surrounds? If not, should I take the woofers to a certified speaker repair shop, or what?

Thanks,
Doug

#2 Guest_SpruceMoose_*

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Posted 02 August 2008 - 02:32 PM

why do you need to replace the cones? physical damage? they do not generally go bad without a lot of "help". and it might not be worh repairing them, if you can find a good pair on the 'bay. i have bought 2 pairs of large and 2 pairs of smaller woofers over the past few years on the 'bay. some needed new foam, some were just fine as-is.

#3 Guest_redtail_*

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Posted 03 August 2008 - 02:06 AM

why do you need to replace the cones? physical damage?

Writing this makes me feel incredibly stupid, but...

When the surrounds went bad, they first simply separated from the cones. Not realizing that the foam had deteriorated, since there were no other signs -- and because I was dropped on my head as a small child -- I used some wholly inappropriate adhesive to re-glue the surrounds to the cones, and I did a quick, sloppy job. So, there is now a thin line of hardened goo around the edges of the cones. I don't think I can get the goo off without destroying the cones, and I can't image that it won't harm the speakers' sound.

I hate the idea of trashing the woofers because of my stupidity, but getting a pair from ebay may be the way to go. The tweeters were also shot, from old age and not abuse, and I replaced them with a pair from ebay -- an idea I got from this forum.

So, has anyone re-coned woofers, or should I just get a pair from ebay?

#4 Guest_SpruceMoose_*

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Posted 03 August 2008 - 02:29 AM

try using a single-edge razor blade to scrape the old glue from the edge of the cone. a very sharp, new blade should do the trick. thats what i use to remove the old foam from the cone.

#5 Pete B

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Posted 03 August 2008 - 03:48 AM

Writing this makes me feel incredibly stupid, but...

When the surrounds went bad, they first simply separated from the cones. Not realizing that the foam had deteriorated, since there were no other signs -- and because I was dropped on my head as a small child -- I used some wholly inappropriate adhesive to re-glue the surrounds to the cones, and I did a quick, sloppy job. So, there is now a thin line of hardened goo around the edges of the cones. I don't think I can get the goo off without destroying the cones, and I can't image that it won't harm the speakers' sound.

I hate the idea of trashing the woofers because of my stupidity, but getting a pair from ebay may be the way to go. The tweeters were also shot, from old age and not abuse, and I replaced them with a pair from ebay -- an idea I got from this forum.

So, has anyone re-coned woofers, or should I just get a pair from ebay?


I would not attempt to recone those woofers, you can't get the original
cone as far as I know, and aligning it will not be easy.

Depending on how thick and heavy the goo is it may not matter much.

I would just try to remove most of it where you will attach the new foam
and try gentle methods to remove the rest of the goo. I find that a Dremel
tool with the very fine and small wire brush works well if used very gently
on the cone. Also works well on the metal frame.

#6 Doug G.

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Posted 03 August 2008 - 01:59 PM

Get some Zip-Strip finish remover and spread it on the goop. I bet it softens it and you can easily wipe it off. :)

I agree that you shouldn't prolly replace the cones in that, if you don't use originals, they won't sound the same. eBay is a good woofer getting place. :lol:

Doug

#7 Guest_redtail_*

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Posted 03 August 2008 - 10:03 PM

I've been trying to remember exactly what the stereo repair shop did to my speakers 10 years ago. The more I think of it, the more I believe that the shop replaced the cones as well as the foam surrounds -- a nice way to make extra money, at my expense. So, would that argue for replacing rather than repairing them?

Also, I found these on ebay. I sent the seller a message asking a couple of questions, but he hasn't responded yet. What do you think?

Thanks for the help!

Doug

#8 Guest_SpruceMoose_*

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Posted 03 August 2008 - 10:16 PM

overpriced on the woofers and the shipping. pass.

#9 Doug G.

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Posted 06 August 2008 - 04:55 AM

I don't know. I don't think you did too bad. 45 bucks for two ready-to-go Advent woofers seems OK to me. ^_^

The only thing I don't like about them is the apparent large paper dust caps but I don't think we've ever definitively found that it makes a lot of difference in sound. Pete, have you ever tested this?

Do the cones in your originals look like the ones in the woofers from eBay with the six ridges? If not, then the shop DID replace them. A lot of "professionals" are anything but. ;)

Doug

#10 Pete B

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Posted 06 August 2008 - 02:04 PM

I don't know. I don't think you did too bad. 45 bucks for two ready-to-go Advent woofers seems OK to me. ^_^

The only thing I don't like about them is the apparent large paper dust caps but I don't think we've ever definitively found that it makes a lot of difference in sound. Pete, have you ever tested this?

Do the cones in your originals look like the ones in the woofers from eBay with the six ridges? If not, then the shop DID replace them. A lot of "professionals" are anything but. ;)

Doug


This is like asking if 2" dome drivers with different dome materials all sound
the same. The answer is no of course. I've not measured it on an Advent
woofer, but did many years ago.

Those look like they might be round magnet Jensen woofers or the current
replacements.

#11 Guest_redtail_*

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Posted 07 August 2008 - 07:58 PM

Those look like they might be round magnet Jensen woofers or the current
replacements.

Yep, my woofers were definitely reconed. I wish I had known then what I know now about replacing surrounds. Oh well.

I did receive a reply from the seller, and he said that they are the square magnet woofers, just like mine, from a pair of new large advents. He said they were refoamed and the frames refinished by a friend of his who "is in the business." I placed a bid on them, and won. When they arrive, I'll let you know how they are.

What's the controversy about the dustcaps?

My Advents have been out of action for about two years now, and I am really eager to have them working again.

Thanks for your advice and suggestions!

Doug H.

#12 Doug G.

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Posted 08 August 2008 - 02:24 AM

From one dog...er...Doug to another... ;)

The material from which the dust cap is made can affect the wave propagation of mainly the upper end of the driver's range. Advent originally used a cloth mesh cap which basically is pretty much transparent to the sound. You will notice that you can see through them. Also, this would provide a slow leak for the air trapped inside the cabinet. How necessary this is, I don't know.

A paper cap will actually propagate waves on its own and can affect the sound of the midrange frequencies of the speaker as a whole. How much, I don't know.

So there you have it, two paragraphs ending with "I don't know." Although there is definitely some effect with the different cap materials, the overall effect is, perhaps, not that great.

If you want your Advents to be closer to original, you can always remove the paper caps and replace them with similar diameter cloth caps. I did this on one of my pairs that had paper caps when I bought them.

Also, I'm sure Pete can give a more definitive description of the differences between the caps because, as one can discover by reading his posts, he has had much experience with the subject at hand.

Doug

#13 Carlspeak

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Posted 08 August 2008 - 11:05 AM

Porous dust caps were put on drivers for the purpose of voice coil cooling on vintage drivers. Another method used for cooling was perfing the voice coil former with a series of small holes just above the windings (below the spider). This was common practice in early AR woofers. A third method used most often nowadays is vented pole pieces; a simple hole right thru the back of the magnet. In the cases of perfed VC's and vented pole pieces you will commonly see non porous dust caps because the venting is taken care of in other ways.

IMHO, when refoaming requires DC removal, always replace the ORIGINAL DC with a DC of like construction. If you're replacing a screen DC with a plastic one, you're asking for trouble if you like your music a 90+dB all the time

There are 4 types of DC's commonly available today. Screen, felt, paper and plastic. Screen is most porous with felt next with some permeability and paper and plastic last; both providing no breathability.
IT'S ALL ABOUT THE MUSIC!

Carl
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#14 Guest_redtail_*

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Posted 11 August 2008 - 03:04 PM

Thanks for the information about the dust caps. I think my original cones had cloth dustcaps, but I'm not sure. The cones were replaced so long ago that I really can't remember what they looked like. Regardless of the effect of the paper dust caps, I'm betting that the replacement woofers I won will sound better than my re-coned original woofers.

Doug H.

#15 Doug G.

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Posted 12 August 2008 - 01:08 AM

Your original woofers would have had the porous dust caps which is the same as saying cloth pretty much. Actually a very thin black, stiff gauze type material. You can see the pole piece through it.

When you get the eBay woofers, you will see what the original cones are like as these are originals. They have six ridges around the outer diameter and are a relatively thick pulpy type of paper. The rear surface is very irregular.

These were made using a low pressure vacuum to mold them out of a kind of paper slurry.

I bet they will sound better than the reconed ones too.

Doug

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Posted 14 August 2008 - 04:45 PM

The woofers arrived yesterday. I put them in as soon as I got home from work. They are in great shape, and they work perfectly, as do the replacement tweeters I bought a couple of weeks ago. I had been using a cheap set of speakers since my Advents died, and it is wonderful to have good speakers again.

How did I spend the rest of the night? Yup, listening to some of my favorite music on my reborn Advents: Steely Dan's Aja, Joni Mitchell's Hejira, the Roche's first album, Copeland's "Quiet City," and some Debussy piano music. Although I hadn't forgotten how good music sounds when played through Advents, it was almost like listening to a good system for the first time. Oh my...I got to bed late. Thank God for caffeine.

By the way, the dust caps are definitely woven. I can see the weave, and light from a flashlight shines through.

Thanks again, everyone for your help and advice.

#17 Doug G.

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Posted 15 August 2008 - 12:48 AM

Great news on the dust caps. Even though they are a larger diameter than the originals, if they are porous, I don't think it makes much difference.

Also, I see the surrounds appear to be the correct large-roll type. I see way too many on eBay that have a way tiny roll.

It has been only recently through discussions here and other speaker forums that speaker owners are becoming more aware of the importance of having correctly configured and correct thickness surrounds installed as opposed to ones that merely "fit" right.

Doug




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