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DavidDru

AR 11" woofer driver refoam (AR9)

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Maybe you guys can help me make sure I get this right. Shouldn't be difficult but there may be some things you might offer up as I go here.

As you may recall from my AR9 thread, while the 4 woofers all worked, they had been refoamed along the way. Rather oddly as can be seen in the photos. Almost like they put them on upside down just to get them to fit. Must have not had the correct surrounds.

I removed the old surrounds on 2 of the drivers last night. Came off fine, but I will scratch at the edges a little more maybe. I like to use a dull exacto blade to help as I go. Since these were replacements they weren't as deteriorated as we often see when removing old foams. Plus it's the 2nd coat of glue. Otherwise these cones are pretty tough and I really wasn't worried about them as I went. I dont think I want to use rubbing alcohol pr acetone on the cone edges unless you guys think I can. They are pretty smooth now.

You will also see the staining on the cone of the one as well as the associated surface corrosion on the frame that I will have to clean up. Would still like some ideas on how to clean the cones if possible. The woofers on the AR9's are of course down low on the sides of the cabinet and these no longer had the grilles so were exposed to lord knows what. Could even be cat urine although no smell.

Now I also am wondering about the cardboard ring that is attached to each frame. I assume those are not supposed to be there? Something the previous effort added to make those other foams fit.

Both rick Cobb and Tom at myaudioaddiction have the correct surrounds for these and both suggest using the test tone for centering so you don't have to get into the dust cap and coil. I have had nothing but great results with that in my other refoams.

Btw, these all tested good at 2.8- 3.0 ohm

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my 58S woofers have the same fiberboard ring, IIRC....I've had the best luck cleaning the edge of cones up with new single edge razor blades, like a paint scraper uses....

as far as the woofer appearance.....dry, stiff paintbrush. another thing I've done on occasion is to use supergle to "paint" the woofer cone....that usually blackens and stiffens the cone without adding much, if any appreciable mass

another option is to "color" the cone with a black permanent marker (again won't add any appreciable mass), or use some black spray paint, holding the can18"+ away from the cone and lightly mist it in multiple steps

do any of these coloring/ cone treatments before refoaming

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The masonite ring should be there. I agree with michiganpat on clean up. If the old dried glue is a hard type like Aleen's I've used sandpaper to remove high spots, otherwise exacto knife works well for me. I use a mag-visor to do my work (but I have poor eyesight).

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Hi David,

Yes, the masonite ring indeed is original, so please do not remove it.

I have worked on a woofer before where the foam surround was only replaced a few years earlier.

All I can say is lots of patience and take your time.

I once cleaned a woofer where it was plastered with glue/tar.

It took me a long time, not 100% but clean enough.

David

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Okay, good to know about the ring. I look forward to seeing how the new surrounds sit on that.

As far as cleaning those dirty cones, I have already done the paint brush and vacuum process.

in ordering the surrounds I am going to get the mid woofer surrounds in on the same order. Were there 2 versions of the mid woofer that were used on the 9's and are the surrounds therefore different? I have seen photos of AR9 midwoofers with a seam in the cone and mine and others do not.

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I've used highly diluted pva glue -- watered-down matte finish Modge Podge -- on cones before but sounds like you are interested in the cosmetics. Others have used watered down black acrylic artist's paint which I haven't tried. It may be a challenge to remove rust stains without damaging the cone material. I imagine these cones are fairly stable though. If they are water-stable I might be willing to do a spot test using Naval Jelly with a water rinse before resorting to paint.

Roger

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I would much rather not paint them. Cleaning would be my prefered step and actually even if they don't come entirely clean I am still not sure I would apply any sort of painted on substance. The markers option would seem a best option rather than coating them if anything. That's just my instinct.

What the heck is Naval Jelly? I gotta look that one up.

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Okay, good to know about the ring. I look forward to seeing how the new surrounds sit on that.

As far as cleaning those dirty cones, I have already done the paint brush and vacuum process.

in ordering the surrounds I am going to get the mid woofer surrounds in on the same order. Were there 2 versions of the mid woofer that were used on the 9's and are the surrounds therefore different? I have seen photos of AR9 midwoofers with a seam in the cone and mine and others do not.

Like in the attached picture? (the one on the left)

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According to the records in the Library that driver (#200450B) was for the AR9LS and 98LS (drwg #171 revB, drwg#076, rev A was stamped obsolete) The difference I could see was the surround was glued to the back of the cone and it was on mine. These came out of an AR94 and were commonly used in that speaker; and they could have found there way into other speakers. Upon Roy's suggestion I glued the new foam onto the top of the cone lip as the original glue used was very sticky and proved very stubborn to remove. I had to cut a shim/gasket and add it to the basket so the surround would sit correctly. Same foams as far as I know. I believe I was told that there is now only the two styles of surrounds: The grey and the black ones; and that an 8" AR surround will/can do all AR 8" drivers.

The correct driver number for the AR9 and 90 Lower Mid is #200027-0

I have a friend who has late model AR9s and the LMR is #1210043 - 08

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Does black coned woofer use seamed cone? Seam like straight line is visible in the picture. Not very usual design for these days...I wonder why?

Best Regards

Kimmo

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Here's an attached picture of the drivers completed and a picture of the grey and black surrounds. They are made by different manufacturers. I'm not sure if they are both polyether or not.

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Here's an attached picture of the drivers completed and a picture of the grey and black surrounds. They are made by different manufacturers. I'm not sure if they are both polyether or not.

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Possibly not relevant to this discussion of the AR-9 lower mid-range driver, but the 8" AR woofer shown here appears very similar to the black-cone (with seam) driver that DavidR showed on the left in post #10. This driver is p/n 200050-0, dated late 1983, and is the woofer from the AR-28B. In the pic attached, the paper cone seam is clearly visible to the right of the dust cap. The foams used here fit just fine, and like the original, I placed the inner foam lip under the outer cone edge. If you look closely, you can see where I cut and re-glued the original mesh dust cap after shimming.

For DavidDru, naval jelly is a mildly caustic goop which can be very effective for removal of surface rust.

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Eminence has used seamed cones for their "retro/vintage" guitar speakers for years... I suppose that this is more for looks, as conventional "molded" variety cones should be better... that is why I wondered why this design was used...

Best Regards

Kimmo

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Made some progress on the 4 woofers this weekend.

The dirty condition of the cones was really bothering me and few were comfortable recommending to me to clean them with anything other than dry process' etc. The flanges were also ugly with some pretty good corrosion and on one of them pitting and rust. See earlier photos in the thread.

I reached out to Roy to get his take considering he works on drivers a bit. :D Based on his thoughts I went ahead and used a light amount of rubbing alcohol on the nasty areas of the cones. Used a soft toothbrush in a few areas where stuff was literally splattered on the paper and followed up with a light wipe with a microfiber rag and rubbing alcohol. My reasoning was that these had already been exposed to whatever got on them so if there has been any damage, it has already been done. Of course, the alcohol drys very fast so if the paper got wet, it didn't stay wet very long. Results are good and it did not take much to get most of the residue off so I was able to limit how much alcohol and wiping I had to do.

Okay, you can breathe now. And hope along with me that I did the right thing. :rolleyes:

As for the flanges, I painted them. Roy said he paints them black all the time so I went down the same road. He suggested just some simple paint from Michaels or wherever but when I went to Ace Hardware I looked in their paint area and found a metallic Aluminum color that is a near match to the original so I went with that.

Now on to the refoam. Hopefully do the cone side tonight.

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Hi David,

Nice job !

When I refoamed by AR9 woofers or any other woofers, I always check and make sure that the spiders have not sagged too much.

On a few occassions when they have, I have used the hair dryer method to reduce the sagging.

I turn the woofers upside down, weighted the cone so they are moved away from the magnet slightly from their sagging position.

Use the hair dryer at medium heat setting and warm the spiders up for a few minutes moving around constantly (Not hot enough to melt the glue).

Keep the weighs on and leave them to cool.

This is not 100% but has helped to reduce the sagging.

Just my 2 pence.

David.

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Sorry !

The way I used is simple but works for me.

I use some long thin wooden/plastic coffee stirrers, push them through the gaps in the basket.

Once that is done, join the stirrer ends to form a grid pattern and secure with sellotape.

Put just enough weights on the grid to weigh the cone down.

This is what I used but sure that other experts here must have better ways of doing it.

David.

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Given that preserving the fiber integrity in those old paper cones is in my opinion job 1, I don't approve of putting anything on them, unless there are sonic-harmful deposits to remove. And I shudder at the thought of Naval Jelly.

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Given that preserving the fiber integrity in those old paper cones is in my opinion job 1, I don't approve of putting anything on them, unless there are sonic-harmful deposits to remove. And I shudder at the thought of Naval Jelly.

Yes, water on paper may be an issue... Naval Jelly on the metal wouldn't be a problem.

Roger

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