Where to purchase surrounds for 1.2tl mid bass drivers?

zumbini

I just picked up a set of SDS 1.2tls for my 19 y/o son from a friend who was the original owner. They came with both SDA interconnects (for common and inverted ground amps) and they are functional, however, the mid bass drivers need to be refoamed, and the grill, corner and side cloth need to be replaced.

I'd like to rebuild these speakers while my son is away at college. (He's a rising sophmore at MIT.) I have the cloth but so far haven't been able to find refoam kits (or just the surrounds) for the mid bass drivers. Do any of y'all know where I can buy them?

agfrost

As stated above, the butyl rubber surrounds should need no attention unless physically damaged (punctured) or exposure to some harsh chemical has compromised the surrounds.

You're a heck of a dad, getting those speakers for your son!

zumbini

My bad. I used "foam" as a generic term for surround.

They appear to be formed from sheets of extremely thin material (probably rubber or a synthetic). They are not rotted, but there are pinholes, punctures and/or tears in amost all of them. (The previous owner had cats....)

zumbini

agfrost wrote: »

You're a heck of a dad, getting those speakers for your son!

Thanks. The speakers were FREE but I drove 200 miles each way to get them.

So, does anybody make replacements for these surrounds?

pitdogg2

None that will be correct. You're best bet is used or buy new from Polk customer service. Tell them you're a club Polk member and get a discount.

zumbini

pitdogg2 wrote: »

None that will be correct. You're best bet is used or buy new from Polk customer service. Tell them you're a club Polk member and get a discount.

Are you suggesting that my only option is to replace all of the mid bass drivers?

zumbini

Here are some photos of the mid bass drivers showing typical damage to the surrounds:

zumbini

Thanks for your reply nbrowser. Unfortunately I'm retired and living on social security. I don't have the funds to replace all 16 mid woofers, so a full restoration will have to wait. I've refoamed literally hundreds of speakers over the last 50 or so years so I'll find some replacment surrounds that are close to the composition and compliance of the originals and make do with them for the time being.

What looks like rust in those photos must be an artifact of the flash because they are not visible upon close inspection. I do see what looks like water spots on the MW cones but I don't think that has affected them. I'll try to get available light photos tomorrow.

The passive radiators appear to be OK, and the cabinet wood and finish is in excellent condition. I have material to recover the grills, corners and side panels so I will probably start working on that shortly.

Thanks again,

Dominick

PSOVLSK

I know nothing of repairing/replacing the drivers, but best of luck to you. I hope you're able to get them working.

F1nut

The rubber surrounds Polk used are unique, there is nothing available that is a suitable replacement. Many have tried and failed. I suggest you buy the new ones, a few at a time as your funds permit. Another idea is to shop eBay for used ones. The stereo driver part number is MW6503. The SDA driver is MW6511.

The drivers should have a uniform shine and be slightly tacky. Water wouldn't spot them like that. I'm thinking mold or something was sprayed on them that has damaged the coating. It's even on the plastic tweeter bezels. Perhaps some sort of cat repellant?

Nightfall

Here's the information to get those drivers replaced. A 19 year old with 1.2's? What a dad! I'd take a shot in the dark, given his age, those polyswitches are going to be put to good use.

Customer Service Representatives are available for telephone orders and general inquiries 24 hours a day, 7 days a week, Pacific Standard Time at 1-800-377-POLK (7655) Option 4.
Technical Support can be reached 9 AM to 5:30 PM, Monday - Friday, Eastern Standard Time at 1-800-377-7655.

P.S. The picture in your signature is a touch too big.

zumbini

Thanks for the part numbers F1nut. Always good to have options.

You might be right about the spots and the use of cat repellent. The original owner has several (cats, not spots ) and noted that they had been attracted to the speakers.

zumbini

Thanks Nightfall. I'll call and get prices on Monday.

Nightfall wrote: »

A 19 year old with 1.2's? What a dad! I'd take a shot in the dark, given his age, those polyswitches are going to be put to good use.

Good call. Zack has had a decent component stereo system since his 13th birthday and he does like to listen to music at concert levels. (He gets that from me....) I added fuses to his last pair of speakers after he smoked a set of small Infinity monitors.

Since I hooked up the 1.2's there's been a steady stream of teenagers heading up to his room to audition them. The music gets very loud for 5-10 minutes and they stumble out with big smiles on their faces. He's driving them full range with a Carver M-1.5t for the time being (375 wpc) but I have plenty of extra amps so they will be bi-amped by the time he comes home from Cambridge for Thanksgiving.

Nightfall wrote: »

The picture in your signature is a touch too big.

I'm trying to figure that out. It's supposed to be a thumbnail linked to the original.

EndersShadow

Hello there man! Nice to see you here, congrats on the purchase for the kid. How his college experience going?

zumbini

Thanks for the welcome Bean. Seemed like this would be the best place to get info on the 1.2tl's.

Zack's freshman year at MIT was a...learning experience. He made some mistakes, and learned a lot about himself, and that's what life's all about. Despite his difficulties he finished with a B+ average so his scholarship is safe for another year. He leaves for Cambridge this Wednesday and he's anxious to get back and do it again.

drumminman

Welcome to CP Zumbini. Replacing all those MW's will cause some financial pain, but if you or your son plan to keep them it's worth it.

In the meantime damage to most of those MW's can be repaired with Rema rubber cement, a cold vulcanizing compound made to repair bike tires. I used it and it works really well. You can read about it here: forum.polkaudio.com/discussion/163519/found-product-for-butyl-rubber-surround-repair#latest

Good luck and keep us posted.

zumbini

Thanks for the link drumminman. I've done that sort of repair as a temporary fix on foam surrounds (and paper cones too) and it's in my budget.

zumbini

BTW: My son Zack is a drummer. He was in a classic rock cover band for 4 years until the oldest members went away to college. (Search for Crossgate Band on Facebook.) He also jammed regularly with a death metal band. Now he's playing fusion with MIT's jazz emsemble. Here's a photo from his Robert Plant look-a-like days:

pitdogg2

Clean the speakers cone and surrounds with Windex and a microfiber cloth or paper towel. Be sure to keep wet or the tackyness of the driver will grab the cloth or paper. Be super careful and use two hands to help support the driver. Many have use this it works well. Spray the Windex on the cloth or paper towel ONLY. Those speakers are a sealed design and any air leakage will affect bass quality. If you can push on the PR and all the MW fall immediately then that is not good for bass.

zumbini

Does it matter which version of WIndex you use? (plain or with ammonia)

pitdogg2

zumbini wrote: »

Does it matter which version of WIndex you use? (plain or with ammonia)

Plain old original Windex with ammonia D is what I have used.

daddyjt

Hey Dom! Funny seeing you here:-)

I found my way over after snagging a pair of SDA SRS. The restoration on these is spendy (I have yet to start mine), but it is nice that the parts are still available.

I can't believe Zack's a sophomore already!

Good luck with the rebuild - I will be watching for tips when I do mine:-)

pitdogg2

True it is but those will run circles around many speakers costing tens of thousands of dollar's. So ask yourself. Is it worth it to spend say 3000.00 to completely restore them YES you'll never buy a pair of 3000.00 speakers that will ever do what these are capable of. EVER!

nooshinjohn

Anyone want do a go fund me page to help out in the restoration?

zumbini

daddyjt wrote: »

Hey Dom! Funny seeing you here:-)

I found my way over after snagging a pair of SDA SRS. The restoration on these is spendy (I have yet to start mine), but it is nice that the parts are still available.

I can't believe Zack's a sophomore already!

Good luck with the rebuild - I will be watching for tips when I do mine:-)

Hey Mark, fancy meeting you here. Gotta go where the knowledge is.

Zack loves his new toys so I'll let him decide how far he wants to take the resto. Meanwhile I'll patch the surrounds, replace the grill cloth, and oil the cabinets so we can enjoy them as they are.

How does one eat an elephant? ONE BITE AT A TIME!

txcoastal1

nooshinjohn wrote: »

Anyone want do a go fund me page to help out in the restoration?

Start it up. I'm game for the cost of a pair drivers. Sounds like we have a proud papa here that wants to do something really nice for a good kid.

zumbini

txcoastal1 wrote: »

nooshinjohn wrote: »

Anyone want do a go fund me page to help out in the restoration?

Start it up. I'm game for the cost of a pair drivers. Sounds like we have a proud papa here that wants to do something really nice for a good kid.

That's very kind and generous of y'all but it's not necessary. I'll do what I can now in the way of repairs and cosmetics, and we'll start saving our pennies. It'll be an excellent father/son project for summer breaks and after he graduates.

nooshinjohn

I'm in for a hundie or a pair of rdo's... Just need a shipping address to send them to.

zumbini

Started with something easy and inexpensive - replacing the grill cloth - and, with nooshinjohn's help, figured out how to remove the side panel.

zumbini

Time for an update:

A few days ago I repaired the rips, tears and pinholes in the mid woofer surrounds using a thin coat of RTV gasket maker applied with a miniature modelers brush after prepping the areas with sandpaper. I did the right speaker first so I could compare them and noted improvements in detail and transient response.





I also wiped down the mid woofer cones with Windex and was able to remove most of the "water spotting" and restore the tacky finish. I'm hoping a couple more wipe downs will eliminate the spots completely.



On the cosmetic side I removed the tattered grills and recovered them. (The grill on the right in the 1st photo had been recovered with black window screen. All the others still had the original cloth.)





I also figured out how to remove the side "accent panels" (they are held on firmly with barbed plastic body panel pins) and I stripped them down to be recovered with the same material. Unfortunately I cracked the wood trim insert on one of them thanks to an extra large blob of glue and lots of extra nails. I glued it back together so the crack is not visible but it's only laminated MDF so I may replace them all with solid oak.







I also inspected the passive radiators as I was concerned that they would also have damaged surrounds but that was not the case.



I had originally thought that the tweeters were all functional but when I isolated them using a 2" mailing tube I realized that T2 and T3 on both speakers were dead. I plan to pull them out today and check the voice coils and wiring. Is there anything in particular I should look for in the way of a failure mode?

zumbini

I measured VC resistance. A working SL3000 measured 5.4 ohm. The non-working SL3000's measure zero. The voice coil leads aren't broken and the solder joints are fine so I assume the non-working tweeters are fried.

working tweeter:


non-working tweeter: