Help with my old pair of JBL LX500 speakers

[JohnnyBluRay]

This is a pic online of the JBL LX500 i own.

I havent used them the past 2 years. Tonight i hooked them up but i saw around BOTH woofers the material around the speaker tearing off, almost disentegrating. I need advice on either replacing both woofers OR just buy new latest pair of floorstanding speakers. Please help. Thanks.

[HDJK]

Originally Posted by JohnnyBluRay

This is a pic online of the JBL LX500 i own.

I havent used them the past 2 years. Tonight i hooked them up but i saw around BOTH woofers the material around the speaker tearing off, almost disentegrating. I need advice on either replacing both woofers OR just buy new latest pair of floorstanding speakers. Please help. Thanks.

I don't know what this is called in English (it's called 'Sicke' in German, it's just the surrounding of the driver). You don't need to replace the whole woofer, just have a professional replace the 'Sicke' and you're set.

[HDJK]

According to Wikipedia the 'Sicke' is just called surround.

[jon s]

This is not uncommon, the foam surrounds used on many speakers disentegrate with age. It's worse with high humdity. That's why I do not buy any speakers that uses foam for the surrounds, insisting on drivers with butyl rubber surrounds (that's why Polk has always used butyl rubber). Foam is cheaper but is not durable.

The foam surrounds can be user replaced but will take some skill in aligning the foam perfectly centered otherwise the voice coil can rub and short out the speaker. foam kits can be found at Parts Express. Otherwise you will have to buy a replacement woofer from JBL.

[Beta Man]

http://www.newfoam.com/


They will sell you a kit (about $30.00), based on the dimensions you give them on a form (available at their site), which includes shims that fit into the "groove", virtually guarenteeing a proper alignment. This method requires that you cut the old dustcap, and replace it when you're done. They include the dustcap, rings, shims and glue and offer a video walking you through the process.

The only difference between the method outlined below and the newfoam method is cutting the dustcap and using the shims. You will not have to do the alignment steps using shims.

If you're more adventurous, the method below is not only much cheaper (10" rings are $1.50/ea at MAT Electronics, and to me seem exactly like the newfoam ones), but also do not require you to cut the dustcap. MAT Electronics has a $25 minimum order, so for roughly the same price as one pair from newfoam you get a bunch of rings, or other stuff they have.

1) Clean off the old foam. You might have to use a knife or scaper to remove the gasket first. Place the gasket off to the side, you'll need it later. On the cone, you can usually rub it off with your fingers. On the basket you can use a small scraper and even solvent, it's metal. Don't worry about perfection, just make sure the loose stuff is off. [Note: The better you clean the old foam off, the closer to original the finished product will look. It won't effect the sound. I personally aim for the finished product to look at least 85%. If you destroy the gasket during removal they have generic gaskets at MAT.]

[If you are using shims cut the dustcap off now and install the shims.]

2) Check the new rings for fit, then glue the new ring to the cone. I use Elmers glue. I apply a bead of glue to the cone, place the ring on, then remove it and let the glue "set up" for 15-20 minutes. It is generally better to use too much glue than not enough - it dries clear. After waiting for the set up (the glue will get tacky to the touch), place the ring back on and center it. Let this dry till the glue is clear, at least 2 hours. While it's drying keep an eye on it, make sure it's stuck down firmly.

[Note: I personally will lift the unglued basket side of the ring after the cone side has dried and apply another bead of glue there (the edge of the cone and the ring underneath the roll). I do not believe this is absolutely neccessary, that's just me ]

3) After the glue on the cone is COMPLETELY DRY (totally clear), apply glue to the basket side. This is important, and usually the thing that gets messed up: push the cone down gently, moving it up and down. Make sure it doesn't "rub". Then, again, wait for the glue to dry. It will take longer than the cone side 'cause you can't let the glue set up. Keep an eye on it. Every time you touch it MAKE SURE there's no rub!!

[If you are using shims skip everything related to "rub" or centering the cone, the shims keep it centered.]

There is another way to center the cone. If you have a test tone disc handy (I have Strykes' basszone, but there are many, and there are tones downloadable off the web here: http://www.snapbug.ws/sinewaves/ ), hook the woofer up to an old receiver and give it a LOW LEVEL 10hz tone (SIN010 at snapbug) after gluing the basket side. [Note: 10hz will screw up your woofer very easily if overdriven. Start at zero on the volume, go up slowly, use common sense!!] The woofer should move up and down a little. Feel and listen for rub. I actually move the woofer each way till it rubs, then attempt to center it. After centering it, turn off the test tone. MAKE SURE it's centered before letting it dry. Since you can't let the glue set up when doing the basket side, I usually go back after 15-20 minutes or so and check the alignment again, as well as making sure it's still glued down securely. If you have to press the foam down during the drying process CHECK FOR ALIGNMENT AGAIN. Every time you touch the woofer, check the alignment!!

After the glue dries clear, poof!! You've got a refoamed speaker. Hook it up and see if it rubs! [Note: if you're using the shim method remove the shims before trying the speaker.]

If it does: you'll have to refoam again . Sometimes it's not an option, but it's worth trying. After over 15 pairs I haven't had a problem yet. Once I refoamed a 10" woofer out of a pair of Boston Acoustics' A-100 that had a slight rub when finished - arrgh! I tried "spinning" it 180 degrees and remounted it - it worked (and still works) great!!

If it doesn't: Congratulations, you're an experienced refoamer ! Glue the gasket back on, let it dry!! Be careful not to glue the gasket to the actual roll of the surround. At this stage I also add an additional small bead of glue where the ring meets the cone. [Note: If you're using shims you glue the new dustcap on here.]

Start playing! As you play it it will sound better, there is a break in period for new foam. I run the speakers with the 10 hz test tone at a level high enough to move the cone, again being VERY CAREFUL not to overdrive them, for ten hours using an old receiver before popping them back in the cabinet.

That's it, it's that easy ! And even if it gets screwed up, the consolation is: it didn't work before, either.

[JohnnyBluRay]

Picture of one of the woofers.

Thanks for the help everybody. I called a speaker repair place in OC and they said they can fix it. $40 each. I can do that or buy a new or compatible pair to put in its place. What you think?

[Beta Man]

yep.... needs re-foamed..... if you follow my post above, you should be all-set.

[prerich]

Originally Posted by JohnnyBluRay

Picture of one of the woofers.

Thanks for the help everybody. I called a speaker repair place in OC and they said they can fix it. $40 each. I can do that or buy a new or compatible pair to put in its place. What you think?

Re-foam, those are good speakers, better than the ones offered in most consumer level stores (that was a nice series - titanium dome tweeters). If you can find a third one - run three as LCR that would sound nice !

[JohnnyBluRay]

Always loved the sound from these babies.Thanks all. A third would be nice. Too bad these speakers are not magnet shield friendly. But that could be fixed too.

[prerich]

Originally Posted by JohnnyBluRay

Always loved the sound from these babies.Thanks all. A third would be nice. Too bad these speakers are not magnet shield friendly. But that could be fixed too.

If you have a LCD or Plasma it doesn't matter !!!!!

[Beta Man]

Originally Posted by JohnnyBluRay

Always loved the sound from these babies.Thanks all. A third would be nice. Too bad these speakers are not magnet shield friendly. But that could be fixed too.

Or just give the T.V. plenty of room on each side.... if it's a CRT