Just refoamed a pair of RL-140's 2 days ago. Used standard 6" rings with an angled lip, not flat, and it worked perfectly. Just opening those speakers is a pain. Lay then down on a soft carpet face down. There are 10 long screws along the frame, and 9 smaller silver screws throughout the back of the speakers. Four are clearly visible. Four will be visible when you remove the nylon ribbons that wrap around the speaker. They are "under" there. The 9th is also visible near the wire terminals.
After taking all these off, you will have to carefully work the 2 halves apart. They're on pretty tight even without screws. When you get it lose, you'll need to lift the back panel up enough to reach under there and disconnect the wires that are attached to the speaker spring terminals. Keep an eye on the wire orientation.
The inside of these speakers is pretty amazing. Looks like a mouse maze, along with mouse beds, which are foam sound insulation blocks. You only have to move them out of the way to get to the 2 woofers.
Carefully unplug the wires that are connected to the 2 woofers. Again, keep track of + and -. The woofers are held down by some funky metal channels. Four of them are screwed down to "pinch" each woofer basket in place. Remove these, and you will then be able to pull the woofers out. They might be stuck a bit, but they will come out.
Prepping the speakers for the new foam was the biggest pain for me. Remove all the lose rotted foam pieces from the speaker. You then have to carefully remove the fiber spacer ring first by carefully running an exacto blade several times around the entire ring to be able to lift it. You will have to reuse this ring so be careful not to mess it up! The blade will get fouled
up by the rotted foam and you will have to keep cleaning it with acetone or it won't move.
Once you get the ring off, then it's time to clean up! Remove all of the gooey mess from the basket and very carefully from the speaker cone. You can scrape it off carefully with an exacto blade too. You can then clean it all carefully with denatured alcohol. I even used a Dremel with a small brass brush to get the basket part totally clean. Be careful with the cone! I then used this stuff called Pliobond contact cement to glue the new foam to the
speaker. Attach the cone to the inner lip of the ring first. If you did a good job of removing the crap from the cone, you can actually see a nice clear ring where the original was glued. With a small brush you can carefully "paint" on the glue on the cone. Then carefully coat the inner lip of the foam ring. Once the cement was tacky, I then laid the foam ring into the fiber spacer to help me center it on the cone. I pushed down on the cone a little so the two
surfaces wouldn’t make a lot of contact to keep them from bonding . Then carefully placed the spacer with the foam ring on the basket, and slowly let the cone up to make contact. I kept checking that there was no rubbing in the voice coil while pressing on the foam ring to get a good seal. Go all the way around several times making sure you have no gaps. Use pressure instead of dragging or you can accidentally pull the cone off center. Once it's
completely glued and smooth, leave it for at least a day to dry before you move on to the outer lip of the ring. Before getting started, I raised the cone a bit by using cardboard spacers to lift the cone up slightly by wedging them between the cone and the basket. Again, be careful you don't raise it too much! Just enough to make it a bit easier to brush the cement on both surfaces (the cone and the basket. Again carefully brush on the cement on
the basket surface that will contact the foam ring. Make sure you get the entire surface covered with a decent but not too thick coat. Move onto the foam ring, again making sure you get the entire ring’s outer lip. If you get some wrinkling, don’t worry, it will smooth out.
Wait till the cement is a little tacky as before and then remove the spacers. The cone will lightly drop and the foam will make light contact with the basket. Pliobond is pretty forgiving. It won’t bond to the point that you’ll have to rip it off if make a mistake. Instead it will wait until you apply pressure on the foam. Checking for voice coil contact in this step is even
more important. Just let the cone center itself, apply pressure to the foam in one area, and check for coil contact. If there’s no contact, then apply pressure in another area of the foam, and so on until the entire outer ring is bonded. Continue applying pressure to make sure there’s a firm and complete bond.
That’s it! Again, wait for at least 24 hours before you assemble them , and another 24 before you try blasting them. They worked perfectly for me. Unfortunately, I am totally spoiled by ADS speakers and the B&O’s didn’t impress me at all. They are ok, but when you hit that A/B switch and go back to the ADS’s, the L-810’s blow them away, as they do so many other
speakers I’ve A/B’d.
Good luck!
Great advice, and well done. I'd like to add a couple things though (I once worked in a B&O authorized service center, and I've done a few Redlines before).
While the woofers are out, take the time to check and see if any of the dead foam has gotten in between the grill cloth and the baffle. The grill cloth is a really stretchy fabric, so it will be possible to fish that stuff out of there, especially if you have a really narrow vacuum attachment. If you leave it in there, it will show when the speaker is reassembled, since the cloth is stretched tightly over the baffle itself.
These are not-so-obvious things I either learned the hard way, or with the guy I was working for giving instructions over my shoulder:
1. Find some way to mark which end of both shell halves is the TOP. Trust me on this. Almost every screw will fit with it on the wrong way, and you may not notice until you have almost every one of them in.
2. If you haven't already taken everything apart inside, mark each wire to the exact terminal it should connect with. B&O seems to be very fond of odd color codes. Also, the + and - markings on the inside of the back shell are not always easy to see, even in good light.
3. Before putting everything back together, check the screws that hold the tweeter, and any other drivers, to make sure they are still tight, and haven't lost tension over the years. You'd be amazed at how many people think that their tweeters are about to die, when the only problem is that the mountings are loose.
4. DO NOT torque the shell screws down too tightly. They WILL strip, as they seat into plastic, not metal or MDF.
5. If you are still lucky enough to have the straps intact, putting them back on is the most likely time that they will be damaged. Work them gently over the shell, make sure that they are seated in their groove all the way around, and then start tightening the screw slowly, and make sure the strap stays in the groove as you go. Now, given what I said in #4 above, this is the one time to not chicken out! Tighten the screw slowly until the plastic block is fully seated into the case. Yes, you are going to swear that the strap is about to explode, it fits that tightly! Just remember, that was where the strap block was when it started, so it WILL go back if the shells are mated properly. OH yeah, the RL140 logo on the strap goes on the bottom, on the left side of the speaker, in case you forget.
6. After the straps are back in place, make sure all the shell screws are still seated firmly.
Good luck!
:thmbsp: