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All of the JBL square frames have a very small ledge compared to the standard frames. I have done Le-14's, 2108's and 2122's. With Ricks Surrounds they almost self center. If you dry fit the surround and install the retaining ring you can actually play the 30hz disk at low level it will self center.Quote:
Originally Posted by DerekTheGreat
Those surrounds are spot on.
Rob :)
The surrounds we got were from Mr. Cobb. :) They fit really well, although we followed the method outlined by Simply Speakers on YouTube after watching them refoam a 128H, so no test tone. Although I got to wondering if the surround would've stayed stuck to the cone or frame. The glue didn't get tacky for some time (was ~68 in the house) and then when it did, we still went over areas many times, especially on the basket as the surround kept lifting in areas after working the cone up & down like they did. Beginner things, I guess. I think next time I will make the effort to get a test tone going.
I am unquestionably a rank-amateur on this stuff and the pros here will likely laugh or cringe when I show my method. Long and tedious, but I'm done and don't have to work today! ;)Quote:
Originally Posted by DerekTheGreat
Having just done four 128H and two PR300s, I'm wondering what Simply Speakers was thinking about with no test-tone on the 128H.
I find getting just the right amount of glue applied in the first place (don't overdo it) aids in drying and adhesion time. Rick has stopped sending me his 30Hz CD and I can usually remember where I last put one, as well as his glue. I find that the basic Aleene's Original Tacky Glue works for me. It's easy to find, easy to clean-up, gives the right amount of setup time for adjustment, and dries clear. On the LE14H-1 I flip them face-down on a paper towel on my turntable and apply the glue, spreading it out evenly and thinly on the back of the cone's edge with a paint brush. Then I flipped it over, slip the surround in from the front, flip it back over to adjust and periodically go around it to make sure nothing has moved or popped up. I have various sizes of plates and pie pans, determined by the stage of the install and the size of the speaker. Letting the cone hang down (magnet up) helps with getting the surround to lay down but using less glue helps it to dry faster. I have a custom-carved popsicle stick I use to smooth the under-cone edge during drying and then the rounded end to apply a continuous bead of pressure while turning the speaker on the turntable. Once that sets (often overnight to be sure), I flip it back over, run a bead around the thin ledge of the frame lifting the surround with the popsicle stick or paint-brush handle as the glue goes down then, again, spreading it out thinly with a small, stiff paintbrush. That's when I run the test-tone, though there really isn't any movement room at that point. While drying with the tone, I run around the perimeter with the round end of the popsicle stick occasionally. After an hour or so, I turn off the tone, run another thin bead around in the groove between the edge of the surround and the frame using the turntable and then the brush. I install the (clean) retainer ring, then flip the speaker over on a flat surface, face down. At this point the frame and retainer ring will be flush just from the weight of the driver and the surround is not flattened.
But, that all being said, the most difficult part of the assembly was another issue with JBL's T-nut similar to the problem I had with the L150A. This time it was on the mid-bass driver where the bolts had been very stiff coming out. Going back in was worse on two of them and I used a longer 10-32 bolt I had bought to set the T-nut in the L150A just to make sure all the threads were good and the holes lined up. But one nut got stuck and I tried to power it through with my longer bolt and ended up using a claw hammer and brute force just to remove the bolt, nut, and driver in the mid-bass sealed compartment. Moments of panic and thoughts of a bolt cutter crossed my mind. But I was so pissed by then that I went into town in search of a 10-32 SAE tap and found the smallest tap-and-die set at Harbor Freight that had a 10-32 tap. About $19.99 versus just the tap at Lowe's for $7. Now I'm equipped for the duration! I also bought out all of Lowe's 10-32 T-nut stock (6)!
You can see in the photo below my tapping all the T-nuts after that, with the stripped one sitting there for show. The problem nut in the L150a was simply not threaded all the way through and a tap might have saved that. As it was, I tapped all the T-nuts on both 250tis, and several really needed it. I think, in the case of the 250ti, the gasket on the back of the mid-bass driver was installed just enough off to make lining the bolt up at the factory just off enough have cross-threaded the nut without damage to the bolt. At least that's my guess. In any case, the tap did a great job and the bolts didn't need to be run through the die. I guess the factory uses power-drivers to run the bolts in. I use my best Snap-On Phillips hand tool, to make sure I have a good fit in the screw slots and I stop at the least resistance. There aren't that many to require a power-tool and I trust my hands more than my Dewalt in delicate cases.
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What a happy family photo!
Widget
Definitely! Is that a Crown SR-II I see back there???
Did that driver need to come out, the one with the accordion surround? I thought those were good for life? Superb job on your woofers though.
The dude on Simply Speakers seemed like a pro, he was fast and precise. I realized real fast that I'm about as coordinated as a reanimated corpse, yet we still got it done. I don't think we used too much glue, but the tube Rick provides is ultra stiff, I had to glue Angie's surround for her as a result. Aileen's glue, eh? Where can a bloke get some of that? Not that I'll need it soon, but for reference. Not sure how long my 2245's will hold out, they seem ok though. Although I think I'll want to get my 2215's reconed [again] at some point, as I noticed the cones on it do not have Aquaplas on either front or rear. Thought they were supposed to? :dont-know:
Yeah, I bought that Crown just for the 250ti, but I use it on everything in the basement. It doesn't care what I ask it to drive—or how many!!Quote:
Originally Posted by DerekTheGreat
Aleene's makes a full line of glues, most of which are available at any Michael's store, or other craft stores. Not much more than a couple of bucks. I had to order one which is a heat-activated fabric glue I'm going to try on grille cloth that's worked loose on the L112 and 240 before it gets worse. I just need my wife to find her old iron that she'll allow me to use.
No, that mid-bass driver didn't need to come out, I just figured it was easy to do and any weight I could take off would make it that much easier to move them. Glad I did now that I know how badly they F'd up the T-nuts! All fine now.
:thmbsup: