JBL 116H Woofer

[natenkiki2004]

I had another thread on here asking about L19 mods and crossover work. But before I got to that, I had to install new surrounds on the 116H woofers. I bought a kit online a couple weeks ago and installed it. It was great. I loved the sound from these L19's, until I ran a 15-30hz signal with Sinegen. I used the speakers for less than a week and didn't blast them in my small room. With a 15hz tone at listening levels, rubbing could be heard in one of the woofers. Turn it up a bit and the other one would start rubbing too. Long story short, I broke down and bought another kit, this time with shims. Yesterday I took several hours to remove, clean and prepare for the new surrounds. In the process of removing the first pair, a thin layer of paper came off the cone where the surround was attached. The cone was still sturdy and didn't show any weakness so I continued. Last night the first woofer finished drying. I hooked it up to the crossover and then to my amp and tried the 15hz tone again. My heart sank, it rubbed at listening levels AGAIN. Even after using shims. Today, I got the other woofer hooked up and it's perfect. I can go way past listening levels with 15hz and no rubbing.

I don't know what to do at this point. I'm unsure if the failed woofer can handle another surround without a new cone. I don't know if the woofer is damaged even. I got the speakers free from a buddy who got them from someone else. It's possible they were used with missing/damaged surrounds. Does this sound like the woofer is damaged or do I just totally fail at gluing new surrounds on? I used a total of 8 shims all the way around and the cone was solid and could not move up or down so I'm pretty sure I did the shims right. I can push on a part of the surround and make the rubbing go away. I was thinking of gluing something in place to keep pressure on it and MacGyver-fix the woofer. From what I've read, re-coning a woofer is harder and more expensive to do. Would it be better to purchase a refurbished 116H woofer to pair with my working one?

I'm really open to any suggestions. I've already poured $50 in refoam kits into these speakers. I still have another $50-$100 for the crossovers to do. It would be nice down the road if I sell these to have made a profit on them or at least break even.

[grumpy]

1) wondering what "listening levels" at 15Hz are ... even 30Hz is below port tuning
so should be used sparingly (i.e., low enough level to not cause over-excursion of the
woofer).

2) shims or not, if the spider isn't symmetrical and centered, you could have a problem
(the shims could just temporarily tension one side and compress the other, since the outside
of the spider is still glued to the frame).

3) it -might- be possible to -not- use shims, but instead a 30Hz tone while gluing the surround,
to compensate for the rubbing tendency...(slightly eccentric positioning to pull)
not as optimal as a recone, but if you are able to reuse a surround, it costs nothing to try.

4) someone else's resurround or recone job might be less costly than a full-on new JBL
recone, but obviously involves a level of risk...

[natenkiki2004]

Listening levels would be the range that I would watch a movie or listen to music at. In-between quiet and loud. The kit from Rick Cobb (I didn't order one from him) comes with a 30hz test tone. I used both 30 and 15hz. I figure that if it's centered, it shouldn't have a problem doing 15hz for larger excursions. I did notice that with shims on the first woofer (the one that failed to be center) I could actually make it off-center when I was trying to lift the cone as-per instructions in my kit. On my first kit, I did try without cutting the dust cap and I used a low-volume 30hz tone and it was fine but turning up the volume after they were dried and installed, it rubbed on both 15 and 30hz. Am I just being over-concerned with this? I realize long excursions aren't part of daily life for the woofer but there shouldn't be ANY rubbing at all should there? I also realize that by dropping cash on someone elses refurbs I could land myself in my current position with more wasted money. I'm halfway tempted to just buy some 8" Dayton woofers (I heard somewhere that the classic line is an "ok" substitute for JBL woofers) and be done with it.

Let's just say that I go ahead and use these woofers, the one rubs on long excursions but it doesn't sound like it rubs on short excursions. What's the worst that could happen? Blown woofers? My Sony ES amp has a protection circuit so if the woofer shorts out the voice coil, that should kick in and prevent damage to the amp. So, worst case, I blow the woofers and have to replace them? That's kind of what I'm tempted to do now, just buy new woofers.

[grumpy]

right. so at 15Hz you really shouldn't hear anything... these are not meant to play that low.
that was my concern, keeping in mind that large excursions for a 116H is not much (<5mm)

there should be no rubbing at that level, beyond that the transducer is being over driven
(not hard to do).

[natenkiki2004]

I loaded up a hollywood video and played it with just that woofer. I'm a littler concerned that it moves enough to rub on loud listening levels. I'm debating whether I should just use them as-is and hope that they don't damage themselves or attempt to redo the surround and risk damaging the paper cone enough to warrant a re-cone. If the woofers rub enough to short, won't the protection circuit in my amp kick in and eliminate damage to the amp? I would then just have to buy a new woofer, worst case scenario?

[grumpy]

Maybe... Personally, I'd figure out a path that repaired or replaced the driver... Taking it easy on HT use until then.

[natenkiki2004]

I think I'll try round 3 at re-doing the surround on it and hope that it doesn't hurt the cone any more. If it damages the cone too much, I'll see if anyone here wants to bother re-coning it or perhaps putting it up on eBay and then finding a replacement 116H from a reliable seller (or here too).

[natenkiki2004]

Well I carefully peeled off the surround from the basket and figured I may as well try to re-glue it and pay careful attention to the whole cone and centering everything. It just dried and it does rub still but at 1-2 oclock which is above my listening range and since a 15hz tone isn't typical listening, I'm going to call it good. Time to focus on the crossovers!

[Audiobeer]

Well I carefully peeled off the surround from the basket and figured I may as well try to re-glue it and pay careful attention to the whole cone and centering everything. It just dried and it does rub still but at 1-2 oclock which is above my listening range and since a 15hz tone isn't typical listening, I'm going to call it good. Time to focus on the crossovers!

I have a pair if your interested, I could send to you to evaluate and see if it improves your experience.