BillFitzmaurice.info

Well, it has been 10 years since I built my air of BP102 loaded 20" T39s and I decided to check them out. I had never put full power to them nor did full sweeps because, back then I had to burn the midnight oil to get them completed on time, and the few times that I did use them it was for lower volume events. I did have them running near full tilt with a pair of TLAHPros, outdoors, a couple of months ago, for test and tune, and, I did notice that something seemed to be off with the subs. So, a few weeks ago I started at 40hz, gently cranked it up until I was near 30v. The first sub had air leaks at the Speakon connectors that are installed in the mouth. I pulled them out, applied a goodly amount of hot glue in and reinstalled. That took care of the air leaks. Yay!
The next sub had a nasty rattle at 40 hz with 12v applied, or 50hz with 18v. I could get it to rattle if I wrapped #5 panel behind the driver so, I figured I must have a loose brace or two. Multiple holes were drilled and eventually I found the braces. I drove 2" screws to lock in the braces, installed the driver, ran the test, and.... it's still there. Now what!? Well, I thought of a member from a long time ago... Harley Dear. So, out came my hand saw

Then, it was time to cut the side panel free.

Everything seemed fine except for this jumper, so I glue in a small piece of foam underneath.

That was not the answer! I found some gaps in the small braces so I applied adhesive on any brace that I could find, and the retested. It doesn't rattle until I hit 27v. I am happy with that. I had it going at 50hz on 27v and my wife about 50ft away, in the house, and she said it was too much and hurting her ears (she IS sensitive that way).

I should add that those two cabs are the only two that I never really tested. All the other cabs that I have built were stress tested to make sure that they would perform properly.

First time I've ever seen the boards "Active Topics" go blank from inactivity since I've been a member here. Tom to the rescue! An enjoyable read I might add. I've always wondered how to get the side off, never thought long enough to think of using a hand saw. I don't think I've seen one in person in over 20 years! Great job Tom. Bummer it didn't get completely resolved, but sometimes good enough is good enough. Well done brother.

Did you remove the covers and check the drivers? I'll bet they can be tightened after 10 years. Plus, this happened to me and my driver was shredded. It worked at low volume, then started farting out with more power.

Indeed, I did Bruce. It was because of you that I thought that I should check the screws on the drivers. The screws did move a titch.

Seth wrote: ↑Sun Sep 28, 2025 10:13 pm First time I've ever seen the boards "Active Topics" go blank from inactivity since I've been a member here. Tom to the rescue! An enjoyable read I might add. I've always wondered how to get the side off, never thought long enough to think of using a hand saw. I don't think I've seen one in person in over 20 years! Great job Tom. Bummer it didn't get completely resolved, but sometimes good enough is good enough. Well done brother.

Thanks Seth! I try!

That was a good read. Thanks for sharing.

Joman116 wrote: ↑Tue Sep 30, 2025 11:58 am That was a good read. Thanks for sharing.

You're welcome!