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Do normal compression drivers degrade if left permanently installed outdoors ?
This is assuming the backs are fully sealed, and the horns are angled so as not to collect rainwater.
I'm putting together a system (just for my own use) using some heavy old JBL 2445J drivers, on fairly big heavy horns, and it would be nice to be able to install it and then simply leave it in place.
Some companies do make water resistant compression drivers but even these are not meant to operate with a horn full of water.
Your best bet is to keep them pointed down such that water will run out on it's own should wind blow it up in side.
At work where we sell loudspeakers for outdoor stadiums as well (our synergy horn systems are in about half of the 100,000+ seat stadiums here), we use a metal screen plus open cell foam behind it as a water diffuse, the water that gets to the open cell foam, collects and runs down and out.
Danley Sound Labs
Check Atlas Sound. I have seen their stuff used outdoors in all sorts of industrial settings. And left outside year around.
Yes, they will corrode. The problem is the steel pole pieces/phase plug/magnetic gap rusting, and aluminum corroding. I've seen some badly rusted drivers that had to be scrapped. You can check it every few
years and take a brass wire brush and clean off any rust, especially
in the coil gap.
Thanks. This puzzled me, but then I looked up cutaway diagrams... I had forgotten that the 'anatomy' of a compression driver is reversed from a cone driver - so moisture doesn't have to go through the diaphragm to reach the magnet gap.
I might trim the horns down slightly, so I can mount them them inside something I can seal airtight - 200 litre food drums. That would be less trouble than hauling the horns in and out of storage, and should only cost about $50:
"Food grade steel drums
200lt clean food grade feed or storage steel drums. These drums have only been used once and are in excellent condition. They are a open lid drum with a band clip ring. Limited stock."
Mount the drivers in a bag filled with SF6, a heavier-than-air gas available at a welding supply store.
They won't corrode and loses their HF response.
...didn't Dayton Wright enclose one model of their high power electrostats in a bag filled with SF6 (sulphur hexaflouride)? IIRC, this was done because SF6 is a better dielectric/insulator material than an equal gap of air thus allowing higher polarizing and drive voltage. I also recall that those speakers were quite problem prone due in part to leakage of the SF6.
".didn't Dayton Wright enclose one model of their high power electrostats in a bag filled with SF6 (sulphur hexaflouride)? "
" I also recall that those speakers were quite problem prone due in part to leakage of the SF6."
It's heavier than air, so it wasn't that big of a problem.
A little cling-wrap in the throat and seal up the back of the 2445 and you might be fine without the SF6 (I've done that on floor wedges).
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