ok i finished the spare tire install on my celebrity. It kicks ass i love it. But i think the metal is not tough enough for the presure. There's already small hole in the bottom of it and it's rattling badly. I dynamated the inside. But even from the outside you can see the pressure sucking the bottom of the well in then pushing it out lol. Any suggestions?

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Replies (7)

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ttocs on 04/22/2003 16:11:20
other then welding a brace in place, or actually building a box to seperate it from the metal, I don't know...

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Swez on 04/28/2003 20:31:58
That's new one on me... LOL like ttocs mentioned, may have to add some stiffening members in there to make it more rigid.

Some guys use several layers of fiberglass and epoxy to stiffen things up and stop any resonance issues as well. Other than that, may have to build an enclosure and insert that into the cavity.

Oh yeah, plug that hole as water may get sucked into the cavity. That won't be good for the sub. A bolt and a few fender washers with some silicone to seal it all, should work.

Swez

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schlsux on 04/30/2003 12:18:29
I took a different route. Instead of doing all of that work, I cut 3 ports in it, and flipped the sub upside down. It looks pretty kick ass, and it may not hit as hard but sounds great and saved me tons of work. I already sealed the box in so i didn't want to tear it back up again.
Thanks for the advice though. The holes are sealed, thanks for the reminder.
TJ

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ttocs on 04/30/2003 19:22:52
you cut 3 ports?

I hope that you understand that porting a box is not as simple as putting a hole in a box. If it is not done correctly it can allow too much motion of the speaker and do damage to them.

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Swez on 05/1/2003 08:17:46
Yep, ports have to be designed such to match subs mechanical parameters. If too much air flow is present, not enough back pressure to cool the sub and could damage the sub at high SPL levels.

Ported designs are a bit more involved in design. The larger the ports, the less cone movement will happen and heat can build up in the VC and fry same. If the port size is too small, then tuning to proper frequency target (35-42 Hz) is almost impossible.

Need to rethink your application and do some additional research, if you want to get the most from your sub, but not damage same as you crank it up.

Swez

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schlsux on 05/1/2003 12:01:09
It sounds good. lol. Why would that matter anyway, the whole ass end of the sub isn't even in the enclosure. You can see it when you open the trunk. I'm running it as a free air space sub. Which probally isn't great for it. Like take a sub in a ported box and put it in the wrong way. That's what I did.

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Swez on 05/2/2003 18:42:09
It may sound OK, but if the woofer suspension is not adequately supported by the mechanical design of the spider, surround and magnetic properties of the voice coil, magnet structure... it could easily fail under modest output conditions.

Also, if the suspension is not designed for "free air" applications. damaging the sub is a very good possibility.

I have a thought for you on internal bracing... get yourself a length of 1/2" thin wall conduit. (under $3.00/10ft) Cut them to a length (hack saw) that fits across the tire well, about 3/4 of the way down in the well.

Then, pound each end flat ~1.5" long on either end and drill a 1/4" pilot hole in each flat spot. Now, jam the new brace into your well and bend the flats until you get a good, tight fit. Now run a #10 x 3/4" sheet metal screw into each flat (holes) and attach to tire well. Make 2 of these and run them parallel, on either side of the magnet structure.

Use a glob of silicone seal (as a gasket) between brace and metal well. This will seal against leaks and limit metallic vibration. Once the silcone has cured over night, then reinstall the sub as a sealed design. If you have dynamat in there already... good enough as a gasket... no silicone needed.

FYI: The sub will thank you for this extra work and thieves will not see what you have in the rear compartment. Better safe than sorry OK! If you don't make this change, the sub may fail as you try to push it past the mechanical limits. Be smart, do it right, protect your investments!

Swez

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