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      12-11-2012, 06:12 PM   #67
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Drives: '08 335i
Join Date: Jul 2008
Location: JAX

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Originally Posted by makkan00 View Post
Very interesting. I always thought that IB sub would die due to mechanical failure. But you pointed out that it is thermal failure which can cook the sub in IB installation.

I looked at your graphs. Couple of things are very intersting especially results for AE SPB 15. Also results for 12W7 are very promising...

As you simulated it in a big box and I wonder with the trunk + windows open (no resistance), would a driver reach its xmax that could lead to mechanical failure?
OR am I extra careful...?

I have tried to look at Pe rating for 12W7 but could not find it on their website....any idea? or Shall I consider its 1000W RMS as Pe?
There already is very little damping with the trunk volume simulated at 16 ft3. With the trunk open the xmax basically stays the same, and the output just drops a little. The program I believe assumes a true IB environment on the front side of the cone, so modeling windows up and down does not work.

When I smoked the VC on my sub yesterday I was using a 30Hz subsonic and the program calculated a max. excursion of 16 mm, which is also the sub's xmax, and I can vouch that the sub was playing linear at the time, so the program I think is very accurate and reliable for that. Your 12w7 has a Pe of 750W I believe so giving it 1000W could be problematic. If I were you I would do the JL gain setting technique in order to avoid sending it more than it can handle. My Infinity did not give me any audible warning before I smelled burnt metal and at that point the sub is already toast (pun intended) so be careful with that very expensive sub of yours! If you want to be extra safe I would say get a JL 750/1 amp, since that's all the power you're ever going to need anyway.
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