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      12-06-2012, 08:00 AM   #31
Mr Singh
United Kingdom

Drives: E91 330D M Sport Auto
Join Date: Oct 2011
Location: Milton Keynes

iTrader: (3)

Originally Posted by makkan00 View Post
I am not satisfied with Alpine Type X sub. It plays lower frequencies better if frequencies <50Hz.

I have been looking for a better IB driver. I had a discussion with Kaigoss here.

I am considering two drivers JL 12W7 vs Fi IB3 12

Now looking at their specs here is my judgement and score of each

__________________JL 12 W7 ----VS----------Fi IB3 12----------winner
Fs:_________________27.2Hz -----------------23.6Hz-------------Fi
Qts:________________0.482 -------------------0.57-------------JL in my case
Xmas:_______________29mm------------------ 30mm-------------none
Efficiency (1W/1m)____ 86.2 dB------------------83.2 dB-----------JL

My explanation to these:

-Fs: Surely Fi wins and can play lower than JL.
-Qts: For IB ideal 0.7 Qts. If you start adding anything in the boot, Qts will start increasing. My boot is mostly hal full so with Fi sub, it will start to roll off sooner (as explained by John). John also explained that with lower Qts, less power will be required for the driver to reach its max xmas.
-Vas: it should be 10XVas for IB or minimum 4XVas. So if you calculate, JL 10X Vas will be closer to BMW boot space.
-Xmas: difference of 1mm is not significant.
-Efficiency: JL seems more efficient.

So in my perception and going by the attributes on the papers, JL wins it by 3:1.

If a person keeps car's trunk empty and if Fi wins Qts in that case, then the score is 2:2.

Well both of them are good drivers, but I am going to try JL on this occasion.

In an IB application you can fully expect the bandwidth to excel from 15-45Hz. Above this things do and will roll off quick. Its very important to have strong midbass in IB installs. You won't have stong upper end response like you typically would in a sealed enclosed setup, therefore midbass is paramount to ensure good transition in your setup.

As for your judgement scores, you are comparing 2 very different drivers for 2 VERY different intended applications. Take the efficiency readings with a pinch of salt and read up about Hoffmans Iron law. The ratings on power handling are also somewhat off, Fi rate the IB3 based on mechnical power handling not thermal. Thermally that thing will take twice the rated power but in IB drivers the mechnical limitations are primary way of giving ratings.