View Full Version : X2 subwoofer upgrade options ?
02-10-2012, 03:11 PM
Would like to do a subwoofer upgrade in an X2. Currently have the free air JL sub that fires directly behind the driver.
Ultimately, would like to keep things as low profile as possible keeping close to a stock look that doesn't scream steal me. Also would like to keep my storage within reason.
Has anybody simply glassed in a small sealed or ported enclosure in the factory location? Basically using the factory hole etc.. but gaining the benefits of a more powerful driver and real box. Seems would be a simple enough solution to gain a good amount of performance and visually not change much.
02-10-2012, 05:37 PM
We often use a JL Audio 10-inch marine subwoofer that has the identical appearance as the factory 'infinite baffle' model but in an 'acoustic suspension' version. It requires a sealed enclosure measuring an external 13.5"x13.5"x13.5". It can be modified into a rectangle or wedge to fit the application as long as the displacement runs consistent. We sandwich the fiberglass wall that the existing IB woofer is mounted into by front loading the woofer and rear loading the enclosure with an airtight rear gasket. Appearance wise it would look exactly like what you have now. Plus, this scheme can be duplicated for more than one woofer.
An 10-inch infinite baffle woofer can perform well if everything is correctly executed with the right wire, correct tuning (crossover/gain selection), the right power, at least a 2.25 cu.ft. of enclosure up to infinity, total front to rear acoustic isolation and a very rigid mounting surface. But factory really doesn't have it completely dialed in all those respects.
There is absolutely no reason that infinite baffle woofers can't perform admirably up to a certain point. However, an air suspension woofer can achieve another level in output for those who want more. But, don't expect a dramatic improvement in the bass until you simultaneously address the amplifier power.
Another option is to run a larger woofer and larger enclosure, whether acoustic suspension or bass-reflex, within the bench seat console and place a vent over the previous woofer opening. The vent allows the bass radiation to freely flow from the compartment out into the cockpit. However there are going to be some losses associated with this approach due to the compliance of the large compartment and adjoining gunnel cavities and the lack of impetus to drive the bass radiation through a comparably small and therefore resistive vent. The woofer in this case is no longer directly coupled to the open cockpit. But, you can offset these losses with a lot of woofer/enclosure size and a lot of power depending on what your personal objectives are...from mild to wild. Of course, the larger the sub system the more storage you will sacrifice.
02-10-2012, 06:36 PM
Would the performance gains from this simple swap and box approach warrant doing this? Or is it better to just jump to multiples and bigger? I know it's in the ear of the user.. I'm not looking to drive the party cove.. but I do know the factory IB sounds fine casually but if you push it runs out of gas quick. I'm looking for something that I can pound on a bit more.
Is the power that inadequate from the factory JL amps? I've yet to crawl in there and see what models they are to check specs.. From their physical size (LOL) I would have expected more. With modern amp technology and power as cheap as it's become I'm shocked that any external amp of would be lacking anymore.
I actually have quite a bit of background experience in speaker design but I don't have any 1st hand experience with boat applications. Most of my efforts these days funnel toward custom home theater and pro sound equipment. I did have a former life many years ago as an autosound installer. Point is that I'm not completely green on this stuff.... but have been out of the know on 12v side of things for some time. And haven't crossed the boat divide yet... Looking to work off the experiences of the ones who have forged before me so to speak.
David I appreciate your insight and experiences..
02-10-2012, 08:42 PM
The JL Audio amplifiers are really good. They're Class AB so yes a little bulky.
The magic power number for the JL Audio IB subs is about 25 percent more than used by factory with two channels bridged into one. Its okay but when you hear maximum sub output in this case you are generally hearing the limitations of the amplifier and the fact that they may have tuned the subwoofer too low on the crossover (as if its in an enclosed vehicle cabin) which restricts the bandwidth and therefore reduces the output which forces the gain up. Absolutely kill any bass boost on an IB woofer. Make sure that the speaker wire to the sub is no less than 16 ga. and 12 ga. would be better. The 4 and 6-channel amplifiers need dedicated 4-ga. supplies and the 2-channel needs an 8-ga. supply. The sub signal path could benefit from more pre-amp voltage and a boost in dynamic range (not a difference in average volume) so a line driver will help. These are all areas to look into and steps that may help improve what you have.
An IB woofer is internally damped for the most part via its mechanical spider and electrical motor structure so its self-sufficient. Its a high 'Q', high resonance driver. The infinite baffle enclosure must be large enough and compliant enough to not impact the 'Q' so the sub isn't very dependent on the enclosure. Once everything is set up correctly to suit this particular sub it will do a great job up to a ceiling. But at some point with longer excursions the suspension, or 'spring' so to speak, cannot maintain its linearity. So it starts to sound lose.
In contrast, an acoustic suspension sub is under-damped and very dependent on the air spring of a smaller and very rigid air mass. As the excursions increase and so does the inertia, acoustic or 'air' suspension maintains better control with a greater output ceiling.
So above are a few things you can do with what you already have to see if its going to make enough difference for you. Soon you'll know if you'll be satisfied.
If you go with multiples, whether infinite baffle or acoustic suspension, it would be advantagous to collect the woofers in a tight pattern with the same or similar orientation so the output compounds a little. Spreading woofers in different locations around the cockpit with different orientations will create phasing issues so that the same woofers and amplification will be far less productive.