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Old 05-29-2014, 10:50 PM
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steve_amestoy steve_amestoy is offline
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Sealed box around Free Air Sub

Has anyone ever built a box around there stock JL sub? I have a 06 Star with a wetsounds FA 10" sub in the stock sub location. I don't really want to put a sub up in the port side storage. I thought MC made some kind of box you could put around the JL subs back in the day. If anyone has done this can you give me some pointers and maybe post some pics. Thanks.
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Old 05-30-2014, 10:45 AM
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David Analog David Analog is offline
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Placing a 'true' infinite baffle subwoofer in a small sealed enclosure is something that you just don't do.
Every woofer, and enclosure for that matter, has a range/application in which it can be a linear and faithful transducer. When applied outside of that range/application the performance becomes extremely poor.
There are quasi/pseudo IB (infinite baffle) woofers that can be placed into a small enclosure but these 'jack of all trade' woofers are not very good IB woofers to begin with.
The JL Audio 10" IB woofer is the real McCoy. It has a high 'Qts' (free air damping) of .8, and when used in an enclosure from 2.25 cu.ft. to infinite the 'Qtc' (system 'Q') and resonance remains constant with the free air parameters. The IB woofer is nearly all self-damped via the correct combination of moving mass, compliance, motor strength, etc.
A typical AS (air suspension) 10" woofer might have a free air 'Qts' of .45 and when placed in a .6 cu.ft. net enclosure the system 'Qtc' might raise to .8 along with a significant increase in resonant frequency. In fact, once the AS woofer is placed in a small sealed enclosure its loaded parameters (Qtc & resonance) will be very similar to the correctly applied IB woofer. Thus, a true AS woofer is highly dependent on the small volume of trapped air in the sealed enclosure for its damping.
Here's the less technical analogy....don't place the shock absorbers from a 3500 truck on a 1500 model because it will ride like....
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Old 05-30-2014, 11:15 AM
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So would you say the wetsounds 10" FA is the real Mccoy also and leave it be?

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Old 05-30-2014, 11:56 AM
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Quote:
Originally Posted by steve_amestoy View Post
So would you say the wetsounds 10" FA is the real Mccoy also and leave it be?

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Yes, the Wetsounds 10FA is a real and very good infinite baffle woofer based on its high .6 'Q' and from what I have personally heard when correctly powered and installed.
The JL Audio IB is my infinite baffle woofer of choice. But if you are not satisfied with either the Wetsounds or JL Audio as the top two, then you have to go larger with more power in an air suspension or bass-reflex woofer that is intended for such an enclosure. However, you might go backwards a step when you go forward with something a bit larger, as in going from direct-radiating to a woofer/enclosure that is playing or vented from a concealed compartment. In other words, if you make that step, make it a significant one.
Another option if you have the available surface area at the existing mounting location, is to wait for the new JL Audio IB 12-inch that is coming later this year. With a 4-inch voice coil and matching motor structure, this new sub is an absolute beast. And you would need more power.
Beyond that, it really helps to use someone like Odin at Earmark Marine as your equipment source. He walks his customers through all the finer details of the installation execution, and in particular system tuning, that can have a major impact on the final performance. He can get you more performance from the same gear. Odin's sound engineering experience is off the charts but he can also dumb it down if you don't have much tolerance for the highly technical.
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Old 05-30-2014, 12:29 PM
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I put a sealed enclosure around the back of a stock IB sub amd was quite impressed with its performance after increasing its power to 375wrms. really big difference to running it infinite baffle. After I blew that sub I put in the non-IB sub and it works even better. I still have an spare IB sub to put in there when I blow the non-IB sub until I can get a replacement. we run them pretty hard but just love the output from these little 10" subs.
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Old 05-30-2014, 12:40 PM
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Originally Posted by craig3972 View Post
I put a sealed enclosure around the back of a stock IB sub amd was quite impressed with its performance after increasing its power to 375wrms. really big difference to running it infinite baffle. After I blew that sub I put in the non-IB sub and it works even better. I still have an spare IB sub to put in there when I blow the non-IB sub until I can get a replacement. we run them pretty hard but just love the output from these little 10" subs.
Sure, an IB sub in a small enclosure can give you a pronounced peak in the upper bass and sound very 'live' at the cost of no low bass. Technically that IS more output even though it's over a narrower bandwidth. But it sounds terribly unnatural to me. And because you have narrowed the sub's bandwidth considerably, to compensate many would be tempted to push the sub harder with more low frequency equalization, thus blow the woofer.
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Old 05-30-2014, 01:23 PM
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I think the last sub (M10W5 - enclosed sub) failed due to spider detachment, the one before that had the plastic chassis crack and break. We run the system wide open for extened periods - party stereo
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JL is great with warranty - all have been warranty repacement.
I guess what I am saying is if you want to build an enclosure for the sub, it will sound marketly better than the IB senario that it is currently in. It may not be the best situation, but at least you can give it a try to see if you like it without the cost of having to purchase a new sub and cutting up your boat. Dont forget, it will need at least 250wrms.

Last edited by craig3972; 05-30-2014 at 01:58 PM.
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