Thoughts - JL Audio MicroSub in rear speaker spots

[Chimera]

Originally Posted by toast

That is my pic, and yeah, it was a lot of work. In the end it sounded fine, nice even, but then I made the mistake of putting my fiberglass enclosure for the spare tire well from my STI in there. Just SO much more when placed in the trunk. Some of it is the proximity to the driver and the frequencies involved - you just aren't far enough away and that location doesn't couple to the interior very well.

If you insist on doing it I will give you my enclosure for the price of shipping. It would be good if someone got something out of it.

Nice offer.

[Itsjustjoe]

I've been thinking of building a FG enclosure back there since I bought my car in 2012... never got around to it though, as it will be a ridiculous amount of work for an amateur like me.

Now the $2000 estimate I saw several posts back seems extremely excessive. I'd guess somewhere around $1k for a nice one-off custom enclosure for that space. If someone were to plan a GB for them, they'd probably come down to around $600 ea - but shipping would be really high, pushing the overall cost well above what the vast majority would likely be willing pay. On top of that, the enclosures for the trunk area already offered will almost certainly produce noticeably better sound.


I still might build one (after I finish a few other big projects). If/when I do, I will post it up here, and if there is enough demand, I might consider making a mold so that it could be duplicated. I have to admit, I'm not a pro at this sort of thing, so if I made a few, I couldn't promise high-end, show quality results.


Here's a simple FG enclosure I built to squeeze a 10" sub behind the passenger seat my MR2 without losing any passenger seat legroom or adjustability:

[TOOSTUBBORN2FAIL]

The $2000+ price was for sealed door enclosures for midbass speakers. The rear side panels would be similar in complexity and cost. Trunk enclosures are far easier, and therefore cheaper. Keep in mind a corner loaded trunk enclosure will pretty much always have a huge and sharp peak in response. Some people like this (makes it louder, generally in the frequency range most pop and rap music has their bass), but it's less musically accurate and won't be as clean as other mounting locations. I can post a few measurements to show this tomorrow.

[TOOSTUBBORN2FAIL]

Here are the measurements I promised. This is in a 2014 Kia Optima, but I've noticed similar results in every car I've tried it on, and knowing that a 12" sub can be fit under the glove box in the 86, its very relevant.

This is the measured response of the sub in the trunk corner, and under the glove box in the foot well. As you can see, despite the seat being completely up, the trunk is actually louder. But there is a huge peak of about 8db, at about 28hz. The peak amplitude and frequency will be different in each car, but it will be there. Also notice how ragged the response is, and that it starts to roll off faster than the up front sub. Green is trunk, blue is up front.



But much more telling, is this next set of graphs, the waterfall plots, which show how long it takes for an impulse to decay. Long decay times are THE cause of muddy or "slow" bass. Notice how the up front sub decays much faster than the trunk sub.

Trunk Sub


Front Sub


Listening impressions followed suit. The trunk sub rattled everything, sounded muddy and un-clear. It was louder, but not in a good way. The up front sub by comparison had very few rattles, and was smooth, even with no eq. Individual bass notes were easy to hear.

[DAEMANO]

@TOOSTUBBORN2FAIL

Do you have any info (build thread or pics, etc) of that 12" sub under the glovebox / footwell install you spoke of. There is room down and under there, would love to see it executed.

[TOOSTUBBORN2FAIL]

I'm at the hospital for my mom right now, but the diyma thread recently linked in the on axis speaker thread is the one. He had two subs ran ib, and dropped them for a single stereo integrity mkiv up front.