Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community - FT86CLUB - Yet another lame'n'boring subwoofer thread ))

Nothing crazy here.. i am 40 lol

Mine is a canadian 2017 brz with a nice sounding system, i still decided to add a nice lil subwoofer to add what the stock system can not give me.

What i wanted was:
- easy project.. better be done in two day lol
- i wanted a front facing driver (usually drive with my rear seat folded down)
- the whole thing needed to be cheap. my budget was 300 which i got by selling exhaust from my former WRX
- securely mounted and sorta auto-x / track days ready. Removable if needed
- reasonably lightweight

Components:
I bought metra type harness connectors not to splice into the signal wires. I noticed some nice non metra branded harnesses (nice thick wires) which i bought. 8ga power wire, 14 gauge wires for signal and sub (i am using 14ga x2 for both positive and negative leads between my amp and the subwoofer.. it would be better to buy like gauge 6 wire but i had plenty of 14 ga wire from previous projects). Other than harness connectors, i had everything else from previous projects

Driver: JL 12TW1-4. Chose this one as it requires a crazily small enclosure (per JL Audio). Paid a lil over 200
https://www.sonicelectronix.com/item...o-12TW1-4.html

Enclosure: Q-Power has an enclosure that is 100% internal volume required per JL. They only sell these in pairs. Bought a pair for 50 from ebay, sold one on craigslist for 50. Not bad. The enclosure has cool external fininshing - bed liner type.
https://www.ebay.com/itm/Q-Power-QBo...-/351244941640

Amp: I like the modern D-Class sub amps - plenty of power in a small box and dirt cheap. I need around 250-300W RMS, liked the specs of this small guy. Was still a bit hesitant.. 1.4 x 3 x 6.5 inches are not the dimensions we expect from a subwoofer amplifier. Still bought it to try. Was just 74 bucks on ebay new. Turned out plenty capable for my sub. I am using the high level inputs of the amp, no external hi-lo converters. Works like a charm. Amp has all the adjustments you need including level, lp filtering, hp filter, and a gradual 45 hz boost if you need it.
https://www.shopmyexchange.com/power...lifier/7384088

Installation

Wiring:
Signal: There is a good thread here explaining in all details how to get signal from the trunk mounted stock woofer amp. I was debating whether to use the signal wires on the left or right side of the connector, decided to use the ones that send signal into the stock amp rather than amplified signal. Turned out just fine, the signal is plenty strong.

Power wire:
I was using the large grommet behind the battery (passenger side) not the one OEM is showing for their system on you-tube. The problem with OEM suggested grommet on the driver side is that it is not easy to run the wire from the battery to the driver side grommet. Passenger side seems a way to go. That being said, i disconnected the grommet itself from the plastic thing it is attached to and it is now virtually impossible to mount it back.. Doable if you are a heart surgeon or gynaecologist, neither of which I am ((( I am contemplating using some sort of permatex sealant (gasket maker) to just glue this thing back in place (actually bought the gasket thing already). You do not need to remove this thing from its place, just check from inside the car (easy to see behind the glove box), where to make a hole, cut a hole and run your wire through. Make sure all your wiring is well protected and secured. (I know two cars that burned down due to substandard car audio related wiring,, one fella competing nationally (IASCA etc) back in europe lol)

Enclosure mounting: I noticed there is a nice nut that is used to keep the spare tire in place. I also noticed the foam insert in the trunk (between the trunk floor and trunk metal), the one that is right next to the rear seat is secured in place by three plastic fasteners. I removed the fasteners and used the holes to install the rivet nuts (metric M8.. just used the cheapo and easy to work with aluminum nuts since i have three of them). The spare tire nut is M8 as well. So i produced a mounting plate (the odd shape mdf piece with 2 million holes.. holes are to reduce weight lol) which is held in place by three threaded rods connected to the front three threaded nuts and one threaded rod screwed into the spare tire nut. Overall turned out secure enough. The thing is kept in place OK, does not shake or move at all. I bought one 1meter long threaded rod which i cut into lenghts i needed. And yes, I had to drill holes in the trunk floor thing (do not do this if you plan selling your car soon)

Enclosure: the above q-bomb box worked fine, except i decided to make the enclosure a tad lower for ease of installation reasons (out trunks are sure small) and added 6-7 liters of internal space from behind. The specs provided by JL suggest their recommended tiny 18 liter net box would result in Fs of 55hz and F-3 of 45Hz.. not bad at all, but resulting Qts of 0.9 is kinda high to my taste, hence added some more space (since i am cutting the top of the box anyways). Here is obviously another mistake of mine.. would be way easier to just build a box from scratch. Spent couple weeks working like 30-50 min a day. Used plastic cote texture paint to get the texture i wanted. (Also tried EX liner and something else which did not look good enough for me). Drying time of plasti-kote paint is like three days lol )) Unexpected but does not smell very bad which is a plus.

Amp is now under the passenger seat, can also be mounted in a bunch of other spaces, like glove box, etc. Have not decided yet.

The whole sub thing took about a month.. two days my ass ((

Pics are below