Diy Center Console Subwoofer Install - Double Cab

[Ripper]

Hi guys. Hooked up a subwoofer to my truck over the holidays and thought I’d share my experience with you guys. Hopefully it will be of some help to somebody who is planning on doing something similar.

Its a fun DIY but if you're on a budget, best is to get it done by an audio shop. I wanted to do it cos i lke DIY despite the time and financial costs

The patient

When I moved to a double cab from a car, the single biggest trade off was not having good acoustics. I had a decent audio system in the car and except for the headunit I couldn’t transfer anything to the truck due to sizes not matching. I ran clarion competitions series 3 ways in front and alpine type R 6x9’s at the back with tweets on the A pillar. All powered directly off a pioneer 6950ib.

I didn’t like the sony headunit that came with the truck so managed to swap that to the one I had in the car before I put it up for sale.

The “new” headunit made gynonamous difference to audio quality even with the rest of the system being the same. But bass response was almost non-existent. The truck has 4 speakers in all four doors with fronts with 6” 2-way pioneer’s and rears being 6” 2-way JVC’s. The door thickness doesn’t allow me to put better speakers cos almost al good speakers have large magnets and are deep. The only way to get some decent bass out of the system was to hook up a dedicated subwoofer.

And this is where the problems begin. Unlike with a car, double cabs have very little space for a sub. And subs generally tend to take more space. Even smaller ones. The only space I could possibly fit a sub was either behind the back bench seat or underneath the front two seats. I took the front seats out, measured the distances and thought I could fit a sub there. So went ahead and got two JBL GTO 8” subs and a JBL amplifier. Also a BULLZ audio amplifier wiring kit off ebay.

wiring kit

space under the seats

under-seat enclosures that didn't workout

Just to get into a bit of detail about powering a sub. There are generally two types of subs. “Active subs” and powered subs that have an amplifier built into it and doesn’t require a separate amp to run them and are fitted into an enclosure from the factory itself. “Passive subs” on the other hand needs an enclosure to be built and also an amp to power it. Passive subs offer more performance and can be customized to suit a particular vehicle or your needs. I opted for this option cos there was no space to decent active sub to fit into my truck.

[Ripper]

Power wiring

Depending on power output, an amplifier needs a pretty decent supply of current from your electrical system. You need to run a heavy duty + power wire straight off the battery to your amp. The negative terminal of the amp can be grounded to the body itself using a heavy gauge power wire. I used 4gauge power wire.

Most headunits have a switching power wire that supplies a bit of current once the headunit comes on. You need to connect this output from the headunit to your amplifier so that the amp will come on only when the headunit is on. It’s a low power circuit so you can use a normal 12v power wire for this.

You need to have a fuse on your main power line as close to the battery as possible. Within 18inches from the battery terminal is general rule of thumb.

Buying an amp wiring kit really comes in handy here cos all the power wires, speaker wires, crimps, fuses etc are all part of this kit. I bought a Bullz audio wiring kit off ebay. Not the best quality stuff, but for my purpose it was good enough. I did use speaker wires that I bought from SL cos the ones in the wiring kit wasn’t good enough.

The fuse on the main power wire

chanelling the power wire through the firewall and under the floor carpeting

[Ripper]

Audio wiring – headunit to amp

Most headunits these days have a direct sub drive. You just need to wire this output to the input of your sub amplifier. Cables are included in the sub wiring kit. Easy stuff

Audio wiring – amp to speakers

Amps come in different specs and types. “full range” amps can run full range speakers, meaning that they can reproduce both high frequencies and low frequencies.

“Monoblock” amps are specialized sub amps and they run low frequencies. Ideally to run a sub, you should use a monoblock amp. But in my case, I got a full range amp that has the option to be run as sub amp. So if i do upgrade later to a monoblock amp, i can use this amp to run door speakers.

Amps have a power rating compared to a particular impedance. Say you have an amp that's advertised as 1000w. It will only give out 1000 of power at a certain speaker impedance. Usually that spec is in the finer print If the amp was designed to give out 1000w at 2ohms and you end up connecting speakers that are 4ohms, the power delivery will be a lot less than the rated 1000w.

Simply you gotta read all instructions, detail about an amp before wiring it up with speakers. In my case the amp was a 2ch one. And it's gives out it's max performance in bridged mode. Amp bridging is simply combining the 2 channels into single channel. Not all amps allow you to bridge them. Bridging usually lowers the impedance and increase max output. Say a 4ohm 2ch amp with be 2ohm, 1ch after bridging. It will be using more electrical power and will be generating more heat this way. And this is why you should never bridge an amp that was never designed to be bridged.

You can visit www.crutchfield.com for amp wiring diagrams to see how impedance can be matched how you can wire 1 or more speakers to an amp. They have nifty little diagrams for different setups.

Once you figure out your setup, connecting wires from the speaker to the amp is dead easy. make sure to use proper connectors, crimps etc from the wiring kit.

Amplifier mounted behind the back bench seat.

Enclosures

This was the trickiest bit for me due to space restrictions.

Just to detail a bit about enclosures. There are three types of them.

1.Sealed enclosures

As the name suggests, these sub boxes are fully sealed with zero air leaks. They take the least amount of space, easiest to get right but needs the highest power from the amp to be driven to it's max.

2. Ported enclosures

These seem to be the most popular in SL for some reason. They have one or more "ports" open to the outside. When the sub is pumping, you will get an airflow out of this port. They take more space than sealed boxes and are more difficult to perfect. But in terms of power delivery, they are superior to sealed boxes.

3.Bandpass enclosures.

Very rare these days cos they take more space and are a lot harder to be perfected. They offer best audio quality and best power delivery.

Hardware

2nos JBL GTO 8" subs

JBL GTO 2ch full range amp

Bullz audio wiring kit, 4gauge

1/2" thick plywood

Silicon caulk and caulking gun

Jig saw, circular saw, drill, hole saw to the size of your terminal cups

straight edge or long steel ruler, builders square and or set squares.

screw drivers, hammer, woodworking screws, nails, wood glue

Polyfill

carpeting material of choice to cover the enclosure, box cutter to cut the material

glue, i used "grip" brand

Sandpaper, file,

Soldering iron, soldering lead wire

Terminal Cup

[Ripper]

Enclosure build

Since space is a huge issue for me i had no choice but to go for a sealed box.

Each subwoofer requires you to have a certain volume of air inside the enclosure to work properly. The documentation that comes with the subwoofer generally includes all these specs. These numbers are different for different types of enclosures. The subs i got needed 0.3cubicft of air minimal in a sealed enclosure configuration. Depending on space availability, you can do the math an figure out the box dimensions. I'm guessing that most of these audio shops don't really custom make these enclosures for obvious reasons. So building your won enclosure means has this huge advantage of having the perfect box as it was intended by the sub manufacturer.

I made a mistake in my first two sealed boxes. After finishing both the boxes, i realized my measurements were off and i couldn't get them to fit under the front seats. Even with spacers to lift the seats a bit. Since the seats need to be able to slide back and forth and the cable mechanism under the seat too is eating out space, i had to throw away the under-seat sub idea

Test firing the under-seat sub ensloure.

The only other place to fit my sub was between the front two seats, where you'd get a center console in other vehicles. So the new plan was to use only one 8" sub and somehow make an enclosure to fit it as a center console.

This time i thought of making a dummy box with corrugated board first and test it for size before taking the saw to plywood.

cardboard replica

I had some formal training in architecture and that came in handy. Set squares etc were all there at home so managed to quickly draw things up on board. After all pieces were drawn and cut, a bit of tape is all it took to make the panels into a box.

It fitted perfectly to the space i have between the seats so i used those panels as templates to cut the wood. You gotta keep an allowance for the thickness of wood when you make the patterns on wood. Measure thrice, cut once

[Ripper]

I prefer the use the circular saw to cut log straight lines and jog saw to do finer bits. Circular saw take some getting used to but it cuts wood really fast. Jig saw is slower and you gotta be good at it to make true straight cuts.

I bought 1/2inch thick 4'by8' sheet of plywood from a hardware shop. Dont need so much of wood but they don't sel cut pieces. And i can always do something else with the other bits of wood. If your running a bigger sub in a larger box, you might have to buy 3/4 or 1inch thick plywood.

"saw horses" to rest the plywood on when cutting

Once all the panels are marked out, i cut out all the pieces with the circular saw. The opening for the sub to fit in should ideally be cut off with a jig saw before seperating that panel from the main sheet of wood. You can use a hole saw to cut out an opening to fit the terminal cup the same way.

test fitting the sub

Use sandpaper to smoothen out edges if required. I ran a bead of wood glue on all edges before fitting them together. It's easier to drive a few nails first to hold the panels in place and then to use screws to ensure a proper fit.

the little red colour brush next to the paintbrush is my 3 yo son's input for the project he was pitching in to clear out saw dust

Edited April 16, 2012 by Ripper

[Ripper]

When you come to install the last panel, cut open that new tube of silicon caulk and run thick beads of caulk on all inner seams. You can smoothen the edges with a finger before it dries out. After this you can install the last panel and use the subwoofer opening to caulk the edges of this panel. Once its done, all inner edges should be siliconed properly so that there are no airleaks.

Leave the finished box in the sun to dry the silicon out. The caulk i used gives out acidic fumes while it's drying and if you were to install a subwoofer into it, those fumes can corrode the sub motors etc.

Once the caulk is cured properly and you can't smell any fumes, you can start carpeting the exterior. Visited an upholstery shop closeby and bought some great color carpeting material to match my interior.

You can cut the material with a box cutter and a straight edge like a steel ruler and then glue it to the wood panels. I made a little sleeve on the front end of the box to hold a charging phone or the ipod. My headunit has ipod compatibility and with a cable all the playlists etc can be browsed via the headunit. Standard on most mid to high-end pioneer units.

After cutting open the carpet material, you can install the terminal cup and the subwoofer. I soldered a speaker wire to the terminal cup and crimped on spade connectors to the other end.

Fill the enclosure with poly fill before installing the subwoofer. I bought a polyfill cushion from arpico cos i couldn't find polyfill for sale seperately. The cushion cost 500 bucks or something. Once that's done connect the wired leads and screw the subwoofer and terminal cup into place.

If you have a sub grill, now is the time to install it. I dont have one so enclosure construction bit is done.

I will be using a steel bracket that screws into the bottom of the box and then to the bolts that hold the seats down to the body.

Connect the speaker wire from the amp to the terminal connector on the sub and you're done!

finished enclosure

[Ripper]

Adjusting input gain on the amp

If all wiring bits are done properly, now your sub should be powering up when you power up your stereo. Like a new engine, subs too need to be "broken in" so be gentle the first few days.

To adjust the input gain on the amp...play a dynamic track, say at 75% volume and turn the input gain up until you can hear distortion from the sub.

Then slowly turn it down until the distortion goes away. There is a sweetspot where the distortion is not present but you still have enough power output.

Do not play tracks in high volume if distortion is present. It can kill your speakers due to an effect called "clipping". In a nutshell, power signals to speakers go in sine wave pattern and this makes the excursion on the diaphram smoother. Distortion clipping is when you over power an amp to the point where the sign wave looses it's smoothness and become a squarish wave. And unevenness of this waves i what kills speaker motors.

So folks, that's one way to install a subwoofer to your vehicle at home. things are a lot easy if you're not limited by space as i was.

Disclaimer:

I'm not an audio specialist nor a woodworking specialist. Just like to listen to good music and enjoy DIY projects over weekends. I've done a lot of reading before taking this project on. Easily over 6 months of research. There might be technical in-accuracies and this is in no way the best way to do a sub project. It just fitted my needs and works great.

[terrabytetango]

Care to share plans? I believe I can use that as a dicky sub enclosure without getting in the way of my planes when I'm moving them. And how have you handled noise suppression? And not to knock your truck, but what about the bass resonance that is natural to diesels? Does that interfere with the sound output (i.e. self cancellation at certain frequencies)?

[VVTi]

Ado, kick ass!!!!

[kelum_wj]

Awesome Btw you could have padded the top of the enclosure as could be used as an armrest in long drives

Edited April 16, 2012 by kelum_wj

[trinity]

Wow thats super cool machan...... great job...

[tiv]

Nice one mate,

[Ripper]

  On 4/16/2012 at 10:39 AM, terrabytetango said:

Care to share plans? I believe I can use that as a dicky sub enclosure without getting in the way of my planes when I'm moving them. And how have you handled noise suppression? And not to knock your truck, but what about the bass resonance that is natural to diesels? Does that interfere with the sound output (i.e. self cancellation at certain frequencies)?

well machang there weren't really plans as such. I had to have 0.3cubic ft or more volume inside the box. The box had to fit between the two seats, couldn't be taller than a certain height cos that way it would interfere with shifting. The only thing i had some flexibility over was with the length of the box. within all those constraints, i rigged up the box.

Also the internal air volume is different from sub to sub. The one i used is a shallow mount sub that needs minimal air volume. You might want to put a bigger sub than an 8". If i had the choice i would have done the same.

If you want, i can just draw up how i fitted the panels.

When you say noise suppression, if it's sound dampening within the box...i've used Polyfill. Right behind the subwoofer vent, i've used the supplied rubber matt thing too. But generally from what i've read, polyfill is good enough.

As for the diesel thing. It really boils down to the amount of soundproofing a vehicle has. The Ford is prety good in this when compared to say a similar vintage Hilux. If i could add some soundproofing to the doors, , bonnet, firewall and rear panelling...i can knock down a lot more interference from outside.

Having said that...i dont really any engine sounds etc when i have the audio running. No cancellation or anything of that sort.

AFAIK..For the noise cancellation thing to happen, wave lengths should match and i should be in opposing directions. A very rare event imho!

  On 4/16/2012 at 10:46 AM, VVTi said:

Ado, kick ass!!!!

Thanks Machang!

  On 4/16/2012 at 11:00 AM, kelum_wj said:

Awesome Btw you could have padded the top of the enclosure as could be used as an armrest in long drives

Thanks. The carpeting material i used is a good 3-4mm thick machang and it has a rubber/foam kinda backing. So it doesn't feel hard when you rest your arm on it.

did a few drives after hooking this up and it wasn't bad. Dunno if it will be different on long drives.

I measured the height and fixed it to the best possible place for me to rest my arm on it

  On 4/16/2012 at 11:34 AM, trinity said:

Wow thats super cool machan...... great job...

thanks machang

[bogzy]

Great Job & some nice explanations.

Thanks Ripper.

[NPP]

Awesome finish Ripper. Looks like factory fitted!

[Kavvz]

Nice post 'Ripper"

[Shehan_WCC]

Great stuff ripper. You can make a business out of it ....

[nexus]

awesome work Ripper and fine craftsmanship congratulations.

[MeanGreenZ28]

awesome work Ripper! Gonna put a grille to protect the cone?

[Ripper]

Thanks guys!

[Ripper]

  On 4/17/2012 at 4:38 AM, MeanGreenZ28 said:

awesome work Ripper! Gonna put a grille to protect the cone?

yeah machang! need to get one shipped down cos you cant get decent ones here.

ebay have em but shipping rates are a lil high.

[terrabytetango]

What I meant by "noise suppression" was electrical noise suppression i.e. humming and other interference from the vehicle's electrics.

[harshansenadhir]

Great weekend project and really nice work and explanations given.

I'm sure you will re-do this again with probably more improvements such as an additional mapbox/glove box as additional storage and a better cusionned arm rests for driver and the front passenger . Improvement cycles are hard to avoid when you're a die hard DIY fan

[Ripper]

  On 4/17/2012 at 4:58 AM, terrabytetango said:

What I meant by "noise suppression" was electrical noise suppression i.e. humming and other interference from the vehicle's electrics.

Not a massive audiophile but i can't seem to pick up any clutter in that sense. Maybe because all the groundings etc are in good shape and i haven't mucked around badly with wiring bits.

  On 4/17/2012 at 5:56 AM, harshansenadhir said:

Great weekend project and really nice work and explanations given.

I'm sure you will re-do this again with probably more improvements such as an additional mapbox/glove box as additional storage and a better cusionned arm rests for driver and the front passenger . Improvement cycles are hard to avoid when you're a die hard DIY fan

heh heh... unfortunately you're right machang!

i want to setup some mid range speakers on the A pillars cos right now audio is channeled from side and the back and not really from the front.

[harshansenadhir]

  On 4/17/2012 at 6:15 AM, Ripper said:

heh heh... unfortunately you're right machang!

i want to setup some mid range speakers on the A pillars cos right now audio is channeled from side and the back and not really from the front.

how about set of quality tweeters fixed to the each corners of the dashboard where it meets A pillars?