370z DIY Subwoofer Build

[Matt Pugh]

Hi all, 

 

I recently finished my first ever subwoofer install and I am very happy with the outcome so just wanted to do a quick write up on it! 

 

So like most I had a spare wheel area that was just wasted space and thought it was perfect for a subwoofer, I needed abit more bass and have read mixed reviews over the bose sub that comes with the car so decided to go down the aftermarket route. 

 

My set up is a Juice 1201D Mono amp and a JBL GT4-12 series sub. 

 

I started with cutting out an area for the amp. 

 

 

Then needed to measure how big of an enclosure I needed so made measurements. My first idea was to stack circles ontop of eachother, layer by layer to build up an enclosure but realised this would create a lot of wastage so decided to turn a circle into a 10 sided shape using vectors and a compass etc.

 

 

So I had my measurements and decided to start cutting some 18mm MDF. Started with the top that the sub was going to be attached to and the circle needed sanding abit to make it fit very snug which is what I wanted. Then used that circle as a template for the bottom circle but to my surprise I somehow missed that there is a slight taper towards the bottom so I had so cut and sand abit more to make it fit. 

 

 

I painted the bottom of the sub to see if it was touching the bottom circle which is was so used a router to extract about an 8mm depth around the area of the sub. 

 

Then I started with the 10 sides with a joining angle of 18°. The math I used for the sides was created using the top circle dimensions however as the bottom circle was much smaller it meant the sides weren't going to fit, well 9 out of 10 did but instead of taking some off of each side to make the last one fit, I just made one side smaller as I didn't mind much as you can't see it, I then glued it using tape on the back side which held it together.

 

Then gluing the rest. 

 

 

I simply used the foam enclosure to act as a clamping method then put a weight on the top plate and let it cure. 

Some of the corners do stick out the bottom as it is smaller then the top however this works to my advantage and secures it in the foam enclosure at the bottom. 

 

Next bit was feeding all the wires, i sourced some 4 gauge OFC wire for power and earth and some 14 gauge OFC for speaker wires, to crimp the lugs to the end I used the old vice and a ball bearing trick which worked beautifully. I sourced the wiring harness from r35audio, he was kind enough to sell it to me individually as he has a great sub kit. It plugs into the back of the headunit and runs off 2 RCA's and a Remote cable, the oem harness just plugged into the back of the new harness so it was like a little extension.

 

Here is a summary of feeding through all the wires:

 

 

 

 

 

I routed the wires by following factory harnesses. I cable tied everything to make sure it was tidy and that body panels wouldn't have any obstruction. Every panel only really consisted of clips and one had one 10mm bolt either side but that's it!. 

 

I put everything back in, connected the amp, painted the top of the box and drilled a hole to feed the speaker wires through. 

 

I screwed on the sub and a grill I bought off of amazon for a little protection and all done! Well sortof, I bought a cheap boot mat for £14.99 which I need to cut a whole out of for the speaker and also to buy some plastic for the underlay under the boot mat. I also had to use an angle grinder to chop off the threaded body at the bottom of the boot to make the enclosure fit, along with some foam off the bottom but not all of it. 

 

Finished product and yes it sounds great!

 

 

Also routed a remote for the sub to the drivers side:

 

 

Very happy with how it came out in the end, just a few more finishing touches with the carpet etc and that's it! 

 

If you made it this far, thanks for reading my write up  if you have any questions don't hesitate to ask me either on here or drop me a PM! take care. 

 

Matt

[HEADPHONES]

That is some awesome work there.

With the abuse my puny Bose 10incher has taken over 16 years I'm surprised it's not died yet.

If it does I'd gladly pay for something like that from a pro.

Looks so neat and no compromise on boot space.

[Matt Pugh]

Thank you very much mate, appreciate it! Yeah it's crazy how strong some subs are, they do surprise everyone haha.

 

Honestly I'm a beginner, this was all a first for me so goes to show anyone can do it! But if it ever does go just let me know, I'll be happy to help 👍🏻. 

 

Thats exactly what I wanted, the boot space is small as it is and couldn't afford to lose anymore lol. Thanks 

[HEADPHONES]

I went a bit crazy around 20yrs ago.

I had a 1.3 Nissan Sunny with 3/4 of the boot taken up with a bixed 15" sub.

Just 2 amps.

One running some components up front, no rear speakers.

One bridged running the sub.

Played it WAY too loud and got tinnitus!!!!

I was so devastated I put the sub up for FREE COLLECTION.

Thankfully, 6 months of no sub and the tinnitus went

 

Didn't learn......put a 12" sub in my next car.

Guess what, couldn't resist and started going too loud again.

 

That's why Ive stuck with the OEM 350Z puny Bose

 

[Matt Pugh]

Yeah that is crazy lmao and definitely not surprised you got tinnitus . Honestly don't blame you, probably is for the best haha, safe choice . 

[EvansJD2112]

I dont have your diy skills!
Bought a kit from R35Audio last March

https://www.350z-uk.com/topic/125530-new-sub-with-stock-hu-r35audio-kit/

[Matt Pugh]

Nice one Jon  thanks for your suggestion mate I was able to buy that cable harness which worked perfectly. Had to go down the DIY route because wheels, coilovers and a new exhaust has set me back a little bit