My sub/system build...any feedback?

I first would like to thank those that have been so helpful in this forum with feedback and advice (shout out to Marv).

Background:
My taco came with the JBL sound system with a Kenwood DNX-5120 HU. While the HU wouldn't have been my first choice, it was already in my truck when I bought it - it was a dealer upgrade.

The stereo sounded decent, but I've been a little spoiled with my last few vehicles that had Bose factory sound systems. So the more I drove the truck the more I wanted to upgrade the system.

My key objective was to maintain the factory look (including the back wall surrounds and the covers on the back of the seats).

So, I decided to upgrade the factory JBL 8" sub with a JL 8" sub, utilizing the same OEM plastic enclosure I replaced the sub. As soon as I turned the system on, it was evident the factory JBL amp wasn't sufficent to power the new sub. So I dug through my storage and found my old skool Soundstream Little Wonder and decided to hook it up.

It did sound better, but the bass was disappointing. I wasn't looking for loud bass, just enough sound to fill out the music. So I turned to this forum and started reading around.

The first thing I realized is there are pre-fab solutions available out there (Super Crew, Taco Tunes, etc.), however these pre-fab solutions require you to either modify/remove panels or remove the child restraint tethers.

Then I was going through Marv's pictures and discovered a little shorty box he had made and it got me thinking - what if I could purchase a shallow mount 10" sub and create a box that would go behind the OEM JBL back wall panel.

So I dusted off my table saw and got to work. The attached is what I came up with.

The box dimensions are 24" (w) x 11" (h) x 4" (d) or roughly .61 cub ft with a notch cut out of the top for it to fit under the brace across the back wall. I'm using a Pioneer Premier 10" Shallow Mount Sub (recommended dimensions .35 - .75).
Should my box do the trick?

How much Polyfill should I use?

Next, I'm going to rerun speaker wire to all the door speakers from the HU (since I'm sure the aftermarket HU has a higher output than the JBL amp). Anyone have a better idea? Is there away of taping into the JBL harness behind the radio to get to the speaker wires or do you have to use the JBL amp?

Then, I will put it back together and see how everything sounds.

I'm looking for any feedback from those that have done this so far.

Thanks!

 

I'm choosing to run new speaker wire from the doors back to the rear of the cab where I will have a 4ch amp. The factory wiring will be tucked away. This way, I don't have to deal with the dash anymore than necessary and I can put everything back to normal for whatever reason.

Not sure if a 4ch amp was in your plans, but that's my advice for the day.

 

Looking good so far however "Houston we have a problem"! Your airspace is not actually .61ft^3 since it appears you used the outer dimensions to arrive at that number without accounting for the notch. By my calculations you have less than .3ft^3 and I don't think any amount of polyfill is going to help.

 

Thanks for the feedback. I just noticed I misquoted the depth it is actually 5". Ooops!

I get 0.43294 (not taking into account for the notch). I will have to go home and measure that to make sure I'm ok.

Marv I have a question for you...

When you buy component speakers like the ID 6.5's and they have a crossover. Does the crossover have both a high pass for the tweeter and the 6.5" OR is it just for the tweeter?

The reason why I ask, is my HU has a HPF and I'm wondering if it is redundant with the crossover that comes with the speakers?

Thanks!

 

MUCH better on the airspace! The passive crossover is used between the mid/tweeter of a component set (high passes tweeter/low passes mid in most cases however some just roll off the top naturally) but it does not high pass the bottom end of the mid so you will need to use the headunit or amp crossover for that.

 

Yeah!

Perfect - thank you!