FYI: B/O Sub Box Volume and Stereo Build

icanski2

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I am in the middle of a huge audio build in my 2020 Max Platinum. There isn't a lot of info out there on the subject so am taking a lot of pics I plan on doing a build thread to show some of details after I get finished. There is a lot if bad info on the factory sub enclosure floating around so I did some fairly precise measuring using water and have determined the enclosure space is .7436 cu ft. The sub I am using for this enclosure is a Sundown Audio SD-4 10 D4. It requires making the opening a little bigger but its a great match to this box. The factory enclosure is actually pretty well built. It was molded with a lot of structural support on the inside to minimize flexing so it should work pretty good after applying some deadening to it.

The equipment I am installing is:
Front Speakers - JBL 670GTi components (Focal Utopia M 3 way set is in the near future but damn $$$$)
Front Amp - JL Audio VX600/6i for front 4 channels bridged for the mids. The remaining two channels for tweeters. Running speakers actively crossed. (200 watts x 2 @ 4 ohms & 75 watts x 2 at 4 Ohms)
Rear door Speakers - JBL 670GTi components
Rear door Amp - JL Audio VX600/6i for front 4 channels bridged for the mids the remaining two channels for tweeters. Running speakers actively crossed. (200 watts x 2 @ 4 ohms & 75 watts x 2 at 4 Ohms)
Factory Sub Enclosure Amp - JL Audio VX600/1i running a Sundown Audio SD-4 10 D4. (600 watts RMS @ 2 Ohm)
Front Center Channel 3.5 inch Infinity Reference 2 way powered by a SounDigital 400.4D EVO Amp
Rear D pillars 2 3/4" Kicker mids for rear fill powered by the same SounDigital 400.4D EVO Amp
Main Sub - JL Audio 13W7AE D1.5 in a sealed enclosure. I will make this box removable if the space is needed. The sub alone weighs 52 lbs without box. It is a beast!
Main Sub Amp - JL Audio HD1200/1 (1200 watts RMS @ 3 Ohms)

Everything will be thoroughly sound deadened and will be tuned using the JL DSPs in the amps.

To be continued.............

sub box.jpegrear.jpeg
door3.jpeg
door4.jpeg
door2.jpeg
 
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Jerald Cook

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Very nice and I look forward to the build thread. While I'm overall very happy with my decision to buy an XLT over a Limited/Platinum, the 6 speaker stereo in the XLT is really, really aweful. Hopefully following your build thread will give me some insight and inspiration for my eventual stereo upgrade.
 

KARWECK

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Looks great! I'm in the design phase with my build. I'll be sure to follow this. Have you checked out Sounds Good Audio? They offer custom front pillars that allow you to add 3.5 speakers along with the tweeters. Little pricey, but I'm considering it. Also, I've heard you can add some acoustic insulation to the inside sub box and have it perform as if the volume was 1.1 cf.
 

Jerald Cook

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Sounds Good Stereo also has a decent Youtube channel and they did a series recently upgrading a Gen 4 Expedition. They even have some custom parts in their online store to help with install conversions.

 
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icanski2

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Looks great! I'm in the design phase with my build. I'll be sure to follow this. Have you checked out Sounds Good Audio? They offer custom front pillars that allow you to add 3.5 speakers along with the tweeters. Little pricey, but I'm considering it. Also, I've heard you can add some acoustic insulation to the inside sub box and have it perform as if the volume was 1.1 cf.
You can add it if needed but the airspace specs for my sub are .5 to .75 cf so it wasn't needed. I have actually added some spray foam to the inside to get it closer to the .5 side of the spec. smaller box is better for the way I am planning on tuning the two subs, plus it helps control driver excursion because there isn't much room between the sub and the trim panel grill. Sealed enclosures that are too big can cause problems controlling the driver excursion (Xmax) and reduce the power handling ability of the sub. A driver with a large Xmax will require a custom grill fabrication to prevent contact between the woofer and the grill in our Expeditions.
 
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icanski2

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Sounds Good Stereo also has a decent Youtube channel and they did a series recently upgrading a Gen 4 Expedition. They even have some custom parts in their online store to help with install conversions.

Yes, I saw those videos when they first came out. They do some really nice work there. I did buy the door block off panels I;m using from them. They are vey well made and fit perfectly.
 
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