Deciding to port box or upgrade sub

Jason Clark · Jul 27, 2025

I built a custom 1 cu ft box, box is well built 3/4 mdf, glued screwed etc. It fits under the rear seat of my 2022 Silverado crew cab, which is why I went the custom route (most of the bought boxes are .5). I picked up a p3sd4-10 for it at a great deal and it's paired with an alpine S2-A60M. I've tried empty box and tried stuffing some polyfil in, but can't seem to get the sound I'm after. I find the bass almost too sharp, and more of a dull thud than what I'm used to. The amp and sub aren't quite a match, given 600W output at 2ohm for a sub rated at 300. I keep the gain at half or so and cross over just under 80hz.

It's a sealed box currently, and I'm contemplating either porting the box or potentially changing the sub. Any advice would be appreciated, from what I've been reading the box is going to have a bigger impact than changing the sub. The sub I was thinking of was the JL Audio 10TW3-D4

Thanks

huberoy123 · Jul 27, 2025

I ported my box, but it became clear that I also needed to upgrade my sub. Just my personal experience.

1aespinoza · Jul 27, 2025

Jason Clark said:
It's a sealed box currently, and I'm contemplating either porting the box or potentially changing the sub. Any advice would be appreciated, from what I've been reading the box is going to have a bigger impact than changing the sub. The sub I was thinking of was the JL Audio 10TW3-D4

Shallow subs are not too bassy. Only ones I have heard about that really perform are the pricey ones like JL's TW3, TW5, Fosgate's T1s, and Stereo Integrity's BM11.
If you have the depth, you can try Sundown's SA10 Classic. It needs 0.75cu.ft. Anything bigger than that will negatively affect performance IMO.

Mitchell Fosgate III · Jul 28, 2025

Just leave it on the seat so you can make it better. Or bigger. The bigger the better.

shredder1 · Jul 28, 2025

1ft3 net box, so like .96 with a shallow. Probably.
If you dare to port it I'd make sure the port is completely external. Try a 3" round tuned where you want it for your goals. 14-15" long with a 3" should put you in the neighborhood of 35hz. Just be sure to keep it totally external.
Sealed in a truck usually peaks 45-55hz really hard as the cabin size adds gain at those frequencies, hence a system that "knocks" instead of what most seek... Extension with strong beats.

Jason Clark · Jul 28, 2025

So I ended up picking up a JL TW3 for cheap and put it in my other sealed box I had laying around. There is no comparison between the P3S and the JL, problem solved!

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Deciding to port box or upgrade sub

Jason Clark

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huberoy123
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1aespinoza
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Mitchell Fosgate III

I recommend just do it.

shredder1
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Jason Clark

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Deciding to port box or upgrade sub

Jason Clark

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huberoy123 10+ year member

Member

1aespinoza 10+ year member

Junior Member

Mitchell Fosgate III

I recommend just do it.

shredder1 10+ year member

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Jason Clark

CarAudio.com Newbie

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Jason Clark

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1aespinoza

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huberoy123
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1aespinoza
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