Help pls. Box build for 2018 WRX trunk. 2-12s sundown

[James671Guam]

I've got 2 - 12"s 750w dual 4ohm sa series subs freshly ordered. On its way in and been stressing pretty hard on box dimension.. Originally planned on keeping it simple and going with a sealed box but tons of reviews keep pushing toward ported sooo.. With that said, I really need some disparate help box design please.

my max width in a 2018 wrx is (width30")--(ht 15")--(depth 25").

so I'm praying it can be done with in this field. Any feed back will more than greatly be appreciated. 

Thanks again all the way from guam.

 

 

[Kocyandia]

Any idea on what you're wanting to tune to? What size amp? I spec'd out a ported box for a single a week ago. I dont remember the dimensions though. It should be able to be done but may be close. Real quick run out in the images. Im sure its not right but its my shot. I couldn't tell you how to begin to use sketchup so I cant help ya there. Close to sundowns reccomendations. But 32hz tuning. Anyone here wanna look that over?

[James671Guam]

(Amp)SFB-1500D-Sundown-Monoblock-1750w

responding and your efforts. Is much appreciated. 

I will do my best to build according this feed.

I will follow up in a week or 2 let you know how it goes.

much respect thank you so much (((🔊)))

[Kocyandia]

The port length you see that is 33" is how long the center line of the port needs to be. On the side where it says physical port length is how long the actual port wall on the inside of the port needs to be. Not the part that is the sides of the box. But the actual peices you cut for your port. Dont forget the thickness of your baffle counts as port length as well for the centerline length which is the 33"

[1point21gigawatts]

29 minutes ago, Kocyandia said:

The port length you see that is 33" is how long the center line of the port needs to be. On the side where it says physical port length is how long the actual port wall on the inside of the port needs to be. Not the part that is the sides of the box. But the actual peices you cut for your port. Dont forget the thickness of your baffle counts as port length as well for the centerline length which is the 33"

Incorrect

[1point21gigawatts]

19 hours ago, Kocyandia said:

Any idea on what you're wanting to tune to? What size amp? I spec'd out a ported box for a single a week ago. I dont remember the dimensions though. It should be able to be done but may be close. Real quick run out in the images. Im sure its not right but its my shot. I couldn't tell you how to begin to use sketchup so I cant help ya there. Close to sundowns reccomendations. But 32hz tuning. Anyone here wanna look that over?

That’s not a bad design. It needs more net volume, but other than that, it’s nice. Kudos. 

[Kocyandia]

3 minutes ago, 1point21gigawatts said:

Incorrect

Fill me in homie.  That's how I've taken it.  Any info is appreciated.

[1point21gigawatts]

Physical port length is the length down the center of the port. That 33” is effective port length which is what the subwoofer actual sees. So to figure the physical length or vise versa, you have to factor in the correction factor, which is half the width, or height if it’s a horizontal port, which is 2” in this case, negate that from the 33” effective length and that equals 31” physical port length. That is a long port, so it will make a bend and to find the actual center measurement, you have to factor in that 2” correction factor twice on the bend since it turns a corner in the middle. The port walls will be smaller than 31 total inches, since there is a bend. 

[Kocyandia]

19 minutes ago, 1point21gigawatts said:

Physical port length is the length down the center of the port. That 33” is effective port length which is what the subwoofer actual sees. So to figure the physical length or vise versa, you have to factor in the correction factor, which is half the width, or height of it’s a horizontal port, which is 2” in this case, negate that from the 33” effective length and that equals 31” physical port length. That is a long port, so it will make a bend and to find the actual center measurement, you have to factor in that 2” correction factor twice on the bend since in turns a corner in the middle. The port walls will be smaller than 31 total inches, since there is a bend. 

I was goin off a post I had seen on here before from Joe X as to what physical length was. And the explanation Torres gave for each paramater. Thats what I've been doing this whole time lol. May explain why my current box plays so low.

[1point21gigawatts]

This would be what that port design would be if the port was on the front of the enclosure, not center port, sub back port back, double baffle.