Help with box dimensions?

[Genesis730]

I'm trying to build a side port or slot port (not sure if slot port is possible but I'd like to hear your opinions) box that's appx. 3.15ft³ and tuned to around 32hz. My constraints are H:16" / W: 28" / D: 24" and the box I've come up with is H:14" / W:25" / D:22" (3.194 ft³)

If it helps the subwoofer will be facing upwards. I'm not sure if the port should be on the same face as the sub or if it can be on a sidewall and if so which way it should fire so any info on that would also help!

My question is how do I calculate the port, I've read up on ports but still can't figure out how to make one to avoid port noise and tune to a frequency, ect. so I'm asking for any help or advice. Thanks guys!

[Triticum Agricolam]

We will need some more info. What sub? What vehicle? What power?

You may have to adjust the size of your enclosure some to account for the internal volume the port takes up if you haven't already.

[Joe X]

Here is a suggestion based on infos you provided in earlier threads, power: to sub(s) rated, amp subsonic filter to 28Hz, minimum port clearance 3 1/4", figure is just an assembly guide:

NOTE: If building outside you need to build a cardboard dummy box to test fit in it's way inside.

[Genesis730]

@Triticum Agricolam, the sub I'll be using is the Incriminator Audio Flatlyne 15" 2 Ohm wired @ 4 Ohms, the car is a 2014 Kia Forte LX, and will be powered by a Rockford Fosgate P1000X2 in bridged mode. I haven't adjusted for port volume yet since I'm not sure what would be ideal and that's why I'm here

I forgot to mention in the post that I'd like to use 1" MDF rather than 3/4" to help stiffen the box and prevent flex if possible.

@Joe X, if I'm reading your calculations correctly than the port length will be

19.5" in depth (.75" from baffle + 15.5" from port wall + 3.25" from port itself running back)

+ 16" along the back wall (extension) (15.25" from back port wall + .75" from side port wall)

totaling appx. 35.5" long? and that would result in a port volume of appx. 1 ft³?

Sorry for all the questions, I really appreciate the help I just want to understand what's going and learn rather than just get answers.

[Joe X]

Port has 35.5 center line length as you state and 1.181 cubic feet of displacement including the wood parts. Any questions are welcome.

[Triticum Agricolam]

Instead of using 1" MDF you would be much better off to use regular 3/4" MDF and add some braces. A 3/4" panel with one brace in the middle will be significantly stiffer than the same panel made out of 1" material w/o the brace.

[Genesis730]

Okay, 3/4" MDF with vertical brace.

As for the port, is it best practice to have it on the same face as the subwoofer or can the subwoofer be facing up/down and the port facing out from a side?

[Joe X]

In a trunk car you should avoid subs up, port can be side or same face but same face lets you do a trunk seal off which increase performance in most cases. Adding bracing is always recommended but the baffle being small and sub being low power will not make bracing strictly necessary.

[Genesis730]

Well if I go with the 15" it must be facing upwards. The truck height is 16". 1.5" from box top & bottom + 15.5" sub diameter just won't fit facing forward

[Triticum Agricolam]

Well if I go with the 15" it must be facing upwards. The truck height is 16". 1.5" from box top & bottom + 15.5" sub diameter just won't fit facing forward

JoeX so the box as being 16.5 tall so as long as the cutout diameter is less than 15", which it usually is for 15" subs, it will fit.

Its REALLY to your advantage to mount the sub facing forward if at all possible.