Build box bigger than sub specs?

[Murphyokc]

First post here. I am wanting to build a box with a round flared port since it is simpler to build and I can’t find any boxes online that will fit the way I want because it is going on a boat under the drivers dash area.  I’m gonna upgrade my stereo and put a Skar evl 12 in.i will probably eventually add a second one to the passenger side.  Specs show ported box is 2cf and port area is 24in square I believe. My problem I’m having is if I make the box 2cf then the port would be longer or almost as long as the box would be. Also if I do a round port I can’t find one that matches the 24sq in. So I have a few questions. Should I get a smaller port 5”  and make it around 19sq in or get one that’s  6 in and make it around 28sq in? Also would it affect the sound if the port was facing the front and the sub was facing towards the side or should they both face the same direction?  I was going to tune it to about 36hz. If I make the box longer I should be able to fit a 6 inch port but I wasn’t sure how much past 2cubic ft I could go and still not risk anything. Has anyone made it where their port sticks out past the box to where it doesn’t look goofy? Keep in mind this is in a boat so it’s a open environment unlike in a vehicle. Sorry for all the questions. I’ve never built a ported box and I wanna get it right the first time 

[Dafaseles]

I've read that you can really go up to 25% bigger with sub boxes than factory specs, and that a lot of people actually prefer bigger. Just make sure that if you go, let's say 15% bigger, then the port should be 15% bigger too. Also, if the port ends up longer than the box, you can always make an "L" in there back of the box. Just make sure the square footage of the box doesn't include the displacement of the port inside the box, and rounded or angled corners are better for air flow than sharp, 90 degree corners. Now, as far as being an open air setup, I don't know how that effects things. Making the box a little bigger does improve output, but makes the sub a little less efficient, and I'm worried about being an open air setup, the efficiency might already be effecting the sub a little. Not saying don't do a ported box, I'm sure people do it all the time with a ton of success, but if I had a boat, if the sub wasn't in a cabinet of some sort, I'd do a sealed enclosure or a 4th order bandpass. A lot of people talk about if you do sub forward, you do a port to the side. Hope that helps a little

[1point21gigawatts]

1 hour ago, Murphyokc said:

First post here. I am wanting to build a box with a round flared port since it is simpler to build and I can’t find any boxes online that will fit the way I want because it is going on a boat under the drivers dash area.  I’m gonna upgrade my stereo and put a Skar evl 12 in.i will probably eventually add a second one to the passenger side.  Specs show ported box is 2cf and port area is 24in square I believe. My problem I’m having is if I make the box 2cf then the port would be longer or almost as long as the box would be. Also if I do a round port I can’t find one that matches the 24sq in. So I have a few questions. Should I get a smaller port 5”  and make it around 19sq in or get one that’s  6 in and make it around 28sq in? Also would it affect the sound if the port was facing the front and the sub was facing towards the side or should they both face the same direction?  I was going to tune it to about 36hz. If I make the box longer I should be able to fit a 6 inch port but I wasn’t sure how much past 2cubic ft I could go and still not risk anything. Has anyone made it where their port sticks out past the box to where it doesn’t look goofy? Keep in mind this is in a boat so it’s a open environment unlike in a vehicle. Sorry for all the questions. I’ve never built a ported box and I wanna get it right the first time 

Please look for different option than Skar audio. The reason it’s so appealing is because it’s cheaply priced for what they say it can do and handle for a long period. When it really only handles and does for a short period. But remember, if something is cheaply priced then that means it was made for cheap. Thus cheaply made. Dude on here the other day just got a Skar zvx 18” subwoofer and on the second day the seams on the subwoofer came unglued. Don’t let the cheapest and most appealing option catch you. 

[Murphyokc]

I’m not choosing it because of the price, I’m choosing it because of the many good reviews I seen.