Slot port size question

[hoppins10]

Hello all. This is my first post on this forum although I have been reading posts on here for a while. I have a question about a new sub I got. The sub is a 12" RE MX that I want to build a ported box for. My goal for this system is to have a very strong low end. I am planning on building a box the RE's specs of about 2 cu ft but instead of tuning to the recommended 32 Hz i wanted to go a little lower. I guess my main question is about the port width. I am using this box calculator and want to make sure the port is big enough. I started out with 2" of port width but have been reading elseware of people making the port 4" and higher.

Any input is greatly appreciated

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[akheathen Premium Member]

it's about the sqare inches of the port HxW in relation to the box size, and driver. you can use other calculators to tune your vent, if that one will not allow you to change frequency...

 

[RAM_Designs 5,000+ posts]

I'd do 2.25ft^3 at 28hz and use 30-35in^2 of port.

 

[hoppins10]

I'd do 2.25ft^3 at 28hz and use 30-35in^2 of port.

Thanks Ill plug some numbers and see if it is doable. Hopefully I can get away with a simple L port rather than having to "snake" it

 

[RAM_Designs 5,000+ posts]

It's going to be a long port. Yoy have a high throw woofer and a low tuning...a long port is inevitable, but hopefully it'll be under 40".

 

[hoppins10]

It's going to be a long port. Yoy have a high throw woofer and a low tuning...a long port is inevitable, but hopefully it'll be under 40".

Do you have any suggestions to a better box calculator than the one I have been using on RE's website

 

[brandinooooo 10+ year member]

Thanks Ill plug some numbers and see if it is doable. Hopefully I can get away with a simple L port rather than having to "snake" it

If you can, try to make it wider rather than box-like if that makes sence. If you have problems fitting it you can always reduce the width of the port to shorten it a bit.

The RE enclosure calculater is the easiest I've seen to use.

 

[RAM_Designs 5,000+ posts]

Do you have any suggestions to a better box calculator than the one I have been using on RE's website

I use the calculators at carstereo.com, under the "how to" tab. The RE calc is simpler and easier, but because of that doesn't take into consideration some things that I do, so I use individual calcs for box volume, object(port/bracing) volume, and port length, and plug-n-chug until I make everything mesh well...doesn't take too long after you get used to it, and you get precise results instead of generic empty-box stats like with the RE calc.

 

[Cruzer 10+ year member]

supposedly re calculator is off, and when i do other peoples calculations, like jl from their site, or ssa from their site, etc. it doesnt show up the same on the re calculator.

so even if u do use the re calculator and get it all perfect to 2cubes @28hz, it will probably be like 1.8 cubes @ 32hz or something.

that is if its true that its not accurate

 

[surreal 10+ year member]

Ram is about right. Being theres a good bit of xmax though not a whole lot, and the low tuning you should be fine at around 30-32square inches of port regardless of box size. Some rounding and all will help. No reason to go bigger than needed as youll essentially only be wasting space.

Ah.. I see Ram checks all of this already as he has said. Good guy.

The RE calc just doesnt take into account displacements. Thats the biggest thing. Otherwise its a wonderful little tool and can simplify design for many people.

 

[iLL Ridge 10+ year member]

Yep I think the re calc is great and accurate and simple, minus the bracing and sub displacements. But hey I'm still new so...