alpine swr12d4 aero port sub box help

[rogerz]

im currently trying to design and build a sub box with a custom aero port for my 12" type R. i have done lots of reseaching and overwhelmed with info. so here is my question. i have a box designed that has a gross volume of 2 ft^3 with one 4 inch aero 16-18" long. considering the (9-12 in^2) rule my box is a little off. but what will happen? psp port caluculator says i should have a 15-16 4" port with that size box for around 30-35hrz. (which is my goal)

i will have roughly 5.5" flared ends on my aero ports

Will my box design work?

i am not looking for tunning perfection, but just want to do it right and not waste my time building a POS box.

i am running max rms to the sub. and open to other ideas for box design. weather that means making the box smaller or putting a slot port in instead. any help would greatly be apperciated.

[Triticum Agricolam]

I don't think a single 4" port is going to be enough. Two 4" ports would be about right, but then you will have the issue of trying to fit them in the box since they are going to have to be a lot longer.

If it were me I'd just do a slot port, that way you can make it as large as you would like.

[Joe X]

Fifth generation Type Rs work in 1.5 cubes net at rated power, 2 cubes might get rather peaky and you should try not to reach rated power. Rather difficult to do a box with round ports giving proper port area, you will find out soon.

[rogerz]

thanks i think i am going to go with a smaller slot ported box and make life a litlle easyer on myself. just have to figure out whats going to work.

My options for a slot port are:

- make 2 180 degree turns in port

or make my box deeper and put an L shaped port that goes behind the driver.

[Joe X]

Box shape and aimings depends on what vehicle, how your max dims are, when possible do the port the has the least turns, it will work better in most cases, look to have a port area of around 30 square inches.

[rogerz]

The system will be going into a mazdaspeed3 so smaller hatchback car. im going to shoot for a box that is close to alpine recomended specs. only thing i dont know about and maybe i should do a little more reseach about it is that alpines recomended port area for the type R is 12.5x1. is a one inch wide port to skinny? or does it not matter as long is the area and volume are the same.

the sub and port will be rear firing torward the hatch.

[Nightshade]

If it were me I would run the Type R in 1.7 cubes with a single 4" port. That will give you 7.4 sqin per cuft and IMO that is a very nice ratio. For example in my current box for 2 sa12s I am at 2.8 cubes after all displacements and I am running 2 4" aeroports. This is 8.97 sqin of port per cuft. The car does well over a 150 on the dash too and is peaking at 46-48hz depending on the day.

If you wanted you could try 1.7 cubes with 2 3" aeros. That would give you 8.3 sqin per cuft and is a slight bit better but may not be that noticeable in the end off lower power.