slot port box for 10" type R question

[ColumbusJBR]

Hey guys,

Gonna attempt first box build in near future, slot port box for my swr 1022D. I have yet to get the exact measurements for my trunk, but I figured for now I was just gonna go w/ Alpines rec. specs or close to. Alpine calls for a 12.5 x 14.5 17.25 external box with a 1x11x22L slot port. Puts box at about 1.0 cu ft net, about 34 hz, if I punched it in torres correctly. All sounds good to me, I originally wanted to go for 1-1.25 cu ft @ 32-36 hz, but...

Question: The 1x11 port has me concerned. I keep reading that you don't want to go over a 9:1 ratio or you may come into some noise. Should this concern me, or should I trust that Alpine knows what they're talking about?

Thanks guys!

[Guest]

its not just the 1x11 port you should be worrying about. you need to have about 14 square inches of port per cubic foot. you have 11 right now. that can attribute to port noise, as well as a port thats very skinny.

alpine box specs suck. as do a lot of other mainstream woofer box specs

[ColumbusJBR]

alpine box specs suck. as do a lot of other mainstream woofer box specs

Good to know, thanks. I'm gonna measure my trunk shortly to see what I'm workin with and report back. My current prefab box is about .85 cu ft @ ~40 hz. I'm shooting for around 35 hz, and bigger. Just not sure exactly how big, I'd like a little better low end extension than I have now, and I gotta measure to see whats feasable. Not much room in the Prelude. You think 1.5 cu ft net is too big for a 10" type R?

Thanks for any advice

[ColumbusJBR]

I Figured the following with the RE audio calc.

alright, here are my measurements in the trunk:

Height: 12"

Width: 24"

Depth: 14"

The height and depth are constrictions. Width has some wiggle room. If I use those dimensions with a slot port of:

Height: 10.5"

Width: 1.75" (6:1 ratio)

Total port length of 24.875" (L1 = 11.5" L2 = 10")

With 0.75" mdf this gives me (according to the RE calc)

Port area: 18.375 sq in

net volume (after port displacement and sub displacement): About 1.35 cu ft.

port area per cu ft = 13.6 sq in/cu ft

tuning: 34.8 Hz

It also gives me all the sheet cut dimensions, handy. Am I on the right track? Is the RE calc pretty reliable for a simple box like this? Should I stick with the Torres calc? (I get slightly confused when it asks me to enter port length)

I'm new at this, so any and all constructive criticism is much appreciated.

Thanks guys!