veeman

iTrader: (3)

No, Crutchfield aquired those specs from Alpine directly because they don't specify a vented box for those subs. As such the information reads that within the range of box sizes(0.6-1.25 cuft), Alpine recommends 1.0 cuft with a 3"x12"(sorry I think i said 10" earlier) port. I read that as gross box volume including driver displacement, and port volume. Therefore, I would build a 2 cube gross internal box with 170 cu inches of port volume. This will yield the same tuning and performance as their recommended box. Note: because the round ports' cylinder wall takes up very little volume, and your slot port wall will take up more(depending on wood thickness), you should add the port wall volume and any other internal bracing that you add for strength to the gross internal volume. Hope that clears it up for you.

steve_o1989

iTrader: (1)

Ok I figured out that Alpines spec on the box which is the 1ft^3 with the 3x12 port gives a box that is tuned to about 36.5hz.

To make things simpler for me (I am so damn confused right now lol) Do I take a 1ft^3 box, figure out the tuning frequency for that, add the port volume and the port wall volume and the sub displacements to initial volume and build a box that size?

So if I have a 1ft^3 box + .05ft^3 port giving me 36hz + .05ft^5 subdisplacement + .05ft^3port wall, I build a box that is 1.15 internal volume. Once all the displacements of everything else are brought into effect, I will have a box that is 1ft^3 and tuned to my desired frequency?

BTW all those numbers I used it that example mean nothing and were just for example. The only thing that stands is I want a 1ft^3 box tuned to 36hz

veeman

iTrader: (3)

yes, tune to your net volume. Then add all the additional volumes to get your gross box. I assume you're using WINISD, or something similar? Keep in mind that you'll get close but it's never exact. It really does not matter too much as long as you're pretty close...it will sound good. I used Alpine's recommended sealed set up for 2x12'' new type r's, and I love it. I needed space so I decided to go sealed, but I think it's as loud or louder than my previous 3x12" Infinity's in a 4 cube, big port box with similar power. This box is only 1.7 cubes gross internal. Anyway, let me know how it works out.

steve_o1989

iTrader: (1)

Actually as for the WINISD, im not using it right now. Im just figuring everything out on paper. I think I have it though.

A gross box volume of 2.285ft^3 with a 2"x10"x8.5" port.

So after taking everything into account
2.285 box
-.098 port
-.184 woofer displcement
-.0033 for port wall

I get a 2ft^3 box with 170in^3 port.

Sound good?

veeman

iTrader: (3)

looks good except for the port wall. How thick is it? I get 10x.75x8.5=63.75"cubed=0.0368cuft with a 3/4" thick wall. Gross is 2.3188 cuft.

2.0
+0.184
+0.098
+0.0368
----------
2.3188

steve_o1989

iTrader: (1)

yeah your right I forgot to take into account the height. So I will shoot for 2.31cuft and see how close I can get. Thank you alot man for all the help you have given me. I really appreciate the time you took for me. It has help alot and cleared dome things up for me. Thanks

veeman

iTrader: (3)

anytime!! my friend.