Box deisgn help

[someguy]

Hi guys i am new to this site and this will be my first time at attempting to design and build a subwoofer enclosure and i would highly appreciate youe help wisdom and guidance

This system will be for my father he loves music i would like to keep it as small as possible i have been researching some of the calculators but i ran into a couple issues

1 internal volume on alpine sheet says 1-1.5 but 1.7 reccommened

2 port size i've read that a wider port is best but how wide or how small is acceptable

3 he would like it to face down but with the restrictions of space i was thinking that face the subs to the back of the seat with the ports aimed up or down not to the front

4 will it be better to use a round port vs a square port

Well this is what i have to work with

vehicle is a 2001 chrysler voyager

2-12 inch alpine type r subs

48 inch wide max

14-16 inch high preffered but 18 inch max

10 inch deep preffered but 12 max

[someguy]

Also the 2 boxes i came up with is

1 16"w by 16"h by 10" deep 1.5" port by 29"

2 24"w by 16"h by 10 deep 2" port by 27"

[someguy]

Theses measurements are for one a single speaker on one side divider will seperate speakers

any help would be appreciated Thankyou in advance I have already bought the tools and material to get started just have to make sure i have enough volume and enough port for this to become a reality

[timc31610]

If you are building two separate enclosures they should be the same to avoid any cancellation. From other threads involving the type r's the will like a little larger than recommended net volume with fairly low tuning.

[Weigel21]

The range is 1-1.5cuft Net, and you seen the 1.71 ideal Gross volume, which would equate to 1.38 Net.

Porting, there's a radios of what's recommended/allotted. I want to say something like a 5:1 ratio is acceptable, but ideally one would want a 1:1 (perfectly square port, if opting for a slot port) What the dimensions would be depends on the port ratio you use and then the total port area you need. I tend to hear that 10-14sq inches of port fer cuft of volume is recommended.

Downward facing subs are great if you are opting for a sealed sub setup, but you speak of ported. I would think that in a mini van such as he has, subs face up or rear, same goes for the port, but I'm not ported enclosure expert.

I'm not so sure there's any particular benefit of one over the other in terms of sound/air flow, ect, but there probably is and I'm just ignorant of it. However, with a slot port, it's a little easier to incorporate a long port with the use of a bend (best to have 45* bends) than it is with tube ports.

May want to download Torres box calculator to assist with enclosure calculations and perhaps WinISD to assist with plotting a response curve of various enclosure/tuning combinations. Cabin gain isn't factored into the program, so it's not terribly accurate, but it can clearly show you when you have a very poor enclosure.

According to timc31610's response, the Type-R may well prefer an enclosure with roughly 1.4cuft Net tuned around 32-34Hz.

[someguy]

sorry i explained it wrong this will be one box with seperate cambers for each speaker with 1 port per speaker, identical left right side speaker

i fraised it this way because i mostly see dual speaker enclosesures with 1 large port, which i can do it this way

i did use a sub box calculator re box calculator

and thank you on explaining it needs more cubic feet for it to respond well and the spec sheet says 1-1.5 cuft and recommended 1.7 cuft i just wanted to know if i can get away with thebox i designed

[someguy]

im thinking of doing 1 port in a box with two type r speakers (side port) new dimensions will be 48 wide x 14 high x 10 deep

now i gotta find a calculator that works

[Weigel21]

Is that external dimensions?

If so, that equates to roughly 1.38cuft gross. per chamber, but doesn't account for any sub or port displacement.

You are aiming for roughly 1.8cuft Gross per chamber (before sub and port displacement), you're lacking nearly half a cubic foot of adequate internal volume.

Edit.

You may want to pay a bit more attention to the use of Net and Gross.

[someguy]

i understand thats why i asked the question so instead i had 24w by 16h by 12 deep i think thats 1.7 cubic feet port volume was always taken into account not speaker

[Weigel21]

Sorry, I only calculated the latest measurements you posted in post number 7, but failed miserably to clearly read that you specified a side port and not a center port, so my calculations were off.