sub box for 4 sa 8 v2s, is this design okay?

[skippy90210 10+ year member]

It's 35" Wide 15" Tall And 18" Deep With A Port 12" Wide By 3" Tall And 18.75" Long It's Supposed To Be Tuned To 32 Hz With 3.2 CUbic Feet After All displacements The Subs Take .32 Cubic Feet Idk How Much The Port Takes Up But Does This All Sound Right I'll Post PiC Of A Design I Drew Up

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[skippy90210 10+ year member]

Here's A pic

 

[skippy90210 10+ year member]

IMG_20140505_100610_657_zpsb9d7c493.jpg Photo by stephen_rainelli | Photobucket

 

[ObTechAudio]

So after doing my math I got an internal box volume of 4.3 cubes. You say 35" which = 33.5" of internal space (subtract .75 per sheet of MDF if you're using 3/4 MDF).

So 33.5 x 13.5 x 16.5 = 7,462 cubic inches or 4.3 cubic feet. Now, Sundown says all 4 8's will take up .32 cubes. Now we're at 4 cubic feet of internal air space.

Now let's tackle the port. You say it's 12" wide (but you now must add .75 to each side for 3/4 MDF. However, you only need to add .75 once to the 3" height, because the bottom was already calculated above). So, 13.5 x 3.75 x 18.75 = 949 cubic inches or .55 cubic feet. Your port is taking up .55 cubic feet of internal air space.

So, we had 4.3 cubes of internal space - .32 for sub displacement = 4 cubes - .55 for port area = 3.45 total internal air space. (If my calculations make sense). There is a 99% chance that I'm a dumba$$.

Sundown recommends .75 cubes ported per 8" so technically they would recommend 3 total cubes over 3.45. hat being said, you're tuning it lower and I'd imagine you're going to pump some serious power, so I think you can get away with a box around 3.2-3.4 cubes. I'd suggest making it a tad bit smaller, just a tad!

Other than that, the box looks awesome and mean!

 

[skippy90210 10+ year member]

So after doing my math I got an internal box volume of 4.3 cubes. You say 35" which = 33.5" of internal space (subtract .75 per sheet of MDF if you're using 3/4 MDF).
So 33.5 x 13.5 x 16.5 = 7,462 cubic inches or 4.3 cubic feet. Now, Sundown says all 4 8's will take up .32 cubes. Now we're at 4 cubic feet of internal air space.

Now let's tackle the port. You say it's 12" wide (but you now must add .75 to each side for 3/4 MDF. However, you only need to add .75 once to the 3" height, because the bottom was already calculated above). So, 13.5 x 3.75 x 18.75 = 949 cubic inches or .55 cubic feet. Your port is taking up .55 cubic feet of internal air space.

So, we had 4.3 cubes of internal space - .32 for sub displacement = 4 cubes - .55 for port area = 3.45 total internal air space. (If my calculations make sense). There is a 99% chance that I'm a dumba$$.

Sundown recommends .75 cubes ported per 8" so technically they would recommend 3 total cubes over 3.45. hat being said, you're tuning it lower and I'd imagine you're going to pump some serious power, so I think you can get away with a box around 3.2-3.4 cubes. I'd suggest making it a tad bit smaller, just a tad!

Other than that, the box looks awesome and mean!

i appreciate the fact you went through all that to help me and im very glad you took the time to explain that, i was also gonna put 45's in the box which will take up some space too but idk how much also if i make it smaller should i just take like a half inch or so off the back making it 17.5 outside and 16'' on the inside?

 

[skippy90210 10+ year member]

also im good with designing nice boxes but not as much with getting the math right to actualy build them;p

 

[Popwarhomie 5,000+ posts]

You could always use aero ports and make the box quite a bit smaller(way less port displacement)

 

[skippy90210 10+ year member]

You could always use aero ports and make the box quite a bit smaller(way less port displacement)

i do like aero ports but with this box i just like the look of the rectangular port plus there is no space issues i need to worry about and i want to save the money haha not a bad idea though^

 

[ObTechAudio]

Haha and I **** at designing... To be honest, if you're putting in 45's, I wouldn't make any of the dimensions smaller. They will probably take you to the 3.2 range after you put them in.

 

[skippy90210 10+ year member]

Haha and I **** at designing... To be honest, if you're putting in 45's, I wouldn't make any of the dimensions smaller. They will probably take you to the 3.2 range after you put them in.

thats what i was thinking in the begining haha but since this is only my second box build i wanted to post about it to make sure my math was right also i wouldnt mind getting more into box building but im not that smart haha i can build them thats about it but i made that design in the picture in about 20 min on a program called auto desk inventor its about 10 grand if i remember correctly but does literaly anything you could ever imagine and i get it for free through my school so thats a +1 for me!

 

[ObTechAudio]

thats what i was thinking in the begining haha but since this is only my second box build i wanted to post about it to make sure my math was right also i wouldnt mind getting more into box building but im not that smart haha i can build them thats about it but i made that design in the picture in about 20 min on a program called auto desk inventor its about 10 grand if i remember correctly but does literaly anything you could ever imagine and i get it for free through my school so thats a +1 for me!

Yaaaaa.... about that..... how can I get into that school? haha

 

[skippy90210 10+ year member]

Yaaaaa.... about that..... how can I get into that school? haha

If You Are In High School Still Then Move To Central Pa and There You Go lol