Volume Question

[Flipx99 5,000+ posts]

Is Vas the same thing as displacement?

 

[mrray13 10+ year member]

what are u trying to figure out exactly?

vas is something more complex then vb...

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[Flipx99 5,000+ posts]

I found it listed finally.

I am going to take your advice and do the ported box thing. It doesn't bother me really and I may be able to use the sub as a replacement or something so it isn't hurting anyone just sitting there.

I looked into one site that does boxes. I belive it is by beerman. When I look at the pic, it is a bunch of lines that go up and down and I don't see where you are supposed to put the sub. It also has a port lenth that is longer than the box. I am not sure what I am looking at here. Here are my specs:

Width- up to 42"

Height - up to 16"

Depth- up to 24" (also depth isn't an option on the box)

12" sub

xmax - 12.7mm

driver displacement - .083cf

reccomended volume - 1.75 cf

qts - .33

vas - 1.22 cf

fs - 30 htz

What is the difference between the teal bars and the violet ones?

 

[hoss 5,000+ posts]

the volume of air that is the equivelant to the suspension...

an easy way to think of it is this, if youre box volume in a sealed enclosure is equal to the VAS, you might as well be running infinite baffle.

 

[Logikalliquid 10+ year member]

im slow, ignore this

 

[mrray13 10+ year member]

the volume of air that is the equivelant to the suspension...
an easy way to think of it is this, if youre box volume in a sealed enclosure is equal to the VAS, you might as well be running infinite baffle.

u put it into words alot better then i could've..lol....which is why i didn't try...

flip...basiclly, ur going to need a 3.5ft^3 NET enclosure for a pair of twelves.

i'd suggest tuning around 34-36hz to achieve the best compromise of sq and spl..

40in^2 of port should be plenty for two of those subs...

and if u get a port length longer then any inside box dimension, u bend it..lol..either "L" shaped, or labrinyth style...u can, of course, use round ports and get away with less port area, say two 4" round ports, and they will also be a touch shorter...

wheeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee :slayer:

 

[Flipx99 5,000+ posts]

When I said depth isn't an option, I meant on the utility. I car build it as deep as necessary.

 

[Flipx99 5,000+ posts]

I see. I beleive the "labrynth style" is what the pciture is depicting. Now if I can figure out what the colors mean and where the subs go I'll be all set. Thanks for your help. Here is a link to what utility I am using.

http://www.accelerator-pedal.com/ported-box.asp#

 

[mrray13 10+ year member]

here's on u can build....

15" tall x 35.75" long x 16" deep, with two 4" round ports x 12 3/8"long (assuming shd 40 pvc), gives ya 3.5ft^3 net, tuned to 35hz

or if u slot port it....

15" tall x 38.75" long x 16" deep, with a slot port 13.5" tallx 3" wide x 18.75" long with net u 3.5ft^3 tuned to ~35hz

hope that helps a bit.....and this assumes no bracing and 3/4" mdf...

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[Flipx99 5,000+ posts]

How do you make the " L " for creating depth in the ports. L brackets? Or screws, but it looks like it would make it wobble.

Here is an attempt on what I am trying to explain:

|

|

_______|*_______________________

/\

| --- is all I have to is put a screw here or do I also need L brackets at the *

Or do I have it all wrong and port does not have depth?

 

[Flipx99 5,000+ posts]

The line should be even with the *, for some reason it did not come out right. If you give me your e-mail I can send you a pic of what i am trying to explain.

 

[mrray13 10+ year member]

ummmm, well,when finished, u won't need any brackets as teh box will hold it in place..(u'll screw into the top and bottom of the port wall from the outside)

i take it u've never built an enclosure? or at least a ported one?

u might be better off having someone build it for u.....

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[Flipx99 5,000+ posts]

I can structurally build things if I know how they come together. I built a sealed one before and it works out fine.

I see how it works now...I believe....I am going to see if I can find some pics of ported enclosures from the inside.

It may be easier to do the round ports...because they sell them.

 

[mrray13 10+ year member]

I can structurally build things if I know how they come together. I built a sealed one before and it works out fine.
I see how it works now...I believe....I am going to see if I can find some pics of ported enclosures from the inside.

It may be easier to do the round ports...because they sell them.

correct, but flared ports figure differently then just round ones...

and i'm not trying to doubt ur building ability, but just making a suggestion..no offense intended.

finding such pics will be helpful...

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[Flipx99 5,000+ posts]

I found some pics and see more how the vent extends the depth/height of the box, not just a dimple. Is there advantages/disadvantages to placement of the port?