BMW E46 Fanatics Forum banner

1 - 20 of 22 Posts

·
Registered
Joined
·
1,681 Posts
Discussion Starter #1
I have an odd shape box that i need to Calculate the volume of.

I heard you can use water to do this. Is this true?

If so, how would i go about doing this?
 

·
Registered
Joined
·
595 Posts
I wouldn't use water, it's messy and it'll ruin your box. Use foam popcorn or sand. Then transfer it to a measuring cup. I think that how people are doing it.
 

·
Registered
Joined
·
178 Posts
i'm sure you could use water as long as you make sure you use plastic so nothing gets wet. it does sound messy. you would just fill up your box all the way with water and then start measuing how much water is in there. 1 liter of water = 0.0353147 cu ft.

i think it would be cleaner to use sand or the popcorn stuff, and do the same thing.
 

·
Registered
Joined
·
1,681 Posts
Discussion Starter #5
maybe sand sounds better.. i dunno... i'll see..


umm.. lets say i build the whole box, without the front or top. i could fill it up with sand, water, nuts... whatever.. and get the volume... and then calculate the port later on?

leaving 1 piece of the box out will allow me to do the port after i figure out the volume.

Does this sound correct?
 

·
Registered
Joined
·
1,170 Posts
sdbimmer said:
I wouldn't use water, it's messy and it'll ruin your box. Use foam popcorn or sand. Then transfer it to a measuring cup. I think that how people are doing it.
I'm with sdbimmer...

Go with the foam popcorn dude - definitely the easiest and least damaging to work with...

Mark
 

·
Registered
Joined
·
1,681 Posts
Discussion Starter #7
Canuck328i said:
I'm with sdbimmer...

Go with the foam popcorn dude - definitely the easiest and least damaging to work with...

Mark
i can figure out port later right?
 

·
Registered
Joined
·
1,170 Posts
PLAZAMAN said:
i can figure out port later right?
Yeah - get your box volume then figure out the port. Then use the chips again to measure the port volume (the part that will be in the box anyway) and recalculate to see if you have to fine tune. Also don't forget the woofer basket!

Mark
 

·
Registered
Joined
·
1,681 Posts
Discussion Starter #9
if i use sand.. do i have to compact it real well?

once i find the volume. how do you figure out the port?
 

·
Registered
Joined
·
1,681 Posts
Discussion Starter #11
rcurley55 said:
why use heavy, messy sand when you can use packing popcorn/peanuts....
i got packing popcorn/peanuts.

how do i measure this?

use a Measuring cup, fill up with packing nuts , then see how many cups fill the box?
 

·
Registered
Joined
·
1,628 Posts
well, you could do it that way, but it would be less accurate then the following:

I only use this method if it's a very irregular shape that can't be calculated by geometry.

Fill the box entirely with peanuts. Don't cram them in there, just losely fill it. Then get a cardboard b ox - one that is nice and square. Now transfer the peanuts to the empty cardboard box.

I'd recommend a cardboard box that is about a cube, and about 1 cf. Fill up the box. If it gets to the top, empty it and fill it up again. Now you can measure how high the peanuts hit on the box, you know the width and the depth of the box, so now you can calculate.
 

·
Registered
Joined
·
7,635 Posts
The most accurate way of figuring out the volume is using water. You could use other things such as sand, rice, beans, popcorn, etc. If you use small uniform stuff such as sand or rice, your measurement will be more accurate. If you use bigger, more irregular objects such as packing peanuts or popcorn, your measurement will not be as accurate.

Here's what you can do, get a solid object you can easily measure to fill up most of the volume of the box, such as a box, ball, piece of solid foam, insulation, etc. Then use sand or other object to fill in the remaining space. I use a measuring cup to pour in the sand and count how many cups I dump in (for example, use a 1 liter cup, 10 times, then you have 10 liters, which can be converted to cubic feet easily). Add volume of solid object and sand for total volume.

have fun!
 

·
Registered
Joined
·
454 Posts
i put big trash bag in the box like the way i put trash bag in the trash can. then, i pour liters of water in until i fill the box. this way, the box will stay dry.

ps. i use 2 layers of trash bags to be safe.
 

·
Registered
Joined
·
1,212 Posts
How irregular shaped will this box be? Are you building it from mdf?
If it's not curved in any way, it's pretty easy to calculate the volume no matter how odd shaped it is...

Give me measurements of all the sides it has (Cubicle has 6, your's might have more) and the wall thickness and I'll calculate it for you. :thumbup:
 

·
Registered
Joined
·
1,212 Posts
kwang125 said:
i put big trash bag in the box like the way i put trash bag in the trash can. then, i pour liters of water in until i fill the box. this way, the box will stay dry.

ps. i use 2 layers of trash bags to be safe.
If it's not a huge box, this would work out rather well I think.
 

·
Registered
Joined
·
11,483 Posts
If you're building a ported box, you'll need to know how big the box and port is first. If you build a box and then try to calculate the port size, you'll off unless you plan on using an external port... :idea:
 

·
Registered
Joined
·
1,681 Posts
Discussion Starter #19
bigjae1976 said:
If you're building a ported box, you'll need to know how big the box and port is first. If you build a box and then try to calculate the port size, you'll off unless you plan on using an external port... :idea:

Jae... Im trying to port an odd shaped box.

Are you saying for example if i want to tune a box to 33hz... 33hz of port will be 1 size no matter how big the box?
 

·
Registered
Joined
·
11,483 Posts
PLAZAMAN said:
Jae... Im trying to port an odd shaped box.

Are you saying for example if i want to tune a box to 33hz... 33hz of port will be 1 size no matter how big the box?
No, the port changes as the box size changes. The problem is that a certain internal volume can give you some crazy port size, like 4" dia x 36" long. Get with someone who has a box design program or download one to plan this out.
 
1 - 20 of 22 Posts
Top