Jonathan_ED3

How do you determine what size the box will be before you start building?

More importantly, how would I determine exactly how big a space I would need to mold from in order to get a desired internal volume?

The only way I can think of to get the 'exact' volume would be to fill it with water....but you obviously can't do that until after the box is built.

Is there no way to get it exact, nothing more than rough guestimation?

nsxxtreme

You seem smart you can rough gestimate how big your box will be. Then as you say use water to calculate the exact size. Taking volume away is easy just fill it with something. Adding more volume requires more work. After a while you get pretty good at guessing volumes.

rcurley55

Grab enough packing peanuts to fill the area that you want to use for the box. For example, if you are doing the spare tire well, fill it to the top loosely with peanuts. Then get a cardboard box. Transfer the peanuts to the box, and with some math, you can determine the approximate size of the well.

nsxxtreme

Good idea for a rough estimate never thought of that. For a tire well i just use pi*r^2*h it gets me close enough.

baldylox

do a google search for some box calulators....i found one long ago that worked with trapezoidal volumes and crazy type shapes. my box was kinda trapezoidal in the wheel well. the calcualted volume vs what i think i have was within .3ft cubed.

check on termpro.com...someone there will know some good calculators real fast.

ArizSun21

You probably already know this but just meantioning in case you forget...you must also find the volume of the sub since it will be inside the box.

Jonathan_ED3

WTF?

Seriously?

I've been building boxes for like 5 years now withOUT figuring in the space of the speaker itself.

I was told all the new speakers come with the airspace volume of the sub already figured in.

Is this not the case??? LOL man I cannot believe this to me.

You actually have to figure that out? I mean the manufacturer doesn't include that spec?

nsxxtreme

Most of the time they give you the volume of the speaker. But it is not included in the volume required by the speaker. You could mount the speaker with the magnet pointing out of the box. This is why they don't include it for box volume.

Jonathan_ED3

Oh I see....well, I learned something new today. lol.

What's the volume of the speaker labeled as?

rcurley55

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by nsxxtreme &raquo;</TD></TR><TR><TD CLASS="quote">Most of the time they give you the volume of the speaker. But it is not included in the volume required by the speaker. You could mount the speaker with the magnet pointing out of the box. This is why they don't include it for box volume.</TD></TR></TABLE>

Slow down skippy

Not ALL mfg's use net box sizes - some (Image Dynamics being one of them) give you gross box sizes - meaning build a box that size, throw in the sub and you are find.

So, if the box size is listed as NET, it doesn't take the subwoofer volume into account, so you must make it the Net Size + volume displaced by the sub.

Sorry to split hairs, but it could affect box tuning on some designs.

nsxxtreme

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">Not ALL mfg's use net box sizes - some (Image Dynamics being one of them) give you gross box sizes - meaning build a box that size, throw in the sub and you are find.</TD></TR></TABLE>

that would be fine.

Sorry to split hairs, but it could affect someones ability to read.
That's news to me. I wish the audio industry would chose a standard. I think they do it on purpose so as to confuse the consumer. This way you will by bunk products until the learning curve catches up. By then they are onto the next bunk product. Kind of like the huge capacitors they sell.

LOL just joking around rcurley

Jonathan_ED3

lol, so how do I know if the specs are 'gross' or 'net'?

I've certainly never seen anything of the sort.

All I ever see is 'recommended sealed volume', and that's IT.

So how do I know?

rcurley55

lol

When in doubt, assume it's Net. For example, JL audio lists net sizes, but when they recommend enclosures with dimensions, they do include sizes, so you just have to read the spec sheet carefully.

Most MFG's love to have confused customers - it allows sales people to make more money

xXxS_SxXx

best way for me was i called rockford for box sizes and spec spent a 1/2 hour going over the box specs and proper port location and port size for the subs i was using and that was time well spent that box was the best box i ever built much props for rf techs