I'm in the middle of taping up my trunk to do a fiberglass box. I'm using the packing peanuts in a bag method of estimating enclosure space. Right now I've taped up something a little too big (bigger than the bag takes up). The unknown factor right now is how thick it will end up and how much less volume I will end up with when actually built.
I know that if you build it too small you have the option of cutting off a side and expanding it with new fiberglass. Sounds time consuming but doable.
I think I will end up with a little extra space - so what is the easiest option to fill in space once I have built it and tested it for strength and internal volume?
Like to plan ahead so thanks for the advice.

 

You don't have to nail the volume to within a nat's behind.

Get as close as you can and if you're just a bit off you'll never hear the difference. You will notice if your formula's call for 1" poly stuffing and you don't use it. Depending on the size of your box a few square inches one way or the other isn't going to make enough difference to worry about it. Really small boxes do color the sound a bunch.

If you're really concerned build the box slightly bigger than what your formula calls for. Then measure the interior size to find out how much "too big" it is. Then cut yourself a piece of lumber the right number of cubic inches in size and glue it to the interior back.

 

thanks. That's what I was looking for, an easy way out if I need it. Hopefully I won't, I've heard you can be off by up to 20% either way. I think I would rather it end up just a little too big personally.

 

bigger is better than too small



flatten out the response curve

 

I'm sure that response has been said many times to other matters as well.