newguy, but whats is the REAL volume in there?

[RVjupiter]

fist time caller to the show.
it's wonderful to find a total wealth of information here, and i am still new to the DIY sound concept with a question about the real volume in the cabinet.

how much space is really taken up by the extracurricular components, and is it really something to worry about or not? If the math comes out with a perfect .5 cubic foot box for my needs, and then i put an internal brace, a crossover, wires, and the tweeter motor takes up some space...well what am i left with? and if i'm shooting for as perfect as i can get, wouldn't i want to compensate slightly in box measurements? i'm just trying to get as much as possible with what I got. i did some searching under various terms and came up nothing.
thoughts?
am i splitting hairs?

my project is going to be something nice and bookshelf-ish but i will be mounting the tweeter (a very good one, not the HiVi.) separately on top in its own padded small enclosure (to dampen its own returns and not be interfered with by the driver and it's waves.) in plane with the driver cone center. i just think it's more efficient that way.

[Godzilla]

When adding bracing i always figure it takes away a bit of volume when i calculate. I usually just round off a little. When you use a program like WinISD you will see slight variations in volume do not really change the response you get from a speaker. Enjoy.

[Lsharptec1]

RVjupiter,

Godzilla makes a good point.

I usually add 10% to the total box volume for braces, crossover network, etc.

Zilla, it's great to have you back, stomping Tokyo flat.

Larry

[Svante]

The volume taken up by driver, vent, bracing etc should be removed to get the effective volume of the box. Then this volume should be increased a bit if there is damping material in the box (that has an isothermalizing effect). These two things counteracts one another, and compensating for just one of them might actually turn out worse than skipping it all.

...then again one should be aware about how small effect these small box volume changes has on the frequency response. Typically it turns out that the difference is rather small, within a dB or so.