>     hello everybody
Hi!
>     i want to build some speakers for home use and i need to know what
>     size boxes to put them in.
>     i plan to put in a 12" woofer, a 6" midrange and an 82mm tweeter.
>     what size box would be needed for this combo ?
>     any other ideas or suggestions ?
There is no simple answer...
It is not just the physical size of the speaker.  There is also the
mass of the cone and the stiffness of the mounting as well as the DC 
resistance and the electrical impedance of the voice coil.
These affect the frequency response of the speaker and the frequency
at which it resonates.
The speakers have specific mechanical and electrical properities.
Each speaker has different properties.  You must match these
properties to their enclosures.  There are books which cover this 
subject and these characteristics are easy to measure with some basic 
test equipment ( audio oscillator, voltmeter and some hand-made 
resistnace guages )
Putting just any speaker into just any box will result in a very 
spikey, inefficient system.  It will work but an inch off in one 
dimention will make the difference between something OK for background 
music and something that sings!!!
If you have web access, check some of the search engines for
"speaker" "build"  and see what comes up.  Try your library and if 
there is a college or school near you with a decent science 
department, they may have a book on speakers in their library.
Good luck!
--- Via Silver Xpress V4.4 [Reg]
---------------