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Building
the Perfect sub box
by
Vince Cuffaro
Ok...seems some of you want to take on the challenge of building your
own sub box. Well, here are some good pointers for anyone wanting to
take on this, sometimes daunting task!
I have always built my own boxes. I also have used the MECP manual to do
it. so these are how they are SUPPOSED to be done!
I have also had great success with them, and have made single sub
systems that will out pound ANYTHING around! (blowing my own horn
rules!)
First off, as someone mentioned, it is VERY important to build the box
for each individual sub. what do I mean? well, a Kicker sub will need a
different type of enclosure and size than a Autotek...or Rockford...or
whatever! I never go by the website info...I call the manufacturer
directly, if possible, and ask the tech department EXACTLY how big the
box needs to be to make the sub work....also ask what type of
enclosure...sealed, ported, bandpass. This is very
important!
The next big step is the box itself. I used to use a dense pressboard
...a lot of little particles glued together. However, the
recommended product is MDF or Medium Density Fiberboard. I am in the
process of building a new enclosure now using my wheel well and I
decided for a couple bucks more to use MDF. Make sure to use no
LESS than 1/2 inch MDF! preferably 3/4 inch!
The biggest part of making the enclosure is volume and making sure it's
the right size. you have to account for the walls of the box when
calculating space. how do you calculate box volume? measure your box
idea, it's easy if its' square/rectangle, as opposed to multi faceted as
the new one I'm doing!
Basically start with a box size you'd like to use and measure length
x width x height to get total cubic inches. then divide that by 1728....that
is how many cubic inches are in a cubic foot! so for example lets say
you want to try and make a box that is 15 x 14 x 8....so that is: 1680
cubic inches...divide by 1728: .97 cubic feet. so if
your sub needs 1.5 cubic feet you'll have to think bigger! but...if the
sub required 1.0 cubic feet you can fix that by adding fiber fill. this
will make the sub 'think' the box is bigger than it is....but I would
redo the box size and not go that route unless
absolutely necessary for room! and don't forget that the walls of
the box must be added in....or make sure the INTERNAL volume is
being measured and NOT the overall volume! for instance if you have 20
inches of measurement per side l x w x h...you'll
have 4.6 cubic feet...if you forget about the 3/4 inches MDF you'll wind
up with 3.6 cubic feet! that is a BIG difference! and could be costly!
And be sure that each sub is in it's own enclosure...build a big box and
wall it off in the middle.
when trying to mess with Plexiglas, good luck! you'll need to cut it and
figure out a good way to mount it! never messed with the stuff...never
will! you'll also need at least 3/4 inch of it!
After you've gone through all the hair pulling from measuring, and re-measuring
(don't get this wrong! better to take your time instead of having the
wrong size box!) it's time to cut and put together your box!
the way I do it is a little more time-consuming and you need the right
stuff, but it works for me. you might find a way to do it easier for
you, but just be sure the box has NO air leaks and is solid....
I cut my MDF with a table saw, or jig saw, making sure the sides are
straight
as an arrow! be sure to layout how you will adjoin what side to what
before
you do this so you have the right size pieces! and be sure to account
for the
material thickness as well! my first box I 'thought' I needed a 20 inch
side...then realized AFTER I cut it that it needed to be 21
inches....1/2 inch of
MDF on either end!
anyhow, just be careful here with the saw as well!!! lost limbs are NOT
my or
Purehonda's problem! (see attached legalese!) hehehe....
what I then do is make sure all the sides fit ok...and mark the tops for
screws.
I will use drywall screws and Liquid nails.
I place the screws along the sides to be attached evenly. I then take a
drill
bit that is designed to counter sink a hole...so the tops of the screws
will be
flush. Need help on this ask....
I then apply a bead of liquid nails...or wood glue...and screw it together!
DON'T
use liquid nails or glue on the box lid...the one with the sub holes! I
use a this,
sticky sided insulation and then screw it...you might need to get that
top off
one day!
oh, if you have a nice terminal assembly for the speaker wires cut that
hole
out as well...if not what I've done is drill a hole just big enough to
squeeze a
wire through it and then liquid nail the wires in place...
when cutting out the speaker holes be sure to measure from the INSIDE
edge
of the mounting ring...just outside the foam/rubber surround! DON'T make
it
too big or you'll be in a big mess!
after the assembly, I run a bead of liquid nails along the inside
corners of the
box. can never be to safe!
Let everything dry for at least a day....
before you put the top on, go get some carpet underlay. you know the
stuff
under your Honda's carpeting? you can get it at the local hardware
store. it's
the fabric kind..NOT the foam! looks like millions of threads in
different colors
all mashed together? looks kind of gray in color mostly though. I use
about 1/2
inch think.
I'll take this and cut squares the size of the inside of the box sides.
then use a
staple gun to staple it a few times in place.
this stuff works great to help further dampen the box and DOES have a
NOTICEABLE difference over non damped boxes! I've tried it!
this is not to be used in place of polyfil. although, like I said, don't
use fill
unless the box is too small or you need to make the box smaller for
space. I
might even try messing with polyfil..more, less, none, some. Sometimes
subs
can be finicky and work better under certain circumstances....
when putting in the subs, make sure the connections are secure! sucks
having
to go back into a box to redo a loose wire.
I also use at least 10 gauge wire for my subs...and will use 8 guage or
maybe
even 4 in the next enclosure! The more wire the more power....especially
with amps!
Then carpet your box or leave it and enjoy!
I think that about covers it....any questions please ask! Like I said
before,
there are alot of ways to do this, but this is based on the MECP
installers
training book! I read it like the bible when doing my first system.....
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