Well im bored so i decided to do a write up.
Makeing A Professional Enclosure With Professional Results
If you want professional results but dont have the money to have a profesional build your enclosure or you dont want to hand your outcome to some half asses local dealer there are a few things you can do about it.
Assuming you have basic motor skills and some sort of wood working skills it is quite easy to come out with profesional results but there are a few things you will need.
-A Good Design
Design is first on the list. If the design is horrible the sound will be horrible and you will be dissatisfied. Great you can cut the wood and glue it. But all that doesnt matter if you arent even doing 135 on the AC with a single 15 in a hatch.
Every joe shmo on the internet thinks he can design an enclosure for you, 3 out of 5 times he cant. a few things to look for are
-Bracing, if the design doesnt include bracing or doesnt include exctra gross space for bracing he/she doesnt know WTF they are doing. Bracing is important if the enclosure is of any decent size, even with small/weak drivers.
-Use of 3/4" MDF, this should be a given.
-Proper port area or Transmission Line crossectional area. Port area rule of thumb is 10sqin per cuft with round ports and 12-16 for slot ports. flared round ports have a little gimme space. Transmission line (aka Snail shell and 1/4 wave length enclosres) cross sectional area whould taper down to a final area equal or with in 10% of driver Sd. Sd can be found in the drivers T/S parameters.
-Length of ports is important. i know its sort of a given but download WinISD and see how long a port should be.
-Make sure they arent drawn in paint. a simple cad program at LEAST.
-Wood Skills
(you know how to handle your wood)
A problem i see with newbies including myself when i was a newbie was not accounting for blade with when cutting the wood.
Other than that not cutting straight is usually the culprit for bad outcome, lay off the coffe or meth or w/e you are doing and concentrate. Invest in a 4ft level and a good sized square, you'll thank yourself later. Drill and countersink your screw heads, even if you are carpeting.
Remember to glue and screw, if you have acess to lots of clamps of all shapes and sizes screws arent needed if you know what you are doing. I still reccomend them though, Go ahead and leave them in, they arent hurting anything. Rule of thumb is no closer than 4" from any corner unless you must and a screw every 2-5" apart, closer and more consistant being better of course.
-Bondo
I reccomend you bondo even if you plan on carpeting. Smooth every seam and fill every screw hole. I reccomend you round corners and edges and make it a paintable surface. clean it well with acetone even if carpeting, the carpet will adhear better.
-Finishing
I highly reccomend that unless you are an experenced painter you do NOT paint your boxes. Spray paint, unless done properly and with lots of care usually looks tackey and out of place. If you must paint your boxes a good wood primer is a must with MDF or else count on doing about 30 coats to get a decent solid color.
I also advise agianst carpeting. If you want carpet learn on a shitty test box that you built. Practice makes perfect. Use the good carpet, though it may not seem like its worth it a carpet with no backing and lots of strech will make carpeting easier, and often will make it look better. Parts Express sells some decent carpet for like $3-$4 a linear yard. Also, use a good adheasive, ive heard no complaints about 3M spray adheasive.
So if im not sapposed to carpet or paint what am i ever to do? well my reccomendation is truck bed liner. Duplicolor sells a semi-gloss black for like $8 a can and works GREAT. i reccomend that your prime the box, do one light coat, one normal coat, and then, another normal coat if there are a few thin spots, then a mist to add texture. The stuf will cover any mistakes you made (well most) and 2-3 cans will do almost any enclosure you can throw at them. Also it protects the box from abuse and stiffens the wood even more.
-Polyester Resin
If you are anal or want to grab a few tenths on the mic painting the inside with polyester resin stiffens the MDF raising its point of resonance and dampening vibrations by adding mass (though normally adding mass lowers resonance point, the resin soaks into the pores and makes the MDF stiffer, raising the point of resonance). Less box flexing = louder. You can generally mix it pretty hot and between you and a friend you can mix up a half a quart to a whole quart at a time or so depending on your speed of work. Ive dont a whole quart at a time by myself but i was busting my ass to get a good even coat and not waste any.
-A Few Other Things To Note
If you have a good design, good wood working skills, resin it and make it look good the only thing that can go wrong now is placement, there are guidlines for trunked cars and hatches and SUV's butno one place is universal so try a few different places. Once you find the best place screw your enclsoure down with L brackets or internal bolts, not only does this help slightly with SPL but it makes dirty bastards work harder to jack your hard work and $400 speakers.