Audio Systems: home made speaker box, ford f 250, speaker box design

Question
I have a '95 ford f 250 standard cab with 2 12" kicker comp 2ohm dual voicecoil subs and need to know the amount of air space required. What do you recommend Sealed box or ported? If ported where should the ports be located. 1 speaker aimed at the roof and the other aimed at front window. The amp is a 1000watt mono class D pioneer. I have 12 guage speaker wire running to the subs. Should I fill the box with dycron filling and if so where do I get it? Thank you

Answer
Comment:  Vented box, properly designed, can always, according to theory, give slightly better results in the lower region than a closed box.  But, the box is more expensive to build and requires more "calculations" to get it right.  A port is needed only when the box size you chose is too small for the speakers in question.  Which is often the case in car applications due to the limited space available to put a big box.  But, big boxes are always better.  However, the difference in theoretical improvement of the ideal vented box vs the ideal closed box is often not significant enough to make a really big difference  ( a couple of db or maybe 3 db at a point just above the resonant frequency and lower).

Here is a good white paper on speaker box design vs other tradeoffs.  Take alook at it.

http://www.trueaudio.com/st_trade.htm

Here you can design the box by yourself following the applet:

http://www.ishtek.com/spkrs.htm

Here is another design calculator that is easier to use, maybe:

http://www.mhsoft.nl/spk_calc.asp

And there are others.

You will need the TH parameters from Kicker on the speakers you are using.  If you can't get them from Kicker you may have to measure them yourself.

Here is one way to measure them:

http://sound.westhost.com/tsp.htm

BUT: I am pretty sure Kicker has them available for their product.

The following page gives SOME information on a 12" from kicker, but you must determine which speaker you have and try to find out what parameters are available.

http://www.kicker.com/06/kicker_home.html

Good Luck.  Happy Designing.

Cleggsan
PS:  If you go with a port, it should be located where it can breath easy when installed in the vehicle, but acoustically it does not matter a great deal because at the frequencies it is operating the sound is non-directional.  Stuffing the box is primarily to keep the reflections inside the box from getting out through the port.  For a sealed box it will provide some increase in acoustic volume, but it is not terrible critical in car boxes.  YOu can buy insulation at places like Home Depot that will work just fine.

Lastly, there are some manufacturers that offer premade boxes that are designed for specific drivers. You may be able to find one already to go for your driver; you will have to search.  They are usually cheaper, considerably, than building one by yourself.