Enclosure Specifications

I know no-one really has the time to help me understand this so I understand If I get no responses. I asked this of another car audio forum and was told to go back and read the basic's of car audio.(which may be true)yet without doing all that I think I can get past this one question.

Basically if you could look at this page, and then scroll to the "Enclosure Specifications"   this is the part I'd like to understand about this subwoofer and it's box.

this is the page link:

http://www.imagedynamicsusa.com/website/tech/data_sheet_idq12d2v2.html

basically if I stick the sub in a 1.0 cu ft. box then I will get 14Hz/40Hz...

 hmmm I'm still looking for what -3db in car/free space means in basic car audio literature...can't find it...help

3-dB bandwidth (half-power bandwidth) is the typical standard way of looking at filter characteristics.  For example in a low-pass filter, the 3-dB bandwidth is defined as the seperation between zero frequency, where the amplitude spectrum attains its peak value, and the positive frequency at which thae amplitude drops to 1/sqrt(2) of its peak value (.707).  The reason they rate things with the 3dB bandwidth, is can be read directly from a plot of the amplitude spectrum.   I would also recommend reading some books about enclosure design (loud speaker design cookbook is always my first choice), but it can be somewhat confusing depending on the level of math you have and amount of basic electronics knowledge. 

let me know if I can explain this stuff any futher or better, I didn't really know where to start, but hopefully that gave you a bit more direction. 

I will leave it up to you to make the interpretations based on my definition.

Craig

thank you...your one of the good guys!

I was thinking about buying a book online the other night, I forget the name of a book  that heard of a while back, it seemed to be pretty good stuff concerning car audio...it is supposed to be like the bible of car audio. I will have to do a search.

as with anything in life, it will be confusing yet as long as you stick with it, it will all make sense eventually...usually.:)

thanks again,

later

THere are a lot of "good" books about electronics....I would recommend learning your basics, (like KVL, KCL, circuit analysis etc) then move to a book on signal processing and filter design.  From there you will obtain the tools to take on larger goals like, accoustical theory, imagine theory all sorts of fun stuff like that.  Plus along the way you will pick up a bunch of math skills that will be very necessary to do your own design work.

If you ever have math/ or circuit questions, filters whatever,  I will be more than glad to try to put you in the right track.

Craig