tuning hz

when trying to optimize the flatest response in a slot ported box, does this benfit all types of music or is it just better for some.. i mainly listen to rap so i wanna tune it for that. What also is a popular tuning hz....

help... does this look rite for a type r 15 box

net vol - 3 cu ft,  tune to 33 hz, port width 3.75 ", port area 61.875 sq in, port lenght 44.5 "

external dimensions 48 " wide, 18 " tall and 12.75 deep.

The thing about rap and most of the popular music like it is that the boost in frequencies are already built into the recording.  Someone with a cheap little system hears the boom greater than the sum of all other parts.  You don't really need to build more boost into the enclosure, and you also don't need to use boosts on the amp either.  Choosing the flattest response possible (within reasonable size limitations) will yield good results with rap as well as other types of music.

You'll want to check to see if you need a port opening that large, as the length is long in response.  The total cu ft of port in that box is big and has to be added to the overall structure volume.  Modify your WinISD rear port velocity chart to read ft / sec and rms instead of peak.  Input the actual power that will be applied in the signal box.  Keep the port noise at 110 ft / sec or less.  You might find that a smaller opening will work and thus decrease that port length.

The first thing to look at when deciding whether to use a sealed or vented enclosure is the EBP.  The EBP is Fs / Qes.  In this case this sub has an EBP of 48.  Anything below 50 should use sealed, anything above 100 should use vented.  The range between 50 and 100 is a call, but with the lower EBPs you find that the port grows to very long proportions.  That is what is happening, it looks like, in your case.  You want to vent a box for this sub when it should rather use a sealed box.

Look at your driver parameters and verify.  Also, when you input the correct parameters in WinISD, the program chooses the type of box by default.  I would think that the program would have chosen sealed for this sub. 

I looked at the specs on the website for the 2004 Type R subs because that is all they showed.  If you have something different post the model # and a link to the parameters info.