I am going to make a ported box for 2 12" Alpine Type R's.
I was thinking around 3.5 - 4 cu ft shared chamber tuned to around 40 hz.
Is 40 hz too high? Should i go lower?
This is not going to be for any competitions or anything like that.
If anyone could comment on the box size and tuning i would appretiate it.

30 to 35hz

The lower the better, around 35hz is a great tuning frequency for most cars, because it's almost an octave away from the resonant frequency of the vehicle, giving you a flatter response.

i'm tuned to 32 Hz [img]smile.gif[/img]

cool, how does it sound?

which model type r's

Thanks guys, 35 Hz sounds like a plan to me.
But would anyone recomend sealed over ported for two type R's? Someone told me that they sound better sealed rather than ported. Is this true?

model SWR-1241D

Matter of prefference:
sealed= +higher power handling, flatter response
smaller box, quicker bass. good for
rock, metal, country, most music.
-not as loud
Ported= +boomier, more efficient, 'sounds' deeper
better for rap, dance etc.
-slower transient response, bigger box.

Type R's sound great in both, but if you have under 300 watts, go ported

the sealed box will sound great1.5-1.7 cubic ft for the pair, a vented box 4 cubic ft net internal, not icluding bracing with dual 4" ports 13.75" long will give you some great deep bass extension at the sacrifice of good upper bass response, aka better have a killer midbass set up with the vented box, you zr240 should power them well in sealed but great vented, its up too you, good luck