Okay this might be a dumb question but here it goes. If a ported box is tuned to 30Hz what exactly does that mean? Does it mean that if I'm listening to a song the sub will only play out the bass tones at 30Hz or below and not play the bass tones of anything above 30Hz? Can someone please explain? Also how do they tune ported boxes to a certain Hz?
the box is more efficient around 30hz. the farther away from 30hz the less efficient. find the resonate frequency of your vehicle and tune the box to that.
You also tune to your personal preferance. If your gonna make a huge spl box for competition, then you'd probably tune it to 60 or 70 hz. If you have a very good quality sub that plays awsome lows, then you'd tune it to maybe 25. If you have an average sub that might not play the super low notes as well, then you might tune it 30 - 35. My ported box is tuned at 35. The very low notes aren't nearly as loud as my friends sealed eclipse, but the mid and higher bass is extremely loud.