The two common box types trade size, efficiency and control in different ways. Here is how to choose for your vehicle and your music.
Sealed boxes
A sealed box is airtight. The air inside acts as a spring behind the cone, which keeps the cone under control. Sealed boxes are smaller for a given subwoofer, roll off gently below their corner frequency (about 12 dB per octave), and are forgiving if the volume is slightly off the target. In a car or truck, the cabin itself boosts low bass as the frequency drops, which suits the gradual sealed roll-off.
Ported boxes
A ported box has a vent, called a port, tuned to a frequency. Around that tuning frequency the air in the port moves with the cone and adds output, so the same amplifier power plays louder there. Ported boxes are larger, roll off faster below tuning (about 24 dB per octave), and need a subsonic filter set a little under the tuning frequency to protect the subwoofer.
Sealed
Ported
Box size
Smaller
Larger
Output per watt
Lower
Higher near tuning
Roll-off
Gentle
Steep below tuning
Sound
Tight, controlled
Louder, fuller low end
Fits well in
Trunks, behind seats, tight spaces
Trunks, SUV cargo areas
How to choose
Space is tight (behind or under a truck seat): sealed is usually the practical choice.
You want the most output from your amplifier and have room: ported.
Music with fast bass lines (rock, metal, country): many listeners prefer sealed.
Music with deep, sustained bass (hip-hop, EDM): ported often suits it.
Check the subwoofer first. Some drivers are designed for sealed boxes and some for ported. The spec sheet says which, and our spec sheet guide explains how to tell.
Undecided? Choose “Not sure” in the custom order form and we will recommend one for your sub and space. Or browse sealed and ported enclosures.
