Sealed Vs Ported Subwoofer Boxes

The most common and versatile type of enclosure is sealed. This style enclosure is ideal for any application where space is going to be an issue. In some cases a sealed recommendation for subwoofer box will be half of what the ported recommendation is. They also have the advantage over ported and band pass enclosures in terms of overall sound clarity. A sealed subwoofer box will deliver a tight, clean and accurate bass response and have a flat frequency response curve. In general a sealed box will be for listeners looking for sound quality driven system that is clean across the entire frequency band.

Next up are ported or vented enclosures, "ported" & "vented" are synonymous, it just means the enclosure has a hole in it to let air escape. You know that guy you can hear from 2 blocks away? Well he is likely running ported box. This style enclosure will likely be about twice the size of a similar sealed box since the airspace inside the chamber is much larger. Ported enclosures are tuned to a certain frequency range which is determined by the port length, width and diameter. The port can be in several configurations such as rounded or a slot which is narrower and taller. Each subwoofer will have a specific frequency they are designed to run at for maximum output. Depending on what you plan to use the enclosure for it can be tuned to various frequency ranges by modifying the port.

In general most competition SPL vehicles tune to high frequencies around 45Hz or higher. This setup would be designed for absolute maximum output but sacrificing a great deal of sound quality. A ported box tuned 25Hz will still allow your system to hit the ultra low bass notes while still keeping sealed like sound quality. The disadvantage is the enclosure will then have a fairly flat frequency range. And then the most common frequency range found usually in pre-built ported / vented enclosures is around 33 - 35Hz. At this frequency the enclosure will still deliver much more bass output than a sealed box but at the same type with still retain most of the sound quality. In other words you will get the best of both worlds with a ported box run at about 33Hz.

And last but not least are Bandpass enclosures. These are a hybrid box version and combine the features of a sealed and ported sub box into one enclosure. They are generally the hardest to build and design but offer some unique advantages. Bandpass enclosures are all about efficiency. How they work is a subwoofer or subwoofers in some cases are mounted inside a dual chambered box. One chamber is sealed and the other is ported / vented. The sound waves travel from the sealed subwoofer chamber though and out the port. This allows for a much deeper sounding bass and will be tuned to a narrow frequency band which creates a very aggressive sound. Not all subwoofers will work in bandpass enclosure so make sure you research or check the manual first.