Ported VS Sealed enclosures

Ported VS sealed enclosures; I often get asked which I recommend? There are characteristics of each that make them both suitable, sometimes for the same situation. Let me give a breakdown of a few things about each to explain.

Sealed Enclosures;
Sealed enclosures first off are as much as half the size of a ported enclosure, but that varies according to not only the speaker, but the tuning of the box. A larger sealed box will have a deeper resonance which means it will produce deeper bass than the same speaker in a smaller box, but a large box has less power handling ability. The smaller box will also have less output, but a higher Q which is the tendency for the speaker to resonate or vibrate more at its resonant frequency. The resonant frequency is the frequency at which all objects are most sensitive to vibration. A tuning fork is a good example of something that has a very high "Q". If your goal was to build a SPL (sound pressure level) vehicle your best bet is usually small sealed boxes. The speaker will handle lots of power, and have a high tendency to vibrate in a narrow band. If you have ever actually "listened" to an SPL system you know they sound pretty nasty, no deep bass at all.

Ported Enclosures;
Ported enclosures in the past were thought of as "boomy", but it is possible to design one that has a smooth response, in fact some of the best studio monitors which are designed for a true and smooth linear response are ported. The amount of gain that the port produces can be adjusted up to 24 DB, although that much gain would be very boomy, not to mention abusive for the woofer. One of the problems of a ported enclosure is the tendency of the speaker to vibrate wildly one octave below the tuned frequency which is usually a little below the resonant frequency of the speaker. For that reason, all ported speakers should be driven with an amplifier that has a sub-sonic filter that cuts out these frequencies which are too low to be heard anyway and just waste amplifier power. Ported enclosures are great to give a little more bass in medium to lower powered systems, assuming it’s a good amplifier; ported speaker’s need the control a quality amp has. Besides the much larger size of a ported box compared to a sealed box, there is the tendency for more blown speakers. That down side is aggravated by the fact that most people who want a ported enclosure are more likely to abuse their equipment. If your reason for wanting a port is strictly lots of bass, you are better off getting a larger amp and a better woofer in a sealed box that is slightly on the large side.

So back to the question, which do I recommend? I make recommendations based on these questions and situations;
What kind of enclosure is the woofer you want to use suitable for; not all woofers work their best in both sealed and ported boxes.
What kind of music do you listen to; rap or hip-hop or anything with a generated tone or drum machine producing bass? A ported enclosure might be the best choice for you as long as you’re willing to give up the extra trunk space and are going to use an amplifier that has a sub-sonic filter. But if you listen to this type of music but don’t need or want bone shaking bass and prefer tight punchy but deep bass, a sealed box designed slightly on the large size may suit you better.
For any music with bass that is not electronically recorded like most country, rock, alternative rock, or jazz, a sealed box would be a better choice, its size determined by the speaker choice and the amount of power and deep rumble you want.
Is your goal a serious street pounder or all out SPL vehicle? And then there’s the bigger question; what size woofers to use…….
Dan

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