Selecting the right sub enclosure

So you want bass in your sound equation? Now what type of bass? Heavy deep loud bass, or precise sharp bass? This is the question you really have to ask yourself when planning the bass in your sound system.

There are four main types of bass enclosures, namely sealed (the correct term is actually acoustic suspension), vented (better known as bass reflex), band-pass (4th order and 6th order) and Isobaric enclosures. All these types have certain specific gains and losses.

Physics plays a lot in your decision making here. Deep bass sound waves have an extremely long wavelength, between 6-12 metres, which is a slow difficult wave to transmit through the air, but this isn’t that difficult in very small areas like a car’s interior, which acts a sort of a gain in your subs performance.

So let’s take a look at what each type enclosure gives you.

Sealed
These enclosure produce night tight upper bass and excellent sub sonic representation (those frequencies less than 20Hz). This type of enclosure is usually your best all-rounders with good power handling. Easy and simple to design and build.

Vented
30-60Hz range performers. These enclosures have a certain “tuning” frequency, above which the power handling is great, but pathetic below that. A little trickier to design and build.

Band-pass
The most of efficient of the 3 main types of enclosure. It suffers slightly of a long group delay (slow response), can really suffer in the power-handling department if badly designed and has a high-frequency roll-off effect that makes it difficult to match with mid-bass setups. Designing and building these enclosures is very tricky.

Isobaric
Not really and enclosure type, but have the added benefits of adding very compact enclosures with two subs, which has no performance losses, but could shorten your amp’s lifespan.