bassreflexkast

A bassreflexkast, also known as a ported enclosure or vented box, is a type of loudspeaker enclosure that uses a port or vent to improve the low-frequency reproduction of a woofer. This port is typically a tube or opening in the enclosure, and its size and length are carefully calculated to resonate with the air inside the box at a specific frequency.

The principle behind a bassreflexkast is to use the sound waves produced by the back of the woofer cone. In a sealed enclosure, these waves are trapped and absorbed, which can lead to a less efficient and sometimes "muddier" bass response. In a bassreflex design, the port is tuned so that the sound from the rear of the cone emerges in phase with the sound from the front of the cone at the tuning frequency.

This phase alignment results in a reinforcement of the bass output around the tuning frequency, which is typically lower than what the woofer could achieve in a sealed enclosure of the same size. This can lead to a subjectively deeper and more impactful bass. Additionally, the port can help to reduce the excursion (movement) of the woofer cone below the tuning frequency, which can improve power handling and reduce distortion.

However, bassreflexkasten are not without their drawbacks. They are generally larger than sealed enclosures for a given driver. Also, the bass response can fall off sharply below the tuning frequency, and the woofer can be easily overdriven below this point, leading to damage if not properly protected. The design requires precise tuning, and incorrect port dimensions can result in poor sound quality, such as a boomy or unarticulated bass.