Bassrefleksikotelo

Bassrefleksikotelo, also known as a ported or vented enclosure, is a type of loudspeaker enclosure that uses a port or vent to improve the efficiency of the system, particularly at low frequencies. Unlike a sealed enclosure, which traps the air behind the driver, a bass reflex design allows the air that is pushed forward by the diaphragm to also move backward. This rear-emitted sound wave is strategically timed and phased by the port to reinforce the sound wave emitted from the front of the driver at a specific frequency.

The design of the port is crucial. Its diameter and length are calculated to create a Helmholtz resonator effect. At the resonant frequency of the port, the air within it moves with a large amplitude, acting like a second diaphragm. This resonance boosts the output of the woofer around that frequency, extending the bass response lower than a sealed box of the same volume or allowing for a smaller box for a given bass extension.

The main advantage of a bass reflex enclosure is its increased efficiency and deeper bass extension. However, this comes at the cost of potentially poorer transient response compared to sealed enclosures, as the port can introduce some coloration or "boominess" if not carefully designed and tuned. Below the tuning frequency, the port's output diminishes, and the driver can become less damped, leading to over-excursion risks if driven too hard. Bass reflex designs are very common in subwoofers and many consumer loudspeakers due to their ability to produce impactful low-frequency sound.