Basreflexen

Basreflexen is a term used in loudspeaker design to describe a vented or ported enclosure that uses a tuned port to extend the low‑frequency response. It is also known as a bass-reflex or vented-box design. The enclosure houses a loudspeaker driver and a port or tube that connects the cabinet interior to the outside air.

How it works: In a basreflex design, part of the energy from the rear side of the driver is allowed to escape through the port. The port is tuned to a specific frequency, determined by the cabinet volume, port length and diameter, and sometimes end corrections. At the tuning frequency, the port resonates and adds energy to the forward radiation, boosting bass output. Below the tuning frequency, the enclosure and port help extend bass efficiency without requiring an excessively large box. Above the tuning point, the response typically drops due to the altered phase relationships between front and rear radiations.

Design considerations: The key parameters are the enclosure volume (V), the port cross‑sectional area (A) and length (L), and whether the port is front‑ or rear‑mounted. Designers aim for a target tuning frequency that balances bass extension with box size and with acceptable smoothness of the response. Port design must minimize noise from air turbulence (port chuffing) and avoid unwanted resonances or cavity effects. The choice between basreflex and other enclosure types depends on budget, size, and desired sound character.

Variants and use: Basreflex enclosures are common in home hi‑fi speakers and many commercial designs due to their efficiency and strong bass for compact boxes. They contrast with sealed (acoustic suspension) designs and with alternatives like passive radiators, which achieve similar goals with different trade‑offs.