subwoofers

A subwoofer is a loudspeaker dedicated to reproducing the lowest audible frequencies in an audio system. Subwoofers typically handle frequencies from around 20 Hz up to 80–120 Hz, depending on design, and are used to extend bass response beyond what smaller speakers can reproduce. They can be standalone units or built into full-range systems.

Most subwoofers are either active (powered) or passive. Active subwoofers include an internal amplifier and a built-in low-pass filter, often with adjustments for crossover frequency, volume, and phase. Passive subwoofers require an external amplifier and crossover. Enclosures are usually sealed (acoustic suspension) or ported (bass-reflex); some use passive radiators.

Placement and room interaction influence bass response. Subwoofers are often placed near walls or in corners to increase SPL, but placement can also cause boomy or uneven bass. Calibration features such as room EQ, phase alignment, and auto-setup help achieve smooth integration with main speakers.

Applications include home theater systems, two-channel stereo setups, professional sound reinforcement, and automotive audio. In cars, subwoofers are frequently mounted in enclosures in trunks or cargo areas and are typically driven by a car head unit or amplifier. Wireless subwoofers and compact models are common for small rooms.

In audio engineering, subwoofers are used to reproduce low-frequency content from music and film soundtracks. They are designed to complement full-range speakers by handling deep bass transients and high sustained bass power, contributing to overall system loudness and perceived impact without overloading smaller drivers.