Woofer or subwoofer are woofers; i.e. speaker systems for the reproduction of low tones and bass. These are loudspeakers and systems whose frequency range is below 100 Hz. At these frequencies, the human ear is no longer sensitive to direction. As a result, subwoofers can be operated independently without a special location within a sound environment.
Subwoofers are bass reflex boxes, often designed as bandpass boxes, which work with self-resonances and are equipped with Helmholtz resonators. They are characterized by powerful low-frequency reproduction that enriches the overall sound image. They are driven by their own power amplifiers with appropriate crossovers, respectively, which are located in the subwoofer cabinet or operate as separate amplifiers. Subwoofers are controlled via the LFE (Low Frequency Effect) channel or their own amplifier output and can be adjusted in frequency and level.
Such woofer systems are used in sound reinforcement systems, cinemas, home theaters, car acoustics, and high-quality audio systems such as Dolby Surround and Dolby Digital.