Bose 901 Active Equalizer

An active equalizer required for the Bose 901 Direct/Reflecting speaker system to achieve its intended frequency response.

Overview

The Bose 901 Active Equalizer was designed by Bose Corporation for the Bose 901 Direct/Reflecting speaker system, introduced in 1968. The speakers need active equalization to work as intended. The equalizer applies substantial boost below 100 Hz and above 3000 Hz to match the speakers' unique power response. Without it, the speakers don't perform to design.

This unit is made to work with the Bose 901 Series II, Series V, and Series VI Direct/Reflecting speaker systems. It is part of Bose's proprietary system, which stayed in production for over 50 years.

Design

The Bose 901 Active Equalizer applies significant frequency correction to the audio signal. It boosts output below 100 Hz and above 3000 Hz, which compensates for the acoustic characteristics of the 901 speakers and gives the balanced, spatial soundfield Bose designed them for.

Context

The Bose 901 Direct/Reflecting speaker system was introduced in 1968 and stayed in production for over 50 years. The 901 Active Equalizer is a required part of the system. It was not intended for standalone use or for use with other speakers. When properly set up, the combination produces a three-dimensional soundfield that fills the room.