Design and Circuitry of Stereo Integrated Amplifier, including Digital Room Correction and Dual Subwwofer Bass Management David A. Rich, Ph.D.June 1, 2012 In depth analysis and discussion of the design and circuitry of a stereo integrated amplifier, including digital room correction and dual subwoofer bass management: evaluating the HK 990 Stereo Integrated Amplifier. Technical Reviews