Spectral Unveils the SDR-4000SL Master CD Processor
Spectral Audio , the northern California company whose director of engineering is Prof. Keith O. Johnson, gave the first public preview of its SDR-4000SL Master CD Processor on September 24, at Music Lovers Audio, in Berkeley. Introduced by Johnson and Spectral founder Richard (Rick) Fryer, the $19,000 Spectral Digital Resolution (SDR) model sounded sensational playing 16-bit/44.1kHz, HDCD-encoded files Johnson had made for Reference Recordings, through a system that included Spectral's DMC-30SS preamplifier and monoblock amplifiers, Wilson Audio MAXX 3 speakers, Spectral Ultralink II speaker cables, the MIT Z Duplex conditioner, Synergistic Research's controversial ART system, and other room treatments.