collaborated with Telarc for several years, producing legendary symphonic recordings; the earliest ones are chronicled in Renner. The care with which Telarc selected and used its microphones and audio console, combined with the Soundstream recorder, created a gold standard for audiophile recording. Telarc has re-released many of its original Soundstream recordings in SACD format. Soundstream recordings made before the advent of the CD were released as high-quality vinyl LP albums. Despite analog playback, many of these releases were sufficiently impressive to gain an early acceptance for digital audio. The recording industry's transition to digital was further facilitated by the many demonstrations given by Dr. Stockham, whose articulate explanations of digital audio theory and practice were renowned. In 1980, Digital Recording Corporation (DRC) acquired Soundstream. DRC attempted to develop a home digital player that would use a photographically reproducible optical card as opposed to the mechanically pressed CD. This effort was eclipsed by the rise of the CD, leading to the company's demise in 1985. Technology The company developed its four-channel, 16 bit, 50 ksps recorder in 1977. The Soundstream Digital Tape Recorder (DTR) consisted of a modified Honeywell 5600E instrumentation transport and analog and digital circuitry designed and built by Soundstream. There were 2 series of DTR's built. the first series (SN 1–4) was produced from ~1977 to 1979 and the second series (SN 5- 13) produced ~1980 to 1981. While being tape format compatible and looking nearly identical from the outside, the later series are easily identified by the second set of tape transport control buttons. Some Internal cards are not 100% compatible between the 2 series. Digital Tape Recorder The Digital Tape Recorder was a portable four-channel digital audio processor containing the analog to digital converters, tape-data recovery and clock generation circuits, and the digital to analog converters. External hardware (tape drive, editing system, and digital delay unit) connected to the DTR through connectors on the back panel. The unit measured 20"x18"x10" and weighed 67 pounds. Analog signals entered the DTR through standard XLR connectors at the rear of the unit. There, a differential input amplifier routed the signal through the front panel attenuation fader to the input low-pass (anti-alias) filter. The antialias filter (custom made by TTE Filters) is a passive 11 pole elliptical function filter with a -3 dB point of 22.5 kHz. The analog signal path from input XLR connector to the A/D converter is