Advent Model 500 (1979)

Not much is documented about the Advent Model 500. It was a signal processor called the "SoundSpace Control," built to create rear-channel effects from a stereo source. Nearly everything known about it comes from its listing in Audio (May 1979, p.70). The unit processed two independent rear channels. The front channels passed straight through as a bypass at unity gain. The specifications suggest it went in between the preamp and the power amplifier.

The rear-channel section had these measured characteristics:

Frequency Response: 20 Hz to 20 kHz
Distortion: Less than 0.1% at 1 kHz for 1.5 V output
Dynamic Range: 80 dB
Input Sensitivity: selectable 0.3, 1.0, or 3.0 V for rated output
Bass Control: Baxendall type, corner frequency varying from 95 to 200 Hz with rotation
Treble Feed Control: 6 dB boost to infinite cut above 6 kHz

The unit ran on 95-135 V AC, 50/60 Hz, and drew 30 watts. Dimensions are only partly recorded - width was 15¼ inches (40 cm). No further design details, production run or original price have surfaced. A later, unrelated Advent "500" showed up in the early 1990s as part of the New Vision Series loudspeaker line. It is a completely different product, and no specifications for it are documented here.