Advent - SoundSpace Control Model 500 Signal processor

ADVENT 500 SOUND SPACE CONTROL
YEAR 1979
Exclusively on CATAWIKI
Rare and hard to find, this Advent Sound Space Control unit is in excellent condition
Vintage Advent 500 Sound Space Control reverb system with brochure. The world’s very first true surround sound system. This Advent unit, manufactured in 1979, takes a standard two-channel stereo signal, passes it to the two front speakers without modification, and delays the signal sent to the amplifier, thus controlling the two rear speakers to create a sense of space and reverberation. (It does not process 5.1 surround sound, but handles two front speakers and two rear speakers). Any audio history enthusiast will be won over by this Advent surround sound system, a real innovation. This unit is in excellent condition and delivers outstanding sound. On some recordings, the soundstage widens and deepens considerably; on others, the effect remains perfectly subtle. For a unit of this age, no distortion is to be lamented: the sound is clear and transparent. The rear channels have been tested and operate perfectly, with the same transparency as the front channels. All switches work perfectly and adjusting the reverberation and size index has indeed modified the sound. Please review the photos to better appreciate the condition of the unit.
In an open space, it requires sufficient power to showcase its flexibility; it offers a listening experience different from what is usually offered in an urban apartment. It digitally processes signals coming from a preamplifier, integrated with an amplifier or receiver, and adds time delays that are mixed and recycled to reproduce the space-specific acoustic difference of Advent’s Sound Space, making the sound richer, warmer and clearer. The acoustic absorption yields a rich, warm and clear acoustics. The sounds it creates—from standard stereo recordings or radio broadcasts—are intended to be transmitted to a second amplifier (which requires no adjustment) and heard through a second set of two loudspeakers or more placed in such a way as to create a three-dimensional experience that cannot be obtained with tone controls, reflective speakers, or conventional elements. It offers a three-dimensional experience never before achieved in home audio, thanks to a second amplifier (which requires no control) and a second pair of two loudspeakers or more, placed in the front and/or rear of a listening room.
In a home listening room it energizes the sound. With two simple basic controls, the Sound Space control lets you choose the size of the listening space you want to create and the desired level of reverberation. (A digital display “Size Index” lets you see as well as hear the size of the space you are creating.)
The SoundSpace control automatically places you in the theoretical “best seat” of any space you create, and selects a “scene depth” appropriate to the size of the space. A 32,000-hit computer — equivalent to more than 43,000 transistors. (In the era of vacuum tubes, its hardware would have filled an auditorium — and with very low noise and distortion (less than 0.1% at 80 dB) as well as an exceptional dynamic range and accuracy. With very low noise and distortion (less than 0.1%) at 80 dB, a dynamic range of 80 dB and substantial power.

ADVENT SOUND SPACE CONTROL MODEL 500
YEAR
1979

ADVENT 500 is a vintage digital delay and ambient reverberation processor from the 1970s/80s designed to simulate the rich acoustics of large listening spaces in a living room.

Overview and objective
• Ambience recovery: It acts as an early digital delay system.
• Acoustic illusion: It adds delayed reverberation to a second speaker system.
• Target sound: It transforms the standard room acoustics into a concert hall or larger space ambience.

Features and controls
• Inputs and outputs: Includes stereo inputs and a 4-channel output system (front and rear channels).
• Front outputs: Apply reverberation and spatial control.
• Rear outputs: Independent level, bass, treble and balance controls, and can operate normally or with reverberation.
• Digital display: Shows operational values (such as delay or setting modes).
• Physical switches: Includes a rear-channel bypass switch and variable reverberation buttons.

Configuration and connections
• Amplifier routing: Connects via stereo monitoring loops or standard tape loops, feeding multi-channel amplifiers.
• Speaker layout: Requires a pair of additional speakers for rear/ambient channels.
• Adjustment: Reverberation requires progressive adjustment to avoid audio distortion.

Active device technology
Memory 32,768 bits of MOS dynamic
RAM 4k RAM
Logic CMOS low power Schottky TTL
Analog High slew rate and BIFET integrated amplifiers
Frequency bandwidth all channels 20 - 20000 Hz
Distortion Less than 0.1% THD for a 1.5V - 1kHz output
The A/D conversion employed includes 8 bits of continuous digitization
Power requirements 220 VAC nominal 50/60 Hz 30 watts version available outside the US
Dimensions L 40 cm x H 8 cm x D 27 cm
Weight 5 kg