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, built in 1979, takes a standard two-channel stereo signal, passes it to the two front speakers without alteration, and delays the signal sent to the amplifier, thereby controlling the two rear speakers to create a sense of space and reverb. (It does not process 5.1 surround sound, but handles two front speakers and two rear speakers). Any audio history enthusiast will be captivated by this Advent surround sound system, a genuine innovation. This unit is in excellent condition and delivers exceptional sound. On some recordings, the soundstage widens and deepens considerably; on others, the effect remains perfectly discreet. For a device of this age, no distortion is to be noted: 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 function perfectly, and adjusting the reverb and size index has indeed altered the sound. Please see the photos to better appreciate the unit’s condition.
In an open space, it requires enough power to showcase its flexibility; it offers a listening experience different from the usual urban apartment setup. It digitally processes signals coming from a preamplifier, integrated into an amplifier or receiver, and adds time delays that are mixed and recycled to reproduce the acoustic difference specific to Advent’s Sound Space, making the sound richer, warmer, and clearer. The acoustic absorption produces a rich, warm, and clear ambience. The sounds it creates—from standard stereo recordings or radio broadcasts—are intended to be transmitted to a second amplifier (requiring no adjustment) and heard through a second set of two speakers or more placed to create a three-dimensional experience that cannot be achieved 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 (requiring no controls) and a second set of two or more speakers placed in front of and/or behind the 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 amount of reverberation. (A digital display “Size Index” lets you see and hear the size of the space you are creating.)
The SoundSpace control automatically places you in the theoretical “best seat” in any space you create, and selects a “stage 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 — with very low noise and distortion (less than 0.1% at 80 dB) and 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 considerable power.

ADVENT SOUND SPACE CONTROL MODEL 500
YEAR 1979

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

Overview and objective
• Ambience retrieval: It acts as an early digital delay system.
• Acoustic illusion: It adds delayed reverberation to a second set of speakers.
• Target sound: It transforms a room’s standard acoustics into a concert hall or larger venue ambience.

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

Configuration and connections
• Amplifier routing: Connects via stereo monitor loops or standard tape loops, feeding multichannel amplifiers.
• Speaker layout: Requires a pair of additional speakers for the rear/ambient channels.
• Adjustment: Reverb requires gradual 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 BI-FET integrated amplifiers
Frequency bandwidth for all channels 20 - 20000 Hz
Distortion Less than 0.1% THD for a 1.5V - 1kHz output
The A/D conversion used 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 P 27 cm
Weight 5 Kg