Advent Unit with Dolby Noise Reduction

Advent Unit with Dolby Noise Reduction

<< >>
Usage conditions apply
Description (Brief)
Ray Dolby’s 1965 invention of a system for reducing unwanted noise in magnetic tape recording significantly enhanced sound quality in consumer devices. His circuit design compressed and then expanded the electrical signal, a design he called a “sound compander” for which he received U.S. Patent 3,846,719. At first, Dolby’s compander was sold as an add-on component but by the early 1970s, it became an integral part of the equipment. This Advent model 201 cassette deck features a switch to activate Dolby’s system. The recorder also included a switch that allowed the use of chromium oxide tapes. The CrO2 tapes gave superior performance than ordinary ferrite oxide tapes but the sound properties could change over time. The switch helped the Dolby system compensate.
Object Name
tape recorder
magnetic recorder
date made
ca 1972
Advent Corporation
overall: 5 in x 13 7/8 in x 9 1/2 in; 12.7 cm x 35.2425 cm x 24.13 cm
ID Number
catalog number
accession number
Credit Line
from Dagmar Dolby
See more items in
Work and Industry: Electricity
Inventing in America
Exhibition Location
National Museum of American History
Data Source
National Museum of American History
Nominate this object for photography.   

Our collection database is a work in progress. We may update this record based on further research and review. Learn more about our approach to sharing our collection online.

If you would like to know how you can use content on this page, see the Smithsonian's Terms of Use. If you need to request an image for publication or other use, please visit Rights and Reproductions.


Add a comment about this object