Image: Jensen ad for Alnico 5 speakers

Description: Advertisement by Jensen Radio Manufacturing Co. in 1945 for speakers made with Alnico 5 magnets, a new type of permanent magnet which had been developed during World War 2. As illustrated in the ad Alnico 5, the most powerful magnet yet developed, allowed a dramatic reduction in the size of speaker magnets from 98 ounces in 1930 to 4.65 oz. Alnico remained the most powerful type of permanent magnet until rare earth magnets were developed in the 1980s.
Title: Jensen ad for Alnico 5 speakers
Credit: Retrieved June 12, 2014 from Radio News magazine, Ziff-Davis Publishing Co., New York, Vol. 33, No. 4, April 1945, p. 7 on American Radio History site
Author: Unknown
Permission: This image is from an advertisement for Jensen Co. without a copyright notice published in a 1945 magazine. In the United States, advertisements published in collective works (magazines and newspapers) are not covered by the copyright notice for the entire collective work. (See U.S. Copyright Office Circular 3, "Copyright Notice", page 3, "Contributions to Collective Works".) Since the advertisement was published before 1978 without a copyright notice, it falls into the public domain.
Usage Terms: Public domain
License: Public domain
Attribution Required?: No