File:Two double button carbon microphones.jpg
Jump to navigation
Jump to search
No higher resolution available.
Two_double_button_carbon_microphones.jpg (245 × 225 pixels, file size: 16 KB, MIME type: image/jpeg)
Captions
Captions
Add a one-line explanation of what this file represents
Summary
[edit]
| Description |
English: Two Western Electric double button carbon microphones from 1938. Developed by Western Electric in 1921, the double button carbon microphone was a higher fidelity version of the ordinary carbon microphone and was widely used for public address systems, recording, and radio broadcasting during the 1920s and 30s. They are now often referred to as "ring and spring" microphones due to the spring suspension system, which isolated the sensor unit acoustically from its support stand. |
| Date | |
| Source | Retrieved July 2, 2014 from Gleason L. Archer (1938) Hostory of Radio to 1926, American Historical Society Inc., printed by Stratford Press Inc., New York, facing p. 198 on American Radio History website |
| Author | Gleason L. Archer |
| Permission (Reusing this file) |
This book, published in 1938 would have the copyright renewed in 1966. Online page scans of the Catalog of Copyright Entries, published by the US Copyright Office can be found here. [1] Search of the Renewals for Periodicals for 1965, 1966 and 1969 show no renewal entries for History of Radio or "Gleason Archer". Therefore the copyright was not renewed and it is in the public domain. |
Licensing
[edit]
|
This work is in the public domain because it was published in the United States between 1929 and 1963, and although there may or may not have been a copyright notice, the copyright was not renewed. For further explanation, see Commons:Hirtle chart and the copyright renewal logs. Note that it may still be copyrighted in jurisdictions that do not apply the rule of the shorter term for US works (depending on the date of the author's death), such as Canada (70 years p.m.a.), Mainland China (50 years p.m.a., not Hong Kong or Macao), Germany (70 years p.m.a.), Mexico (100 years p.m.a.), Switzerland (70 years p.m.a.), and other countries with individual treaties.
|
 |
File history
Click on a date/time to view the file as it appeared at that time.
| Date/Time | Thumbnail | Dimensions | User | Comment | |
|---|---|---|---|---|---|
| current | 08:42, 7 July 2014 | | 245 × 225 (16 KB) | Chetvorno (talk | contribs) | User created page with UploadWizard |
You cannot overwrite this file.
File usage on Commons
There are no pages that use this file.
