File:Racon theater horn loudspeaker.jpg
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Summary
| Description |
English: A large horn loudspeaker made by Racon Electric Co., New York in the 1920s for use in movie theaters and auditorium sound systems, from a 1928 magazine advertisement. Horn loudspeakers were used almost exclusively for large area sound systems into the 1930s since high power cone loudspeakers were not developed and horns could produce 10 times the sound power of a cone for a given amplifier output. Racon specialized in these large theater horns. The speaker consists of a coiled exponentially widening sound tube driven at its narrow end by a compression driver consisting of a small metal diaphragm vibrated by a powerful electromagnet. Since horn loudspeakers had a lower cutoff frequency, large horns with long air columns and wide mouths like this were required to reproduce bass frequencies accurately. It was made of fabric impregnated with a cement hardener, which did not resonate with sound waves as a metal horn would. Alterations to image: cropped out surrounding advertising copy, which said in part: Racon Exponential Air-Column Horns are made in all shapes and sizes up to 6 feet square for Theatres and Auditoriums. Maximum Air Column in minimum space. |
| Date | |
| Source | Retrieved January 25, 2015 from Popular Radio magazine, Popular Radio, Inc., New York, Vol. 8, No. 5, May 1928, p. 357, on http://www.americanradiohistory.com |
| Author | Unknown author |
| Permission (Reusing this file) |
This image is from an advertisement for Racon Electric Co. without a copyright notice published in a 1928 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. |
Licensing
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This work is in the public domain in the United States because it was published in the United States between 1929 and 1977, inclusive, without a copyright notice. For further explanation, see Commons:Hirtle chart as well as a detailed definition of "publication" for public art. 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 (50 p.m.a.), Mainland China (50 p.m.a., not Hong Kong or Macao), Germany (70 p.m.a.), Mexico (100 p.m.a.), Switzerland (70 p.m.a.), and other countries with individual treaties.
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File history
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| Date/Time | Thumbnail | Dimensions | User | Comment | |
|---|---|---|---|---|---|
| current | 03:20, 26 January 2015 | | 725 × 914 (96 KB) | Chetvorno | User created page with UploadWizard |
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