File:Theater horn loudspeaker 1928.jpg
Jump to navigation
Jump to search
Size of this preview: 751 × 599 pixels. Other resolutions: 301 × 240 pixels | 602 × 480 pixels | 772 × 616 pixels.
Original file (772 × 616 pixels, file size: 136 KB, MIME type: image/jpeg)
Captions
Captions
Add a one-line explanation of what this file represents
Summary
[edit]
| Description |
English: Large horn loudspeaker from 1928 built for use in movie theaters and concert halls. Because early vacuum tube audio amplifiers couldn't produce much power, and horn loudspeakers can produce about 10 dB more sound power from an amplifier than a cone speaker, loudspeakers in theaters until WW2 were horn speakers. In order to reproduce bass frequencies adequately the horn had to be large, with a wide mouth and a sound path of 12 - 18 feet. This was a standard theater horn made by Bell Telephone Laboratories in New York for sound research. Scientist S. P. Grace holds a replica of Alexander Graham Bell's original telephone "loudspeaker" transmitter for comparison. |
| Date | |
| Source | Retrieved July 19, 2014 from G. C. B. Rowe, "The 'Electric Brain' and its language" in Radio News magazine, Experimenter Publishing Co., New York, Vol. 9, No. 12, June 1928, p. 1322 archived on American Radio History website |
| Author | G. C. B. Rowe |
| Permission (Reusing this file) |
This 1928 issue of Radio News magazine would have the copyright renewed in 1956. 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 1955, 1956 and 1957 show no renewal entries for Radio News. 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.
|
 |
File history
Click on a date/time to view the file as it appeared at that time.
| Date/Time | Thumbnail | Dimensions | User | Comment | |
|---|---|---|---|---|---|
| current | 13:00, 23 July 2014 | | 772 × 616 (136 KB) | Chetvorno (talk | contribs) | User created page with UploadWizard |
You cannot overwrite this file.
File usage on Commons
The following page uses this file:
File usage on other wikis
The following other wikis use this file:
- Usage on fr.wikipedia.org
- Usage on it.wikipedia.org
