A lip microphone that eliminates background noise

Title (Dublin Core): A lip microphone that eliminates background noise
Subject (Dublin Core): en Technology; en Communication
Article Title and/or Image Caption (Dublin Core): Caption: A lip microphone that eliminates background noise has been invented for the Army and has many possibilities for peacetime use.
extracted text (Extract Text): A LIP MICROPHONE that eliminates background
noise has been invented for the Army and has many
possibilities for peacetime use. The mike has two holes |
—one against the lips through which the voice enters
to strike one side of the diaphragm, and the other on
the opposite side. Outside noises, being farther away,
enter both holes with equal force, strike the diaphragm
from both sides, and neutralize themselves. |
Language (Dublin Core): eng
Temporal Coverage (Dublin Core): [–][+]World War II
Date Issued (Dublin Core): 1944-04
Is Part Of (Dublin Core): Popular Science Monthly, v. 144, n. 4, 1944
pages (Bibliographic Ontology): 189
Rights (Dublin Core): Public Domain (Google digitized)
Source (Dublin Core): Google Books
Archived by (Dublin Core): Lorenzo Chinellato; Marco Bortolami (editor)