Accession Number:

ADA801483

Title:

Design of an Automatic Octave Sound Analyzer and Recorder

Corporate Author:

HARVARD UNIV CAMBRIDGE MA CRUFT LAB

Report Date:

1942-11-21

Abstract:

An automatic octave sound apparatus is described which is suitable for analyzing and measuring sound in combat vehicles. An Ra-277 G sound frequency analyzer when used with a suitable graphic level recorder, permitted analysis of noise over a frequency range from 40 to 10,000 cycles per second by means of a 5-cycle wide or 200-cycle wide band pass filter. It was learned that airplane noise was produced by the propeller, by the engine exhaust, and by air leaks and aerodynamic flow. A complete system composed of a dynamic microphone, an octave band-pass filter set, a sound level meter, an automatic graphic level recorder, a battery power supply, and a hand-held remote control unit is described that determines either manually or automatically, sound levels in airplanes by octave bands.

Supplementary Note:

DOI: 10.21236/ADA801483

Pages:

0082

Identifiers:

Communities Of Interest:

Modernization Areas:

Distribution Statement:

Approved for public release; distribution is unlimited.

Contract Number:

OEMSR-658

File Size:

12.35MB