| Main Title |
Environmental Effects on Microphones of Various Constructions. |
| Author |
Hruska, Gale R. ;
Magrab, Edward B. ;
Penzes., William B. ;
|
| CORP Author |
National Bureau of Standards, Washington, D.C.;Environmental Protection Agency, Washington, D.C. Office of Noise Abatement and Control. |
| Year Published |
1977 |
| Report Number |
NBS-2003110; |
| Stock Number |
PB-263 258 |
| Additional Subjects |
Microphones ;
Sensitivity ;
Calibrating ;
Pressure ;
Capacitors ;
Ceramics ;
Electrets ;
Temperature ;
Humidity ;
Environmental tests ;
Reprints
|
| Holdings |
| Library |
Call Number |
Additional Info |
Location |
Last
Modified |
Checkout
Status |
| NTIS |
PB-263 258 |
Some EPA libraries have a fiche copy filed under the call number shown. |
|
07/26/2022 |
|
| Collation |
5p |
| Abstract |
The pressure sensitivities of two 1/2-in. electret, two 1-in. ceramic, and two backvented 1-in. condenser microphones were measured for numerous combinations of temperature, percentage relative humidity, and frequency. The two condenser microphones were calibrated by the reciprocity technique at each combination of temperature, relative humidity, and frequency. The condenser microphones were then used as calibrated sources to determine the pressure sensitivities of the other microphones. Insert voltage techniques were used to eliminate the environmental effects on the electronics. It was found that the back-vented condenser microphones are insensitive to changes in relative humidity. At frequencies considerably below their resonance frequencies they exhibited only a very small change in sensitivity with temperature. At frequencies closer to the resonance frequency the temperature coefficient increases approximately fourfold. The temperature and humidity coefficient for the electret and ceramic microphones could not be determined due to the instability in their sensitivities which produced changes that were larger than those induced by the temperature and humidities. |
| Supplementary Notes |
Sponsored in part by Environmental Protection Agency, Washington, D.C. Office of Noise Abatement and Control. |
| Availability Notes |
Pub. in J. Acoust. Soc. Am., v61 n1 p206-210 Jan 77. |
| NTIS Title Notes |
Final rept.. |
| Title Annotations |
+++Reprint: Environmental Effects on Microphones of Various Constructions. |
| PUB Date Free Form |
Jan 77 |
| Category Codes |
20A; 68B; 46A; 86V |
| NTIS Prices |
Not available NTIS |
| Primary Description |
200/02 |
| Document Type |
NT |
| Cataloging Source |
NTIS/MT |
| Control Number |
323712130 |
| Origin |
NTIS |
| Type |
CAT |
