Linear Noise-Attenuating Earphone.
Abstract
This document covers the technical details of work performed to improve the linearity and attenuation of the earphone and earcup respectively in Flying Type Helmet SPH-4. The results of the effort provide an immersible, salt resistant, rugged and low distortion earphone with a flat frequency response fitting an 8 dB response envelope when placed in the newly designed earcup which is lighter in weight but more rugged than the present standard SPH-4. The new ear-cushion utilizes a low permeability foam for improved attenuation in the low and mid-frequency range, which is covered with a urethane film for low temperature flexibility and body oil resistance. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 04, 1977
- Accession Number
- ADA048846
Entities
People
- R. Ramsey