EFFECTS OF SPECTRUM SAMPLING ON SPEECH INTELLIGIBILITY
Abstract
A study was made of the effect on the intelligibility of phonetically balanced (PB) words of excising several narrow bands from a curtailed speech spectrum (1300 cycles). A spectrum composed of several discrete pass bands was compared to (1) the total curtailed spectrum, (2) the curtailed spectrum with one large segment removed from the end, and (3) the articulation predicted by the Articulation Index. 18 PB word lists uttered at three speech-to-noise ratios constituted the stimulus material presented to 36 subjects through a filter system with selected pass bands. Results indicate that at the higher speech-to-noise ratios, eliminating several narrow bands from the spectrum does not result in a corresponding reduction in intelligibility. When the speech is 35 dB above the noise, a reduction of 20% or more can be made in bandwidth without noticeable reduction in intelligibility. As the speech-to-noise ratio is decreased, the decrement in intelligibility becomes more nearly proportional to the decrease in bandwidth. A given bandwidth distributed over a spectrum area is more effective than an equivalent bandwidth massed in one part of the spectrum. Distributed sampling of the spectrum was found to be more effective than would be expected from Articulation Index computations.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 1969
- Accession Number
- AD0690261
Entities
People
- Anthony E. Castelnovo
Organizations
- United States Army Research Laboratory