Physical Sound Parameters Research Articles

Abnormal auditory pattern perception in schizophrenia

Mismatch negativity (MMN) in response to deviation from physical sound parameters (e.g., pitch, duration) is reduced in individuals with long-term schizophrenia (Sz), suggesting deficits in deviance detection. However, MMN can appear at several time intervals as part of deviance detection. Understanding which part of the processing stream is abnormal in Sz is crucial for understanding MMN pathophysiology. We measured MMN to complex pattern deviants, which have been shown to produce multiple MMNs in healthy controls (HC). Both simple and complex MMNs were recorded from 27 Sz and 27 matched HC. For simple MMN, pitch- and duration-deviants were presented among frequent standard tones. For complex MMN, patterns of five single tones were repeatedly presented, with the occasional deviant group of tones containing an extra sixth tone. Sz showed smaller pitch MMN (p=0.009, ~110ms) and duration MMN (p=0.030, ~170ms) than healthy controls. For complex MMN, there were two deviance-related negativities. The first (~150ms) was not significantly different between HC and SZ. The second was significantly reduced in Sz (p=0.011, ~400ms). The topography of the late complex MMN was consistent with generators in anterior temporal cortex. Worse late MMN in Sz was associated with increased emotional withdrawal, poor attention, lack of spontaneity/conversation, and increased preoccupation. Late MMN blunting in schizophrenia suggests a deficit in later stages of deviance processing. Correlations with negative symptoms measures are preliminary, but suggest that abnormal complex auditory perceptual processes may compound higher-order cognitive and social deficits in the disorder.

Karl Kryter—Soundscape pioneer

Karl Kryter was a pioneer in the soundscape analysis field, even before the field had a name. Defined as the combination of the study of physical sound parameters with the perception of sound by listeners in an environmental context, soundscape analyses were conducted and reported by Kryter well before the term “Soundscape” was coined by R. Murray Schafer in 1977. These included several studies of community reactions to noise from subsonic aircraft while Kryter was with Bolt, Beranek and Newman in the 1950’s. Those studies were followed by laboratory and field tests of listener reactions to aircraft noise in the 1960’s. Kryter compiled and compared similar attitudinal and perceptional studies of transportation noise by other researchers in his 1970 book “The Effects of Noise on Man”. This compilation has proven to be comprehensive and enduring in its presentation of noise perception data. Kryter’s insights from those early studies provide valuable guidance to current and future soundscape researchers and soundscape design practitioners.

신체 동작을 모사한 직물마찰음 발생장치의 개발 및 이를 이용한 직물 마찰음 평가

To investigate the sound generated by fabric friction, which simulates real wear conditions, a 'fabric friction sound generator', which simulates body movement was developed. Fabric sounds from three specimens were generated by the fabric sound simulator and recorded using high performance microphones. Physical sound parameters such as sound pressure level (SPL), level range (<TEX>${\Delta}L$</TEX>), and frequency difference (<TEX>${\Delta}f$</TEX>) were calculated for the fabrics. All the physical parameters (SPL, <TEX>${\Delta}L$</TEX>, and <TEX>${\Delta}f$</TEX>) of fabric sounds generated by the fourth-generation apparatus had lower values compared to the values obtained with the third-generation apparatus. Unlike the third-generation system, which generates fabric sounds by reciprocating friction, the fourth-generation system was designed with silicon-based arm-and-leg shaped abraders so that the levels of noise and fabric sounds generated were lower at all speeds.

Sound characteristics according to cross-sectional shapes of fibers

In order to investigate the effects of cross-sectional shapes on the sound characteristics of polyester fibers, 10 specimens were woven into a twill structure made of round, hollow, triangular, u-shape, cruciform, and composite cross-sectional (▴/▴, ()/▴,Y y) fibers. Their rustling sounds were recorded, and their sound spectra were obtained from FFT analysis. Physical sound parameters (LPT, ΔL, Δf) and Zwicker’s psychoacoustic parameters of the loudness(Z), sharpness(Z), roughness(Z), and fluctuation strength(Z) were calculated from the sound spectra. According to noncircular cross-section fibers, the hollow shaped fiber had the highest value of LPT, ΔL, loudness(Z), and fluctuation strength(Z). The triangular shaped fiber had a lower value of LPT, ΔL, loudness(Z), and roughness(Z) than those of the round shaped fiber. Among composite cross-section fibers, C1 (▴/▴) and C3 (Y y) had higher values of LPT, ΔL, Δf, and loudness(Z) but C2 (()/▴) had lower values. Also the LPT, ΔL, sharpness(Z), and roughness(Z) values of different denier were similar to each other, but the Δf and loudness(Z) values increased as the denier increased.

Characteristics of Rustling Sounds Created by the Structure of Polyester Warp Knitted Fabrics

The rustling sounds of seven samples are recorded in order to determine the sound characteristics of polyester warp knitted fabrics according to construction type. Physical sound parameters (LPT, ΔL, Δf, ARC) and Zwicker's psychoacoustic parameters of loudness ( z), sharpness ( z), roughness ( z ), and fluctuation strength ( z) are calculated from sound spectra obtained from FIT analysis. In addition, the KES-FB system is used to measure the mechanical properties. The sharkskin stitch fabrics have the highest LPT, Δf, ARC, loudness ( z), and fluctuation strength ( z) values, followed by the double denbigh and reverse locknit stitch fabrics. The open lap is louder, sharper, and has a larger fluctuation strength than the closed lap in stitch formation. LPT, Δf, ARC, loudness ( z), roughness ( z), and fluctuation strength ( z) of the parallel direction have higher values than those in the counter direction in lapping formation between the back and front bar. Changes in the mutual guide bar movement from counter to parallel are more effective at making a warp knitted fabric's sound louder than the lapping form change from closed to open lap.

Effects of Basic Weave Differences in Silk Fabric and Yarn Type Variations in Satin Weave on Sound Parameters

In order to investigate the effects of basic weaves and yarn types on the sound characteristics of silk fabrics, seven samples are woven to the same density, their rustling sounds are recorded, and their sound spectra are obtained from FIT analysis. Physical sound parameters ( LPT, Δ L, Δf, ARC) and Zwicker's psychoacoustic parameters of loudness( z), sharpness( z), roughness( z), and fluctuation strength( z) are calculated from the sound spectra. The basic weave types change the amplitudes of the sound spectra, while the weft yarn type in the satin weave determines the shapes of the spectra. Loud ness( z) varies with weave type. Of all the silk specimens, twill fabric has the highest loudness( z) due to its high LPT and ARC, but satin fabric with filament yarn has the lowest loudness( z) due to low LPT and ARC. In basic weaves, loudness( z) varies, but sharpness( z), roughness( z), and fluctuation strength(z) are similar. As for yarn types, loudness(z) is increased by noil yarn, sharpness(z) by spun yarn, and roughness(z) by highly twisted yarn, compared with filament yarns.

Hair Cell Damage in the Inner Ear of the Guinea Pig Due to Noise in a Workshop

Guinea pigs were exposed to noise in various workshops at a shipyard. The equivalent sound level ranged from 87 to 90 dB(A) and the exposure time was 30 days of 8 hours. The numbers of lost outer hair cells were greater than in control animals, thus establishing a relation between the number of lost hair cells and the total noise dose. A comparison between the results obtained here and results obtained in laboratory experiments shows that although many physical sound parameters may be identical, the effect on the hair cells can be quite different. In particular, the total noise dose is not a parameter which can be directly related to hair cell loss. The most probable explanation for the difference in damage between the laboratory and workshop animals seems to be the rest periods of 16 hours between each of the 8-hour exposure periods.