THE JOURNAL OF THE ACOUSTICAL SOCIETY OF JAPAN

Experiments on the perceived noisiness of repetitive impulses.

Tetsumi Sato, Kiyoto Izumi

Article type: Article
1982 Volume 38 Issue 10 Pages 609-618
Published: October 01, 1982
Released on J-STAGE: June 02, 2017

DOIhttps://doi.org/10.20697/jasj.38.10_609

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Five series of psycho-acoustical experiments are performed in a semi-anechoic chamber. Five to eleven subjects judge the perceived noisiness and the loudness of repetitive impulses by means of the comparison with those of continuous sounds by the constant method or the adjustment method. The principal findings are as follows:1)The judged noisiness of repetitive impulses are prominent than the judged loundness. This trend is clear at lower sound pressure levels and with respect to "real life" sounds. 2)To the noisiness ratings of repetitive impulses, L_<eq> is not quite satisfactory. Some corrections on the spectral characteristics such as PNL and on the temporal characteristics are required. 3)The perceived noisiness of repetitive impulses consists of the energy effect and the impulsive effect. For the abatement of the impulsive effect, the repetition rate, the decay time and the background-to-burst level are important factors, while the rise time is of little importance.

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Two period M-sequence method for observation of underwater ultrasound propagation.

Shigeo Ohtsuki, Motoyoshi Okujima

Article type: Article
1982 Volume 38 Issue 10 Pages 619-623
Published: October 01, 1982
Released on J-STAGE: June 02, 2017

DOIhttps://doi.org/10.20697/jasj.38.10_619

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Underwater ultrasound traveled long range carries various information such as sea flow. When pulsive ultrasound is emitted, ambient pulsive noises make it difficult to detect the ultrasound traveled long range, because it is faint. In order to overcome this difficulty, two period M-sequence method is devised. An M-sequence signal trancated to the duration of two periods is transmitted and received. The received signal is processed into pulsive signals equivalent to the signals that are observed when a pulsive ultrasound is transmitted. This method enables to transmit high power signal with relative small amplitude. An ultrasound propagation test was performed in shallowwater with the system based on this method. Propagated signals up to the range of3, 400m were detected successfully.

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Graphite/polyvinyl chloride composite for loudspeaker diaphragm.

Tsunehiro Tsukagoshi, Shinichi Yokozeki, Sumio Hagiwara, Yasuyuki Arai

Article type: Article
1982 Volume 38 Issue 10 Pages 624-632
Published: October 01, 1982
Released on J-STAGE: June 02, 2017

DOIhttps://doi.org/10.20697/jasj.38.10_624

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Graphite/Polymer composite named PG is studied for loudspeaker diaphragm material. Polyvinyl chloride(PVC)and graphite powder with flake shape(the mean grain size5μm)are mainly used as raw materials for PG. Increment of the graphite contents results in a high Young's modulus and a high breaking strength provided with an almost equal internal loss. However, the maximum graphite content is found to be 65wt%. In this case following physical properties are obtained:the sound velocity of about6×10^3m/sec, which is20% faster than that of aluminum or titanium, and tanδ of about 0. 02. This latter value can be further increased up to 0. 045by adding 30wt% polyvinylidene chloride into the PVC. The temperature and frequency dependences of Young's modulus and tanδ of the PG are small up to40℃. The heat deformation temperature(HDT)of the PG cone-type diaphragm with 45mm diameter and 0. 07mm thickness is about 70℃. By replacing usaual PVC with post chlorinated PVC, the HDT can be raised about 100℃. Examining the orientation of the graphite flakes with an X-ray diffractometer, it is proved that the high Young's modulus in the PG sheet is attributed by highly oriented graphite flakes. A 12cm shallow type cone loudspeaker using the PG diaphragm(88mm diameter, 8mm depth)has a smooth frequency response up to 20kHz and has very low harmonic distortion cahracteristics.

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Quantitative analysis of the perceptual significance of the harmonic components in synthetic sounds with harmonic strusture.

Riichiro Mizoguchi, Osamu Kakusho, Nobuhiro Suzuki, Shizuo Nishiyama

Article type: Article
1982 Volume 38 Issue 10 Pages 633-642
Published: October 01, 1982
Released on J-STAGE: June 02, 2017

DOIhttps://doi.org/10.20697/jasj.38.10_633

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In speech research, it is well-known that formant frequency is one of the most dominant factors in auditory perception of speech. The main objective of this paper is to calculate the perceptual significance(weight coefficient)of the harmonic components of synthetic sounds with harmonic structure and to reveal the quantitative relation between the weight coefficients of different phonemes. Our method is based on the least-sequares optimization of the correspondence between the psychological space and physical space of sample sounds, and is composed of the following three steps:1)listening test, 2)metricalization of the psychological space, 3)solving the problem of the correspondence between the psychological space and physical space. New original ideas are employed in the operation at every step. The weight coeficients of five vowel-like sounds/a/, /i/, /u/, /e/, /o/and an unusual sound like/ae/are obtained according to the proposed method, and their relation and difference are discussed quantitatively.

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A practical prediction method of L_<Aeq> due to road traffic noise.

Teruo Iwase, Hideki Tachibana, Kiyoteru Ishii

Article type: Article
1982 Volume 38 Issue 10 Pages 643-648
Published: October 01, 1982
Released on J-STAGE: June 02, 2017

DOIhttps://doi.org/10.20697/jasj.38.10_643

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The development of the digital compact cassette systems.

Masami Yamazaki

Article type: Article
1982 Volume 38 Issue 10 Pages 649-656
Published: October 01, 1982
Released on J-STAGE: June 02, 2017

DOIhttps://doi.org/10.20697/jasj.38.10_649

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Sonic diagnosis of cerebrovascular disorders.

Yukio Kosugi, Jun Ikebe, Kintomo Takakura

Article type: Article
1982 Volume 38 Issue 10 Pages 657-662
Published: October 01, 1982
Released on J-STAGE: June 02, 2017

DOIhttps://doi.org/10.20697/jasj.38.10_657

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Recent topics of speech analysis and synthesis technology.

Kazuo Nakata

Article type: Article
1982 Volume 38 Issue 10 Pages 663-668
Published: October 01, 1982
Released on J-STAGE: June 02, 2017

DOIhttps://doi.org/10.20697/jasj.38.10_663

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Report on the XVI International Congress of Audiology(Helsinki,May 23〜27,1982).

Satoshi Imaizumi

Article type: Article
1982 Volume 38 Issue 10 Pages 669-671
Published: October 01, 1982
Released on J-STAGE: June 02, 2017

DOIhttps://doi.org/10.20697/jasj.38.10_669

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Latin American Acoustics Seminar,22nd March〜10th April,at La Falda,Cordoba,Argentina.

Zyun-iti Maekawa

Article type: Article
1982 Volume 38 Issue 10 Pages 672-673
Published: October 01, 1982
Released on J-STAGE: June 02, 2017

DOIhttps://doi.org/10.20697/jasj.38.10_672

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