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Standard

NS-EN ISO 389-7:1998

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Merknad: Denne standarden har en ny utgave: NS-EN ISO 389-7:2019

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This part of ISO 389 specifies a reference threshold of hearing for the calibration of audiometric equipment used under the following conditions: A) The sound field in the absence of the listener consists of either a free progressive plane wave (free field) or a diffuse sound field. In the case of a free progressive plane wave, the source of sound is directly in front of the listener (frontal incidence). NOTE 1 Correction values for the threshold of hesring under free-listening conditions and selected angles of sound incidence deviating from frontal incidence are given in ISO 8253-2 for information. B) The sound signals are pure (sinusoidal) tones in the case of free-field conditions, and one-third octave band of (white or pink) noise in the case of diffuse-field conditions. C) The sound pressure level is measured in the absence of the listener at the position where the centre of the listener`s head would be. D) Listening is binaural. E) The sound pressure levels corresponding to the reference threshold of hearing are determined by the median value of the thresholds of an adequately large group of listeners. F) The listener are otologically normal persons in the age range from 18 to 25 years inclusive. NOTE 2 The data given in this part of ISO 389 have been derived from listeners who have hearing threshold levels og 10 dB or less according to ISO 389:1991. This selection criterion is not identical with that used when data for ISO 389:1991 were derived. G) The threshold of hearing is determined by means of the bracketing or ascending method, as specified in ISO 8253-1. The data are given in numerical form for the preddered frequencies in the one-third-octave series from 20 Hz to 16 000 Hz inclusive, in accordance with ISO 266 and for intermediate audiometric frequencies. Figure 1 gives a graphical presentation. It should be emphasized that the threshold data differ from the audiometric zero specified in ISO 389:1991 and ISO 389-2, since the latter refer to monaural listening through earphones with sound pressure levels reffered to specified couplers and ear simulators. Direct comparison between the data in ISO 389:1991 or ISO 389-2, respectively, and in this part of ISO 389 is therefore not appropriate.

Dokumentinformasjon

  • Standard fra SN
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  • Utgave: 1
  • Versjon: 1
  • Varetype: NAT
  • Products.Specs.pages
  • ICS 13.140
  • National Committee SN/K 1

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