<p class="MsoBodyText" style="mso-layout-grid-align: none; text-autospace: none;"><span lang="EN-GB" style="mso-bidi-font-size: 12.0pt;">This document specifies combinations of sound pressure levels and frequencies of pure continuous tones which are perceived as equally loud by human listeners. The specifications are based on the following conditions:</span></p>
<p class="ListNumber1" style="margin-bottom: 9.0pt; tab-stops: 19.85pt 39.7pt 59.55pt 79.4pt 99.25pt 119.05pt 138.9pt 158.75pt 178.6pt 7.0cm; mso-layout-grid-align: none; text-autospace: none;"><span lang="EN-GB" style="mso-bidi-font-size: 12.0pt;">a)<span style="mso-tab-count: 1;"> </span>the sound field in the absence of the listener consists of a free progressive plane wave;</span></p>
<p class="ListNumber1" style="margin-bottom: 9.0pt; tab-stops: 19.85pt 39.7pt 59.55pt 79.4pt 99.25pt 119.05pt 138.9pt 158.75pt 178.6pt 7.0cm; mso-layout-grid-align: none; text-autospace: none;"><span lang="EN-GB" style="mso-bidi-font-size: 12.0pt;">b)<span style="mso-tab-count: 1;"> </span>the source of sound is directly in front of the listener;</span></p>
<p class="ListNumber1" style="margin-bottom: 9.0pt; tab-stops: 19.85pt 39.7pt 59.55pt 79.4pt 99.25pt 119.05pt 138.9pt 158.75pt 178.6pt 7.0cm; mso-layout-grid-align: none; text-autospace: none;"><span lang="EN-GB" style="mso-bidi-font-size: 12.0pt;">c)<span style="mso-tab-count: 1;"> </span>the sound signals are pure tones;</span></p>
<p class="ListNumber1" style="margin-bottom: 9.0pt; tab-stops: 19.85pt 39.7pt 59.55pt 79.4pt 99.25pt 119.05pt 138.9pt 158.75pt 178.6pt 7.0cm; mso-layout-grid-align: none; text-autospace: none;"><span lang="EN-GB" style="mso-bidi-font-size: 12.0pt;">d)<span style="mso-tab-count: 1;"> </span>the sound pressure level is measured at the position where the centre of the listener's head would be, but in the absence of the listener;</span></p>
<p class="ListNumber1" style="margin-bottom: 9.0pt; tab-stops: 19.85pt 39.7pt 59.55pt 79.4pt 99.25pt 119.05pt 138.9pt 158.75pt 178.6pt 7.0cm; mso-layout-grid-align: none; text-autospace: none;"><span lang="EN-GB" style="mso-bidi-font-size: 12.0pt;">e)<span style="mso-tab-count: 1;"> </span>listening is binaural;</span></p>
<p class="ListNumber1" style="margin-bottom: 9.0pt; tab-stops: 19.85pt 39.7pt 59.55pt 79.4pt 99.25pt 119.05pt 138.9pt 158.75pt 178.6pt 7.0cm; mso-layout-grid-align: none; text-autospace: none;"><span lang="EN-GB" style="mso-bidi-font-size: 12.0pt;">f)<span style="mso-tab-count: 1;"> </span>the listeners are otologically normal persons in the age range from 18 years to 25 years inclusive.</span></p>
<p class="MsoBodyText" style="mso-layout-grid-align: none; text-autospace: none;"><span lang="EN-GB" style="mso-bidi-font-size: 12.0pt;">The data are given in graphical form in <span class="citeapp"><span style="color: black; mso-color-alt: windowtext; border: none;"><span style="border: none;">Annex A</span></span></span> and in numerical form in <span class="citeapp"><span style="color: black; mso-color-alt: windowtext; border: none;"><span style="border: none;">Annex B</span></span></span> for the preferred frequencies in the one-third-octave series from 20 Hz to 12 500 Hz, inclusive, in accordance with <span class="stdpublisher"><span style="color: black; mso-color-alt: windowtext; border: none;"><span style="border: none;">ISO</span></span></span> <span class="stddocNumber"><span style="color: black; mso-color-alt: windowtext; border: none;"><span style="border: none;">266</span></span></span>.</span></p>
Registration number (WIID)
83117
Scope
<p class="MsoBodyText" style="mso-layout-grid-align: none; text-autospace: none;"><span lang="EN-GB" style="mso-bidi-font-size: 12.0pt;">This document specifies combinations of sound pressure levels and frequencies of pure continuous tones which are perceived as equally loud by human listeners. The specifications are based on the following conditions:</span></p>
<p class="ListNumber1" style="margin-bottom: 9.0pt; tab-stops: 19.85pt 39.7pt 59.55pt 79.4pt 99.25pt 119.05pt 138.9pt 158.75pt 178.6pt 7.0cm; mso-layout-grid-align: none; text-autospace: none;"><span lang="EN-GB" style="mso-bidi-font-size: 12.0pt;">a)<span style="mso-tab-count: 1;"> </span>the sound field in the absence of the listener consists of a free progressive plane wave;</span></p>
<p class="ListNumber1" style="margin-bottom: 9.0pt; tab-stops: 19.85pt 39.7pt 59.55pt 79.4pt 99.25pt 119.05pt 138.9pt 158.75pt 178.6pt 7.0cm; mso-layout-grid-align: none; text-autospace: none;"><span lang="EN-GB" style="mso-bidi-font-size: 12.0pt;">b)<span style="mso-tab-count: 1;"> </span>the source of sound is directly in front of the listener;</span></p>
<p class="ListNumber1" style="margin-bottom: 9.0pt; tab-stops: 19.85pt 39.7pt 59.55pt 79.4pt 99.25pt 119.05pt 138.9pt 158.75pt 178.6pt 7.0cm; mso-layout-grid-align: none; text-autospace: none;"><span lang="EN-GB" style="mso-bidi-font-size: 12.0pt;">c)<span style="mso-tab-count: 1;"> </span>the sound signals are pure tones;</span></p>
<p class="ListNumber1" style="margin-bottom: 9.0pt; tab-stops: 19.85pt 39.7pt 59.55pt 79.4pt 99.25pt 119.05pt 138.9pt 158.75pt 178.6pt 7.0cm; mso-layout-grid-align: none; text-autospace: none;"><span lang="EN-GB" style="mso-bidi-font-size: 12.0pt;">d)<span style="mso-tab-count: 1;"> </span>the sound pressure level is measured at the position where the centre of the listener's head would be, but in the absence of the listener;</span></p>
<p class="ListNumber1" style="margin-bottom: 9.0pt; tab-stops: 19.85pt 39.7pt 59.55pt 79.4pt 99.25pt 119.05pt 138.9pt 158.75pt 178.6pt 7.0cm; mso-layout-grid-align: none; text-autospace: none;"><span lang="EN-GB" style="mso-bidi-font-size: 12.0pt;">e)<span style="mso-tab-count: 1;"> </span>listening is binaural;</span></p>
<p class="ListNumber1" style="margin-bottom: 9.0pt; tab-stops: 19.85pt 39.7pt 59.55pt 79.4pt 99.25pt 119.05pt 138.9pt 158.75pt 178.6pt 7.0cm; mso-layout-grid-align: none; text-autospace: none;"><span lang="EN-GB" style="mso-bidi-font-size: 12.0pt;">f)<span style="mso-tab-count: 1;"> </span>the listeners are otologically normal persons in the age range from 18 years to 25 years inclusive.</span></p>
<p class="MsoBodyText" style="mso-layout-grid-align: none; text-autospace: none;"><span lang="EN-GB" style="mso-bidi-font-size: 12.0pt;">The data are given in graphical form in <span class="citeapp"><span style="color: black; mso-color-alt: windowtext; border: none;"><span style="border: none;">Annex A</span></span></span> and in numerical form in <span class="citeapp"><span style="color: black; mso-color-alt: windowtext; border: none;"><span style="border: none;">Annex B</span></span></span> for the preferred frequencies in the one-third-octave series from 20 Hz to 12 500 Hz, inclusive, in accordance with <span class="stdpublisher"><span style="color: black; mso-color-alt: windowtext; border: none;"><span style="border: none;">ISO</span></span></span> <span class="stddocNumber"><span style="color: black; mso-color-alt: windowtext; border: none;"><span style="border: none;">266</span></span></span>.</span></p>
