Loudness vs. sound pressure (<a class="external text" href="https://en.wikipedia.org/wiki/Robinson%E2%80%93Dadson_curves">Robinson-Dadson equal loudness curves</a>, <a class="external text" href="https://en.wikipedia.org/wiki/ISO_226">ISO 226:1987</a>)
<a href="//commons.wikimedia.org/wiki/User:Monedula" title="User:Monedula">Monedula</a>
2005-07-19
<a class="external text" href="https://en.wikipedia.org/wiki/ISO_226">ISO 226:1987 ISO 226:1987</a>