<?xml version="1.0" encoding="utf-8"?><mads xmlns="http://www.loc.gov/mads/" xmlns:mods="http://www.loc.gov/mods/v3" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.loc.gov/mads/
mads.xsd"><authority><topic authority="http://AATesaurus.cultura.gencat.cat/aat/getty_en">sound</topic></authority><related type="narrower"><topic>ultrasound</topic></related><related type="other"><topic>soundproofing</topic></related><related type="broader"><topic>acoustics concepts</topic></related><variant type="other"><topic>sounds</topic></variant> <note xml:lang="en"><![CDATA[ Mechanical disturbance from a state of equilibrium that propagates energy through air, water, or another elastic medium. It is responsible for the sensation of hearing, although it also includes energy waves that cannot be heard by the human ear but can be detected by sonar equipment and other devices. ]]></note></mads>