<p>A 110Hz A sine wave (magenta) and a 104Hz G# one (cyan). Their sum (blue) and the corresponding envelope (red).
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See: <a href="//commons.wikimedia.org/wiki/File:Beat_-_superposition_of_104hz_and_110hz_sine_waves.ogg" title="File:Beat - superposition of 104hz and 110hz sine waves.ogg">File:Beat - superposition of 104hz and 110hz sine waves.ogg</a>
No machine-readable author provided. <a href="//commons.wikimedia.org/wiki/User:Barak_Sh" title="User:Barak Sh">Barak Sh</a> assumed (based on copyright claims).
No machine-readable source provided. Own work assumed (based on copyright claims).