Sound of ringing gels
From this question on Physics SE, there is a linked audio track in Soundcloud here, which is what you are looking for. The OP references a jar of hair-stying gel which, upon being tapped with a mallet, produces a &quot;reverberating&quot; sound instead an otherwise expected &quot;short 'tok' sound.&quot;
Note the the ringing gels are common ingredients in pomades, shampoos, and other products where rheological properties are engineered for various reasons. See this patent application for a ringing gel, wherein it is stated:

The phenomenon of ringing is a result of the manner in which the dispersed droplets are entrapped within the network structure of a gel. It has been suggested that the network within a gel consists of a rod-like or lamellar structure. Such a network could allow dispersed particles to vibrate within a gel much like a ball bounces off the walls of a box.

The practical application of the gels appears to be mainly in the cosmetics industry.