Abstract: An acoustic apparatus includes a threaded stud having an end and a hole in the end, an acorn nut having a hole therein, and an acoustic sensor received in the hole of the stud and secured to the stud and acorn nut when the acorn nut is screwed onto the stud, thereby sandwiching the acoustic sensor between the stud and the acorn nut. This apparatus can be included in an acoustic sensor assembly, such as an acoustic monitor field unit or a remote acoustic sensor assembly.