The Heath Aqua-Scope consists of two major components; the direct contact microphone
and ground microphone.
Use a high-frequency electronically filtered/amplified contact microphone
to listen for leak sounds on all meters, valves, hydrants, and other contact points.
Alternatively, the NB 3000 completes the NB-Series with a high performing contact microphone
Their first commercial product, known as "the stethoscope", uses MSI's piezo film as a contact microphone
sensor along with low-noise electronics to provide an electronic signal of high quality that can be amplified, transmitted, stored, and analysed.
The AQUA-SCOPE allows an operator to choose between the ground and direct contact microphones
to detect sonic frequencies.
Indisputably, Cage impacted tremendously the musical establishment; however, the composer received mixed receptions to his work throughout his lifetime, acquiring either accolades or hostility, such as the 1964 performances of Atlas Eclipticalis by the New York Philharmonic, in which orchestral players sabotaged the performance by ignoring the notated music and destroying the contact microphones
used in the work.
In this instance, Tudor sent the resulting sounds out to various objects (the score calls for eight), on which he placed contact microphones
, so that they too became part of the feedback circuit.