You don’t say what sort of acoustic test was agreed at mediation.
Acoustic testing in this context is typically conducted using a tapping machine on the hard surface floor and the sound measurement would be made in the apartment below. So as the affected neighbour you will be very much witness to the process.
There are different types of noise – what needs be measured is the noise transmitted through the floor with the ambient noise generated within the apartment above being of no direct relevance.
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