I want to measure the individual loudness level of a device in environment.
Fistly, I measure loudness level when the device is ON (95.5dB) Then I measure loudness level when the device is OFF (48.5dB)
The engineer said that the device loudness level is 95.5-48.5=47dB
But I think it must be ~95.5 because it still depending in many factor such as: environment sound frequency and device sound frequency...