Am I doing the right thing to convert decibel from -120 - 0 to 0 - 120

Question

I will like to measure the sound volume of the surrounding, not too sure if I am doing the right thing.

I will like to create a VU meter of a range of 0(quiet) to 12

Answer 1

I make a regression model to convert the mapping relation between the wav data generated from NSRecorder and the decibel data from NSRecorder.averagePowerForChannel

NSRecorder.averagePowerForChannel (dB) = -80+6 log2(wav_RMS)

Where wav_RMS is root mean square value of wav data in a short time, i.e. 0.1 sec.