Hi, I am just trying to understand the output of a sound spectrum analyzer. There are three dimensions 1) Time 2) Frequency 3) Volume (db) I am confused about few things here: 1) How should I perceive the volume dimension here? 2) Why are the db values negative here and w.r.t what reference value are they negative? The standard equation for the volume (sound) is 20(log(value/refvalue) to base 10), right? 3) Also I don't really understand the reason behind multiplying the log output with 20 here. What does it signify? I have attached the spectrum analyzer output. Thanks in advance!