I am trying to learn about frequency domain and I am using audacity software. I selected a small YouTube video (link below):
I converted it to .wav format using the link below: https://youtubeto.org/en/youtube-wav.html
When I imported this .wav file into my audacity and tried to analyze its frequency spectrum, I got a new frequency analysis window (as shown in attached snap). But I am unable to understand it as I have two confusions:
In our books we saw frequency spectrum where zero frequency is at center and here in this plot zero frequency is at left.
Why do we have here a negative sign with db values, what does that mean? -11 db has lowest magnitude/amplitude and 90 db has highest magnitude/amplitude or is it the opposite ?