Figure 4.1   Opening of Moonlight Sonata

This spectrogram was digitally synthesized, using MuseScore, from the first three measures of the Moonlight Sonata:

The recording is played too fast and too dynamically.  Here is a spectrogram from the beginning of a performance by Claudio Arrau.

The passage begins at 0.05.  You can listen to it on Spotify:

You can buy the recording from Amazon, or iTunes, or Spotify.