For the next reviews, two evolutions in the graphs to simplify understanding.
- The first concerns the display of the spectrum. To allow a better comparison, the spectrum will display the curve of the current edition plus the curve of one of the other editions.
- The second concerns a new temporal representation of the bandwidth : the Spectrogram
For each channel (right and left), the bottom represents bass, the top represents treble. On the horizontal axis, the time.
The louder the level for a frequency is the lighter the color (we go from black to white, with the intermediate colors red, orange, etc.).
There is a link between the different graphs. The graph below shows the links between the 3 graphs.
- The pic of the waveform can produce line in the frequency representation (white lines).
- The horizontal variation represents the bandwidth (black lines).
Adding source of old albums.
The Bibliothèque nationale de France (BnF) Collection sonore with 45,000 online albums distributed on all musical platforms from LPs published between 1949 and 1962.