FREQUENCIES

Here is a table grouping the keys by range,
and showing you the frequencies in hertz for each note.

To make things easier, all the half tones are written with a "#"...
If you are familiar to read some of these half tones with the flat extension (b),
here is a little table with equivalences:

A#=Bb

G#=Ab

F#=Gb

D#=Eb

C#=Db