What do the symbols on the sound spectrum stand for?

A semitone sign (#) indicates that the basic volume is raised by a semitone.

The semitone symbol (b) indicates that the basic volume is lowered by a semitone.

The polyphonic symbol (×) indicates that the basic sound level is raised by two semitones (a whole tone).

The sharp drop mark (bb) indicates that the basic volume has been lowered by two semitones (one full tone).

The lowering mark (ヰ) indicates that the raised or lowered sound is lowered.

There are three kinds, which are marked by dots (), triangles (▼) and dots and arcs, indicating that some sounds or chords should be played intermittently.