#1
hi
so i want to know when start writing a song (sad , happy , love, or anything)
the tonic you chose is important too or the scale you chose is what that form the feeling and type of the song ?
for ex. if i whant to write song in phrygian mode for partially sad song the tonic i chose is important also ?
#2
Actually the tonic isn't important. The mood of the song is actually given as intervals. One note sounds like one note, but when followed by another it is given context, much like words in a sentence.

Generally it's thought that Major is the more optimistic and Minor the more pessimistic (Ionian and Aeolian respectively). However, the theory FAQ has information on the feel of particular modes, such as Locrian sounding more dark and disturbing, but being very volatile to work with.
#3
Actually the tonic isn't important. The mood of the song is actually given as intervals. One note sounds like one note, but when followed by another it is given context, much like words in a sentence.

Generally it's thought that Major is the more optimistic and Minor the more pessimistic (Ionian and Aeolian respectively). However, the theory FAQ has information on the feel of particular modes, such as Locrian sounding more dark and disturbing, but being very volatile to work...wait, damn beaten to it