Originally Posted by: pvirenThanks! that link explained a lot :)

Could someone explain me what is a perfect fifth, or seventh with respect to a guitar? And what are harmonics?

Forgive me if these questions are too vague, but thats the level of confusion that i am in right now :(

All modal intervals (2nd, 3rd, 6th, 7th) can be either major, minor, agumented, or diminished. Tonal intervals (1st, 4th, 5th) are called perfect intervals. They are supposed to never be changed. Although sometimes you can find an augmented or diminished 4th or 5th interval.

The 7th is the 7th interval of the root. There are 7 different types of 7th chords. They are made by adding the 7th of a triads root to a triad.