Originally Posted by: cj.stevens

I'm working my way through Guitar Fundamentals 2 and Lisa McCormick has a song "Follow the Arrows'. In the notes she writes 'The chord in the song 'Asus2' is also frequently called 'Aadd9', in other musical contexts'

Can you explain the theory behind that statement, and what is meant by other musical contexts?

chris

unfortunately there's some blurring, coming from being able to play Asus2 instead of Aadd9 or vice versa, in that particular song.

the song may be in A Major or D Major or E major. These keys will support Aadd9, instead of or, as well as Asus2.

You can see how Asus2 could be used instead of Aadd9 in certain musical contexts. But not all.

Asus2 is spelt 1 2 5 whereas Aadd9 is spelt 1 3 5 9

the key possiblities for these chords (Major Scales only) follow

Aadd9 could be chord 1 in A Major, chord 4 in E Major,chord 5 in D Major,

Asus2 appears as chord 1 in A, chord 2 in G ,chord 4 in E ,chord 5 in D and chord 6 in C .

Asus2 in G and C would need to be played as Am add9, to remain diatonically correct.

please see this pdf. its free to download and share, no sign up or anything.

it shows the possibilities of every chord in every Major key.

https://kingofchordsblog.files.wordpress.com/2016/02/chord-possibilities-in-major-keys.pdf