I’ve been checking out a lot of tabs lately and I’m wondering what defines really the choice of the mode. I know everything is related to each other and that choosing A minor would be the same thing as choosing C major or even choosing D dorian in that case, just like saying that 1 meter is equal to 100 cm. But what defines the mode chosen? I know most of modern music is either written in major or minor but is there a certain rule for that? Like taking the first chord and defining it as the “home chord” and choosing the mode accordingly or is it the melody that dictates it?
it’s often somewhat ambiguous, and frankly a lot of the stuff in the database would be better analyzed in major. Typically you would use the mode if there’s an unambiguous chord that feels like home base (and in this case you would choose the mode that make this chord the ‘one’ )
A mode that isn’t Ionian (major) or Aeolian (minor) is defined by the characteristic scale degrees that set it apart from the mode it is based on and similar modes. Some examples:
Major-like:
Lydian: ♮3, ♯4, ♮7
Lydian Dominant: ♮3, ♯4, ♭7
Mixolydian: ♮3, ♮6, ♭7
Minor-like:
Dorian: ♭3, ♮6, ♭7
Phrygian: ♭2, ♭3
Phrygian Dominant: ♭2, ♮3
Harmonic Minor: ♭3, ♭6, ♮7
Melodic Minor: ♭3, ♮6, ♮7
Locrian: ♭2, ♭3, ♭5
If a tab keeps using notes from a mode even when those notes do not appear in the chords (e.g. always using ♮6 over i chords), then the tab can be assumed to be in that mode; Major and Minor are the modes to use only when no other modes are implied (which however encompass a large portion of music).
