Forum: music.stackexchange.com
Tags: <theory><chords><chord-theory>
Title: Notes in a lick that don't fit in the scale associated with the chord
Question: Hello! Could someone please give me an explanation about why in the above lick they use G flat (yellow square) instead of G and an E (red circle) instead of E flat, as the Gm dictates?  Thank you in advance!

Answers:
sents: text: You could ask the same about the A note.
text: All three are just passing notes, passing from one 'good' note to another 'good' note.
text: I call them stepping stone notes.
text: They come on unstressed parts of the bar.
text: The stressed points usually being beats 1 and 3.
text: Here the A is & of 1, Gb & of 3 and E & of 4, all weak points where almost any note will not sound too bad.
text: Gb>
text: F>
text: E is a chromatic run, possibly ending on a chord tone on the important 1 in the next bar,
text: Eb perhaps, part of Cm chord?
text: All this presumes it's in key C, with the C key sig - no # or b.
text: The 'Gm7' dictates nothing.
text: Except that's the chord appropriate in that bar.
text: There's no 'rules' (as we keep saying!); there's only 'theory'.
text: Often in a bar of Gm7 there will be some chord tones - G, Bb, D, F, but that certainly does not preclude use of any of the remaining eight notes, whatever key the piece happens to be in.
text: That concept you (and so many others) adhere to is wrong!
answer_details: author: music.stackexchange.com/users/2808/Tim
score: 11
sents: text: In general, not every note needs to be considered part of the harmony.
text: You can have notes outside of a chord or key be utilized.
text: Both of these notes are examples of non harmonic tones.
text: The G&flat; is a chromatic passing tone.
text: It is sandwiched between the G and F which are both chord tones.
text: The E is also most likely another non harmonic tone, what it is exactly depends on what comes next.
text: It could be another chromatic passing tone if the next note is an E&flat;, it could just as easily be an anticipation of what is next especially if you are in the key of A minor or C major which the lack of accidentals in the key signature.
answer_details: author: music.stackexchange.com/users/7222/Dom
score: 6
sents: text: Although for this particular phrase the easiest explanation is "they're simply passing notes
text: " it's worth noting
text: these particular passing notes are a bit like a magic ingredient in the sound of jazz as they are part of jazz minor scale, almost a classic sound in jazz.
text: So if you start digging more and analyzing jazz recordings you will come across phrases where the sixth and major seventh over minor chords function as a static tension or a harmonic "color" that doesn't really get resolved.
answer_details: author: music.stackexchange.com/users/57539/Jarek.D
score: 6
sents: text: Context is important when trying to understand what the chords are doing, but the Gm7 could be a ii chord, perhaps part of a ii-V7-I progression.
text: The Dorian scale is often used to create phrases over ii chords, and G Dorian includes an E, not an Eb.
text: In fact, the natural sixth degree (the E) is the note that gives Dorian its character.
text: In this interpretation, the only other note that needs explaining is the Gb.
text: It is, of course, just a chromatic passing note.
text: But more can be said.
text: Bebop players used to add certain chromatic passing notes to smooth out their phrases; this phrase can be seen as constructed from the G Bebop Dorian scale , with a Gb written in place of F#.
text: In other words, this phrase is typical of what might be played over a ii chord in the Bebop idiom.
answer_details: author: music.stackexchange.com/users/39614/ex nihilo
score: 3
sents: text: The technical term is non-chord tones .
text: The other answers already explain these particular NCT's are unaccented passing tones, but there is a complete nomenclature of NCT from classical music that you should review to see the wide range of possibilities.
text: In homophonic (chord based) music a huge amount of melody can be explain as the interplay of chord tones following the harmony and non-chord tones.
text: https://en.wikipedia.org/wiki/Nonchord_tone
text: In jazz there is a special type of NCT called an enclosure which you should also review.
text: https://www.jazzadvice.com/how-to-effectively-use-enclosure/ The chord/scale system in jazz is an alternate approach from the classical non-chord tones theory.
text: But some other questions/answers here at StackExchange explain that historically - prior to the chord/scale system - jazz improv was largely arpeggiated chords embellished with non-chord tones.
text: The two systems shouldn't be considered mutually exclusive.
text: You might want to expand this single question to a general review of the whole topic of non-chord tones.
text: It will deepen your understanding of melody.
answer_details: author: music.stackexchange.com/users/23919/Michael Curtis
score: 3

Summary of the answers:
In general, not every note needs to be considered part of the harmony.  You can have notes outside of a chord or key be utilized. In homophonic (chord based) music a huge amount of melody can be explain as the interplay of chord tones following the harmony and non-chord tones. 
Context is important when trying to understand what the chords are doing.