The song is "Let me love you" by Mario, which is in the key of G minor. In the verse and the chorus, Cm7 - Gm7 - F chords are used, which is the iv, i and VII of the G minor natural scale. However, in the bridge they use the chords (Abmaj7 - Ebmaj7 - Gbmaj7 - Dbmaj7) and (Abmaj7 - Ebmaj7 - Gbmaj7 - Bbsus4) .Can someone tell from which scale or mode did they borrow these chords from? Thank you.
Scale tones in G Aeolian = G A Bb C D Eb F
Some extrapolated chords = Gm7, Cm7, FM, EbM7, Bbsus4
The AbM7 is only one half step off (A instead of Ab); the C, Eb, and G are already in the scale. It's impossible to know with certainty the songwriter's process without asking them but perhaps they just liked the sound of a chromatic raise (as so many writers have done). The bridge progression is a common pattern, and making chords into 7ths whether they be dominants or Maj7 is a common practice (even if the scale doesn't include all of the needed tones). For example, playing D7 (V7) would be a common choice and would not indicate a change of scale/mode (though technically we would call this G harmonic minor instead of natural minor). Similarly, many Jazz and Blues soloists will use minor pentatonic runs over a Major triad. Genre can play a determining factor in when it's OK to stray.
Ab Mixolydian scale gives you all the root notes of the progression (Ab - Eb - Gb - Db) so perhaps he's using that mode and then altering each where needed to make them into Maj7 chords.
Ab Ionian (Ab Bb C Db Eb F G) and G Phrygian (G Ab Bb C D Eb F) both have the notes necessary to make the AbM7 chord plus the original chord progression in the beginning of the song.
Songwriting-composing is a different process for everyone, and can even vary from song to song. Sometimes you're just doing what feels right. Scales and modes are important and useful knowledge, though. Hope this was helpful!
You really have to listen to the song to determine what the harmonies are doing here. Otherwise, you're just guessing.
After listening to the song, I agree that the song is in G minor, but I also feel a pretty strong pull to B♭ major, the relative major key, right on that F chord. This is a loop of three chords, and I think there's definitely merit in analyzing the progression from both the major and minor key perspective (two key centers in a loop can be labelled bitonicity). On to the bridge:
When I heard the bridge, I heard the A♭maj7 chord and picked up that the song was going to a new place in the flat direction. The E♭maj7 chord makes it clear that E♭ is the key center, which was arrived at via the IVmaj7 Imaj7 progression. When we lift up to G♭maj7, there's a feeling not only that we're moving to an even flatter soundscape, but there's the sense that we've moved to the parallel minor, in a way: this chord change is reminiscent of E♭maj7 E♭m7, which would be the parallel shift that the G♭ chord implies. However, since I had already heard the IVmaj7-Imaj7 move earlier, it came as no surprise when the song touched down on D♭maj7. The song started out in two flats, and is now in five. But we restart this new bridge loop with A♭maj7 again, but instead of a full repetition, the D♭maj7 chord is replaced by B♭7sus. This B♭7sus chord starts our return to G minor/B♭ major, and the move is completed when two beats later we hear F/A - this F chord is the chord that always leads into the Cm7 in the verses and choruses.
Some broad general ideas:
- It's pretty common in R&B to hear a move into flatter keys (counterclockwise on the circle of fifths) in the bridge, especially using seventh chords like this song does.
- This part of the progression is a lot less about functional roles as it is about a colourful shifting harmony. Therefore, the exact chords used aren't super important; one could easily replace that D♭maj7 with Gm7, for example, for a similar effect.
- The IV-I plagal sound decorated with sevenths is established as a common motif in the bridge , providing a sense of unity to otherwise disjunct chords.
- The IV-I move is also potentially established in the main loop of the song, with Cm7-Gm being iv-i in G minor.
- I don't think it's useful to describe what's going on in the bridge as modal interchange, because the song seems content to make a full departure from the prevailing key signature of B♭/Gm. Instead, a concept called temporary tonicization comes to mind, where a new key center is introduced temporarily but can still feel resolved. It's very difficult to hear the D♭maj7 chord, for example, in relation to the key of B♭ major in context, but it's pretty easy to hear it as the I of D♭ major.
- Some of those maj7 chords actually get harmonised with their major ninths in the background vocals, but this only furthers my point that the key center is suspended and redefined rather than borrowing chords from other modes.
- The B♭7sus chord is a very idiomatic R&B harmony, and is much less directional than a reguar dominant seventh chord. Voiced tightly, it seems very natural moving to F/A.
As a songwriter, if you're going to do some complicated harmonies in your song, historically the bridge of the song has been the place to put them. The purpose of a bridge is often to provide something of a change from the previous sections, and in this case it could not have been clearer, since the entire song up to that point only uses three chords. Plus, the bridge historically has been a very common place to set up a modulation into a new key, since the last chorus typically follows the bridge, allowing the songwriter to get up into a kigher key for the end of the song.
This song leaves the prison of minor - major tonality and modes behind. But nevertheless we can hear a tonal center: is it Cm or is it F? or Gm - as you say?
I'd rather say: Cm - dorian (i v IV) The rest is a sequence of IV-I (or I-V) progressions in whole steps downward. Don't look to much for traditional harmonic analysis where there isn't any ...
Btw. : It reminds me of the music I've made with my chaps when we were 15 years old (about 100 years ago. ;)