What key am I playing in?

[Sosan]

SO I created a chord progression that goes:

BbMaj9
EbMin9
GMin9
GbMaj9
BMaj9

Now my question is what key am I playing in? If I'm playing more than one, which chord is the tonic and why do the two different keys work together?

Thought it was Db Major until I hit the flatted 7th which would make it mixolydian mode correct? Then I jumped to play Gb Major over the GbMaj9 chord but it doesn't sound right.. Gb lydian sounds right.. I'm stumped.. and trying to figure out why I like the chord progressions I like.. Thanks in Advance!

 

[bandcoach]

progression

BbMaj9 - EbMin9 - GMin9 - GbMaj9 - BMaj9

notes in chords

BbMaj9 ~ Bb-D-F-A-C
EbMin9 ~ Eb-Gb-Bb-Db-F
GMin9 ~ G-Bb-D-F-A
GbMaj9 ~ Gb-Bb-Db-F-Ab
BMaj9 ~ B-D#-F#-A-C#

scale structure(s)

Bb-D-F-A-C-Eb-Gb-Bb-Db-F-G-Bb-D-F-A-Gb-Bb-Db-F-Ab-B-D#-F#-A-C#

arrange alphabetically

Ab-A-A-A-Bb-Bb-Bb-Bb-B-C-C#-Db-Db-D-D-D#-Eb-F-F-F-F-F#-Gb-Gb-G

remove duplicates (including enharmonic equivalents)

Ab-A-Bb-B-C-C#-D-D#-F-F#-G

potential scales in use

Ab-Bb-C-Db-Eb-F-G (C#=Db, D#=Eb)

A-B-C#-D-(E)-F#-G#-A

Bb-C-D-Eb-F-G-A-Bb

B-C#-D#-(E)-F#-G#-A#-B (G#=Ab, A#=Bb)

Alternative naming of chords in the progression leading to Harmonic analysis

BbMaj9 - D#Min9 - GMin9 - F#Maj9 - BMaj9

B: bI9 - iii9 - bvi9 - V9 - I9

however V9 is a dominant function and the chord used is either subdominant or tonic in nature so we need to reconsider what is happening with F# as our tonic chord

A#maj9 - D#min9 - Gmin9 - F#maj9 - Bmaj9
F#: III9 - vi9 - bii9 - I9 - IV9

what we then can construct is the following

V-of-vi - vi - bii9 - I9 - IV9, which seems a reasonable progression in F# major

i.e. the first chord is a secondary dominant substitution but with a tonicised function as well - although I would like to know what notes you have in each chord at your side of the question - i.e. we may in fact have an issue of misnaming of some of the chords

bii9 can be considered a planing tritone substitution for C#9 in the progression

C#9 ~ C#-E#-G#-B-D# cf Gm9 ~ G-Bb-D-F-A

C#9	Gm9	Movement/voice leading
D#	D	Down semitone
B	Bb	Down semitone
G#	A	Up Semitone
E#	F	equivalent
C#	G	Up/Down a Tritone

now consider voice leading from C#9-F#maj9 and Gm9 to F#maj9

C#9	F#maj9	Movement/voice leading
D#	C#	Down tone
B	A#	Down semitone
G#	G#	equivalent
E#	E#	equivalent
C#	F#	Up a 4th/Down a 5th

Gm9	F#maj9	Movement/voice leading
D	C#	Down semitone
Bb	A#	equivalent
A	G#	Down semitone
F	E#	equivalent
G	F#	Down semitone