Let’s take a look at some more real world application of the modes.

It seems that the vast majority of the time, discussion of the modes is centered around soloing concepts. Consequently, many “groove” bassists tend to discount modes as irrelevant to their musical needs.

However, in my opinion, the most valuable aspect of the modes is that they allow a musician to know what the “rules” of western harmony would prescribe based upon a given key.

Let me expound.

Based upon our snapshot memorization of the modes, we should now know that in the key of G major...

...a chord built on C would be:

M7 (or simply major, if not voicing the 7th’s) in quality, and the appropriate scale to play would be C Lydian; and

...a chord built on A, it would be:

m7 (or simply minor, absent the 7th) in quality, and the appropriate scale to play would be A Dorian.

IMPORTANT NOTE: For creative purposes, the composer or arranger might very well tweak with the above harmony by changing the chord qualities to C-7 or A7, which is perfectly cool (as a matter of fact, those sorts of deviations from diatonic harmony can create interest, simply because of the unexpected nature of those reharmonizations). However, the value of the modes is that the musician can know what the “default” chord qualities and corresponding scales should be, given the key of the piece. That allows the player to confidently negotiate the harmony while discerning and accommodating when “curves are being thrown” for specific compositional or arrangement intent.

Please re-read the preceding paragraph, if necessary; it’s a critical point to grasp relative to our mode studies.

Let’s evaluate a few chord progressions. To allow for actual harmonic analysis (versus simply reading the key signature!) in the following exercises, the key signature isn’t indicated on the staff.

EXERCISE 1

Based upon the four chords reflected, and assuming no deviations or harmonic twists, determine the key of this piece. Take a moment to do this now, then compare your conclusion to the following.

Analysis:

If you were to assume that the key is D, the first 3 bars would be consistent:

D Ionian, which reconciles with the DM7,
F# Phrygian, which reconciles with the F#-7
B Aeolian, which reconciles with the B-7...

...but the E7 in the fourth bar is a departure, isn’t it? Based upon the key of D, we would expect to see an E-7 chord, to which E Dorian would correspond.

Are there any other possibilities? What if DM7 is actually the chord built on the 4th degree of the key?

That would mean:

D Lydian, which also reconciles with DM7,
F# Aeolian, which also reconciles with F#-7,
B Dorian, which also reconciles with B-7,

and

Mixolydian, which reconciles with E7!

So this progression is in the key of A.

Play the arpeggios and appropriate modes for this chart. Listen to how the variations between the different modes keep them harmonically consistent to the key of A.

Video Exercise 1

 
 

EXERCISE 2

 
 

Again, assuming no deviation from diatonic harmony, what is the key? Give it a shot, then compare to the following.

ANALYSIS:

If we were to assume the key of E minor (or G, the relative major), that would mean:

E Aeolian, which corresponds with the E-7 chord,
B Phrygian, which corresponds with the B-7 chord,
G Ionian, which corresponds with the GM7 chord...

...but F# Locrian would not reconcile with the F#-7 chord (remember that the Locrian mode would call for a flat 5th).

How about the key of D (or B minor, its relative minor)? That would mean:

E Dorian, which is compatible with the E-7 chord,
B Aeolian, which is compatible with the B-7 chord,
G Lydian, which is compatible with the GM7 chord, and
F# Phrygian, which is compatible with the F#-7 chord.

So based upon no departures from diatonic harmony, the key is D.

Play through the chart in arpeggios, then the correct modes in this key.

Video Exercise 2

 
 

EXERCISE 3

 
 

Evaluate this chart and determine the key.

Analysis:

You might be noticing a trend, in that I haven’t been incorporating the tonic M7 chord (i.e., the major chord built on the 1st degree of the key)! After all, how boring would THAT be? ha

If you concluded that:

C Lydian corresponds with CM7,
E Aeolian corresponds with E-7, and
G Ionian corresponds with GM7...

...you would be correct! The key is G.

Play the arpeggios and modes for this chart.

Video Exercise 3

 
 

EXERCISE 4

 
 

Evaluate the harmony in this chart.

Analysis:

Let’s see...F Lydian, A Aeolian, and...G Mixolydian? Not quite. The G-7 chord definitely doesn’t reconcile with G Mixolydian, which would call for G7.

Yes, I’ve FINALLY thrown you an example where the first chord IS, in fact, the tonic major chord. The key is F.

In our final exercise, we’ll incorporate a deviation from diatonic harmony.

Generally speaking, if we encounter a harmonic departure or twist, it’s important to quickly determine whether the deviation is:

an isolated reharmonization (frequently dictated by the idioms of the particular musical style),

or

a key change.

Isolated reharmonizations will be relatively easily identified as we gain experience and develop a broad vocabulary of musical genres: certain styles of music employ recurring harmonic substitutions that will be recognized as idioms of those styles.

On the other hand, if the deviation occurs at the beginning of a long section of music where EVERYTHING appears to be departing from the expected chord qualities...then there’s a decent likelihood that the key has changed, in which case transposing the modes to the appropriate key should bring everything back into focus! A common example would be jazz tunes where key changes frequently occur every several bars with II-V-I cadences.

EXERCISE 5

 
 

Evaluate the harmony, and see if you can identify both the key and the deviation.

Analysis:

Yes, the key is G minor (or Bb, its relative major).
G Aeolian reconciles with the G-7 chord,
C Dorian reconciles with the C-7 chord,
Eb Lydian reconciles with the EbM7 chord,
D Phrygian reconciles with the D-7 chord, and
Bb Ionian reconciles with the BbM7 chord.

The harmonic substitution occurred with the D7 (versus the D-7 chord and D Phrygian mode that the key of Bb major/G minor would normally prescribe). This is a VERY typical reharmonization in R&B or pop contexts. It should definitely be viewed as a momentary deviation from the key (an accidental), as opposed to a key modulation.