A Simple Way to Understand Modes for Guitar – Part 4
Once you’ve narrowed down your choice to the group of major or minor modes, here are some additional ideas & concepts that will help you determine which particular major or minor mode might work best against the song or progression that you’re playing over:
Ionian mode is the same as the Major scale, which we covered at the outset of this article. In the key of F Major, the “tonal center” or the bass note that would seem to fit against our entire progression would be F. When this happens, we get Ionian mode.
Here are some examples of songs which sound in Ionian mode for either the entire song or significant sections of the song: “American Pie” by Don McClean, “Angel Eyes” by Jeff Healey, “Authority Song” by John Mellencamp, “Beast of Burden” by the Rolling Stones, “Brown Eyed Girl” by Van Morrison, “Bubble Toes” by Jack Johnson, “Call Me Al” by Paul Simon, “Cliffs of Dover” by Eric Johnson, “Closer to Fine” by the Indigo Girls, “Down on the Corner” by CCR, “Drift Away” by Dobie Gray or Uncle Kracker, “Every Breath You Take” by the Police, “Family Tradition” by Hank Williams Jr., “Fool in the Rain” by Led Zeppelin, “Free Falling” by Tom Petty, “Friend of the Devil“ by The Grateful Dead, “Glycerine” by Bush, “Good Riddance (Time of Your Life)” by Green Day, “Heaven” by Los Lonely Boys, “Hey Good Lookin” by Hank Williams, “Hey Jude” by the Beatles, “Hit Me With Your Best Shot” by Pat Benatar, “Island in the Sun” by Weezer, “Jack and Diane” by John Mellencamp, “La Bamba” by Richie Valens or Los Lobos, “Last Kiss” by Pearl Jam, “Let It Be” by the Beatles, “Like a Rolling Stone” by Bob Dylan, “Mama I’m Coming Home” by Ozzy Osbourne, “Margaritaville“ by Jimmy Buffet, “Never Let You Go” by Third Eye Blind, “Red Red Wine” by UB40, “Ring of Fire” by Johnny Cash, “Satellite” by Dave Matthews Band, “Sister Golden Hair“ by America, “Sweet Home Alabama” by Lynard Skynard, “The Joker” by the Steve Miller Band, “Under the Boardwalk” by the Drifters, “Under the Bridge” by Red Hot Chili Peppers, “We Just Disagree” by Billy Dean, “Wonderful Tonight” by Eric Clapton, most of “Your Body Is A Wonderland” by John Mayer, … and countless other songs.
Advanced Theory: In the key of F major starting on the first degree – or F Ionian scale … our chord progression viewing it as relating to F major would be I, ii, iii, IV, V, vi, and viiÂ°. So a F Ionian chordal progression (remember we’re in the key of F) would feature the following chords: F, Gm, Am, Bb, C7 or C, Dm, Edim (or Em), F … So if you’re in a song where F is the I chord, and you see/hear these other chords in this relationship to each other: I Major, ii minor, iii minor, IV Major, V7 Dom 7 (or Major), vi minor, vii diminished (or substituted minor) — think F Ionian! … The most reliable indicators of Ionian mode are the Major I, IV & V chords, particularly if the V is a Dominant 7 or V7 chord, and/or ALL, or at least the vast majority of the chords, are diatonic chords built on the major scale of the I chord.
By playing against our sample progressions, certain ideas immediately pop out … if you hear a i to IV change, the Dorian mode, or the second mode, fits – you can take a natural minor scale based on the i and simply raise the sixth degree of the scale (i.e., play a major 6th instead of the typical minor 6th or b6 normally found in the natural minor scale). The reason this works is that you’re adjusting the scale to accommodate the major third necessary to create the IV chord. (You might also think of this movement as a common ii – V progression for the key on which the Dorian mode is constructed, i.e., you’d play the Dorian mode from the root of the ii chord). Dorian mode also works well over songs that have a i to bVII change – because the minor i chord is treated as the ii chord of the modal key and the bVII chord is treated as the I chord of the modal key. The appearance of a minor v chord, particularly against a Major IV chord, can also be characteristic of this mode. And the minor vi half step up to Major bVII distinguishes it from Aeolian. Dorian mode is frequently used in folk, rock, blues & jazz music.
To hear & recognize the sound of the Dorian mode, listen for example to “Oye Como Va” by Santana, “Whipping Post” by the Allman Brothers, “Horse With No Name“ by America, the traditional folk classic “Scarborough Fair“, “Another Brick in the Wall – part II” by Pink Floyd, “Badge” by Cream, “Evil Ways” by Santana, “Fly Like An Eagle” by the Steve Miller Band, “Godzilla” by Blue Oyster Cult, “Brick House” by the Commodores, “Golgi Apparatus” by Phish, “Le Freak” by Chic, “Riders on the Storm“ by the Doors, “Walking on the Sun” by Smash Mouth, “Who Will Save Your Soul” by Jewel, “Eleanor Rigby” by the Beatles, or even to the verse section in “Moondance“ by Van Morrison, or the solo section to “Light My Fire” by the Doors, or the solo section of “Your Body Is A Wonderland” by John Mayer).
Advanced Theory: In the key of F major starting on the second degree – or G Dorian scale … our chord progression viewing it as relating to F major would be ii, iii, IV, V, vi, viiÂ°, and I (and in chord progressions and songs constructed in all modes except Ionian or Locrian, the diatonic diminished chord is almost always skipped or another chord is substituted in it’s place in the progression*). So a G Dorian chordal progression (remember we’re in the key of F) would feature the following chords: Gm, Am, Bb, C, Dm (or D)**, (Em), F … So if you’re in a song where Gm is the i chord, and you see/hear these other chords in this relationship to each other: i minor, ii minor, bIII Major, IV Major, v minor (or sometimes V or V7 Major)**, vi minor* (or viDim)*, bVII Major — think G Dorian! … The most reliable indicators of Dorian mode are the Major IV and Major bVII chords in a minor i song or progression.
(*Note – since a diminished chord is built on a minor 3rd (or b3) and a b5, often you will often find a chord substituted at the spot in the diatonic modal progression where the diminished chord would otherwise appear – this could be a minor (since the diminished features a minor 3rd), or sometimes Major, built on the diminished root, or sometimes even a Major built 1/2 step below the diminished root – as frequently occurs where a bVII Major chord is substituted for the vii(Dim) chord in an Ionian Mode progression. **It is common even in songs built on minor keys or modes for a Major V or V7 to be substituted, although a minor v is reliable indicator that the song or progression is in a minor mode. Please also note that the chords that I’ve included in parenthesis simply refer to common substitutions that occur in progressions otherwise written in this mode, but that these substituted chords don’t purely fit the diatonic chords or notes of the major scale on which the mode is constructed. They are included because it’s helpful to recognize these common substitutions and not let their presence fool you into thinking that the song is not otherwise constructed in this mode. … Of course, it’s important to keep in mind that any time a chord is substituted for any one of the pure diatonic chords of the Major key on which the mode being employed is actually constructed, you can and might actually need to adjust your primary chosen modal scale, or even find and use a different modal scale, to pick up and include those chord tones/notes of the substituted chord which are not in the diatonic major scale on which the primary diatonic modal progression is constructed. If you find this idea confusing, there’s a specific example further clarifying this adjustment process & how to apply it at the very end of this article).
The Phrygian Mode, or the third mode, is uniquely characterized by it’s Spanish sound and flavor, and is thus sometimes also called the Spanish Gypsy scale. It is used most often against a half-step chord change from the minor i chord to the bII chord, or a substituted Major I chord to a bII chord. It resides in and exists because of the half-step between the 3rd & 4th degrees of the major scale. An example would be playing an E Phrygian scale constructed starting on the third scale degree of the C Major scale (or, you could also look at it as an A natural minor scale) over an E to F chord change, which is a very familiar use and a sound we’re all very familiar with. (So a shorthand way to find & play Phrygian mode for any note or chord that you’re on is to simply find the 4th of the note or chord you’re on & play a natural minor scale, but emphasize the Phrygian note – for example, for E Phrygian, play A natural minor – but emphasizing the mode root E … for D Phrygian, play G natural minor – but emphasizing the mode root D, and so on. Just be careful when substituting the 4th’s related natural minor scale in this way to emphasize the proper root note necessary to make the mode Phrygian). … In the key we’re using in this study – F Major, Phrygian mode could be identified and used over an Am to Bb (or A to Bb) chord change, to-wit: an A Phrygian mode scale.
For a good example of the unique sound of the Phrygian mode, listen to any of these jazz tunes: “Ole” by John Coltrane, “Sketches of Spain” by Miles Davis, or “Bemsha Swing,” by Thelonious Monk.
Advanced Theory: In the key of F major starting on the third degree – or A Phrygian scale … our chord progression viewing it as relating to F major would be iii (or sometimes III), IV, V, vi, viiÂ°, I, ii (and in chord progressions and songs constructed in all modes except Ionian or Locrian, the diatonic diminished chord is almost always skipped or another chord is substituted in it’s place in the progression). So an A Phrygian chordal progression (remember we’re in the key of F) would feature the following chords: Am (or A), Bb, C, Dm, (Em or E), F, Gm (or G) … So if you’re in a song where Am is the i chord, and you see/hear these other chords in this relationship to each other: i minor (or sometimes I Major), 1/2 step up to bII Major, bIII Major, iv minor, v minor (or vDim, or sometimes a V or V7 Major is substituted), bVI Major, bvii minor (or bVII Major, which is a common substitution) — think A Phrygian! … Also, in Phrygian mode, you could even see substitute Major chords for every chord in the progression, even the 4 chord – IV, although even where such Major substitution is done in Phrygian, the iv chord is usually always kept minor. … Remember, the most reliable indicator of the Phrygian mode will be the presence of a 1/2 step move from the i, or I, up to a bII.
The Lydian Mode, or fourth mode, is uniquely characterized by it’s #4 (or augmented 4th). The Lydian mode is often used where the I chord moves to II chord – and both are major. Particularly where the progression moves from the I chord to the II chord and repeats or cycles. (In fact, the presence of a II Major chord and/or movement from the I Major to II Major in the progression will often be the most identifying characteristic of the Lydian mode and distinguishes it from the Ionian mode or Major scale). The Lydian mode is also helpful where there is a 1/2 step change from a major I down to a minor vii chord (i.e. minor chord built on 7th degree of the underlying tonal/modal major scale). In this way, since we are talking about a half-step (one fret) chord change, it is similar to the Phrygian mode and other than the root being a half-step different, the fingerings are fairly identical. If we are in Bb Lydian, these chords would be Bb (I), C (II) and Am (vii). Additionally, a I – II – V (in Bb Lydian, that would be Bb, C, F) progression might also nicely support use of the Lydian mode well. Lydian mode progressions will tend to sound unresolved because of the #4 in the scale, and thus it is helpful to anchor the sound of the mode by using the root note of the mode as a drone/pedal tone or bass note for the other chords in your progression. For example, if we’re in Bb Lydian (constructed from F major) and the progression is moving from Bb to C and repeating or “cycling,” play the C chord as a Bb/C chord by adding a Bb as a bass note to the C chord to help anchor it to the root note of the mode. Because of the tendency for your ear to want to resolve to another chord when playing in Lydian, it is usually played against a drone/pedal tone and/or only for sections of a song.
For examples of the unique sound of the Lydian mode in the rock context listen to “Dreams” by Fleetwood Mac, which features a C Major scale against the F to G cycling progression producing F Lydian mode. Or you can also listen to, “Hey Jealousy” by the Gin Blossoms, “Flying in a Blue Dream” by Joe Satriani, “Hog Heaven” by Frank Zappa, “Jane Says” by Jane’s Addiction, “Just Remember I Love You” by Firefall, the intro & verses of “Here Comes My Girl” by Tom Petty, or the intro & verses of “Freewill” by Rush. Some very recognizable Lydian melodies are the very first few notes of the theme songs from The Simpson’s or The Jetsons cartoon shows, or the song “Maria” from West Side Story. Even “Oceans” by Pearl Jam may be yet another cool example featuring Lydian mode.
Advanced Theory: In the key of F major starting on the fourth degree – or Bb Lydian scale … our chord progression viewing it as relating to F major would be IV, V, vi, viiÂ°, I, ii, iii (and in chord progressions and songs constructed in all modes except Ionian or Locrian, the diatonic diminished chord is almost always skipped or another chord is substituted in it’s place in the progression). So a Bb Lydian chordal progression (remember we’re in the key of F) would feature the following chords: Bb, C, Dm, (Eb or Em), F, Gm, Am … So if you’re in a song where Bb is the I chord, and you see/hear these other chords in this relationship to each other: I Major (or Augmented), II Major, iii minor, minor #iv (or #ivDim, both built on the root 1/2 step below the root of the V chord, or a substituted Major IV 1/2 step above the iii – which is more commonly used in this mode), V Major, vi minor, vii minor — think Bb Lydian! … The most reliable indicators of Lydian mode will be Major I and a Major II chord, and almost always, the presence of a minor vii chord 1/2 step below the Major I chord.
(Note – there is also a fairly common & oft-used variation of the Lydian mode which involves not only #4 but also substituting a b7 for the 7 of the scale. Which is used as necessary to accommodate chords requiring this b7 note change, like, for example, where a Major bVII chord is substituted for the minor vii chord.. This common variation is called the Lydian b7 scale: http://gosk.com/scales/lydianb7-scale-for-guitar.php )
The Mixolydian Mode, or the fifth mode, will work over any Dominant 7th chord, since you’re merely flattening the 7th degree of the major scale associated with that chord to accommodate the b7 necessary to the Dom7 chord. Further, mixolydian is often used where the progression moves from a major chord to the major chord a whole step (two frets below it) … for example, where the progression moves from I to bVII to I to bVII and cycles back & forth – you get the idea. It’s also used in folk or country progressions (or rock or blues) where the progression immediately moves from the I chord to the V chord particularly where there is also a IV chord in the progression – this is due to the mode being built on the major key of the V chord and there being a whole-step move down to the IV chord, characteristic of the I to bVII movement of this mode.
For a good example of the unique sound of the mixolydian mode, listen to The Grateful Dead’s “Fire on the Mountain” which moves from B to A to B to A -or- I bVII I bVII and is played in E Mixolydian – which you might also view as a V to IV progression in E Major. Other Mixolydian examples include a traditional folk tune “Old Joe Clark,” “No Rain” by Blind Melon, “I’m So Glad” by Cream, the jazz standard “On Broadway” by George Benson, the main riff from “Third Stone From The Sun” by Jimi Hendrix, “1999” by Prince, “Cinnamon Girl“ by Neil Young, “Cult of Personality” by Living Colour, “Franklin’s Tower” by the Grateful Dead, “Jessica” by the Allman Brothers Band, “Lowrider” by War, “Free” by Phish, “Get Down Tonight” by KC & the Sunshine Band, “Louie, Louie” by the Kingsman, “Possum Kingdom” by the Toadies, “What I Got” and “Wrong Way” by Sublime, “What I Like About You” by the Romantics, “Dear Prudence” by the Beatles, the intro & verse sections of “Norwegian Wood” by the Beatles, or even the verse section of “Tequila” by The Champs.
Advanced Theory: In the key of F major starting on the fifth degree – or C Mixolydian scale … our chord progression viewing it as relating to F major would be V, vi, viiÂ°, I, ii, iii, IV (and in chord progressions and songs constructed in all modes except Ionian or Locrian, the diatonic diminished chord is almost always skipped or another chord is substituted in it’s place in the progression). So a C Mixolydian chordal progression (remember we’re in the key of F) would feature the following chords: C, Dm, (Em or E), F, Gm (or G substitution – more likely), Am,Bb, … So if you’re in a song where C is the I chord, and you see/hear these other chords in this relationship to each other: I Major, ii minor, iii minor (or iiiDim, or even a III Major), IV Major, v minor or V Major (a Major V is almost always substituted in Mixolydian mode!), vi minor, bVII Major — think C Mixolydian! … The most reliable indicator of Mixolydian mode will be the presence of the Major bVII chord a whole-step below the Major I chord, coupled with the presence of a Major IV chord.
The Aeolian Mode, or sixth mode, is the exact same thing as the natural minor scale! For any major scale, find it’s sixth degree, and build a natural minor scale over it (1, 2, b3, 4, 5, b6, b7) & you get the Aeolian mode. Any song which features a i iv v, like a minor blues or rock progression using the i iv v, can be played in the Aeolian mode. You might also see a V7, or a bIII, bVI, or bVII chord in songs in this mode. Certainly, any song which moves from the minor i to minor iv is most likely in Aeolian mode & will sound good against the natural minor scale.
For a good example of songs featuring the Aeolian Mode, listen to the guitar solo in Led Zeppelin’s “Stairway to Heaven” or “Achilles Last Stand,” or any variety of minor blues or rock songs using all minor chords for the i iv & v – note sometimes a Major V or V7 is substituted for songs in this mode, but the minor i to minor iv change will give it away. You can also listen to these classic songs: “All Along the Watchtower” by Bob Dylan or Jimi Hendrix, “Black Magic Woman” by Fleetwood Mac or Santana, “Maria, Maria” by Santana, “Building A Mystery” by Sara McLachlan, “Rhiannon” by Fleetwood Mac, “You Give Love a Bad Name” by Bon Jovi, “Mr. Jones” by the Counting Crows, “Two Step” by the Dave Matthews Band, “Thank You” by Dido, the main riff to “Nothing Else Matters” by Metallica, “Crazy Train” by Ozzy Osbourne, “Paranoid” by Black Sabbath, “Buddy Holly” and “Hash Pipe” by Weezer, “Last Resort” by Papa Roach, “First Tube” by Phish, “ATWA” by System of a Down, “Schism” by Tool, “Sultans of Swing” by Dire Straits, “Sweet Dreams” by the Eurythmics or Marilyn Manson, and Nirvana’s “Smells Like Teen Spirit, which uses power chords derived from the Aeolian mode.
Advanced Theory: In the key of F major starting on the sixth degree – or D Aeolian scale … our chord progression would be vi, viiÂ°, I, ii, iii, IV, V (and in chord progressions and songs constructed in all modes except Ionian or Locrian, the diatonic diminished chord is almost always skipped or another chord is substituted in it’s place in the progression, although in blues songs in this mode you will sometimes see a iiÂ° chord). So D Aeolian chordal progression (remember we’re in the key of F) would feature the following chords: Dm, (Em or E), F, Gm, Am (or A), Bb, C, … So if you’re in a song where Dm is the i chord, and you see/hear these other chords in this relationship to each other: i minor, ii minor (or iiDim, or even a II Major), bIII Major, iv minor, v minor (sometimes the V Major or V7 Dominant is substituted), bVI Major, bVII Major — think D Aeolian! …The most reliable indicators of Aeolian mode will be the presence of both a Major bVI and Major bVII below the minor i chord, & a particularly tell-tale identifying giveaway will be the presence of a minor iv chord.
Finally, the Locrian Mode, or seventh mode, will be immediately identified by the presence of a diminished chord at the root or heart of the progression. This mode is based on the root of the diminished chord. Consequently, it has a very exotic sound. Some might describe it as a Japanese or even Hindu type flavor. This mode is not generally used for song construction, but there are rare examples. You will most likely encounter it for a short passage or progression, or more often when it is used to emphasize a diminished chord.
Frankly, there just aren’t many songs in Western music written entirely in the Locrian mode, but if you’re a masochist, you could listen to the march from Three Fantastic Dances by Dmitri Shostakovich, which is one of the rare examples of a whole piece written in mainly Locrian mode. You will hear this mode used over diminished chords & diminished jazz progressions.
Advanced Theory: In the key of F major starting on the seventh degree – or E Locrian scale … our chord progression would be viiÂ°, I, ii, iii, IV, V, vi. So E Locrian chordal progression (remember we’re in the key of F) would feature the following chords: E(dim), F, Gm, Am, Bb, C, Dm, … So if you’re in a song where E(dim) is the iÂ° chord, and you see/hear these other chords in this relationship to each other: i(dim), 1/2 step up to bII Major, biii minor, iv minor, bV Major, bVI Major, bvii minor — think E Locrian! … The most reliable indicator of Locrian mode will be a diminished i chord and/or the very noticeable diminished sound of the song or progression.
(Advanced Diminished Theory Note — there is one more 7th degree root mode mode which is commonly used in jazz – the “Super-Locrian Mode.” A Locrian scale has everything flattened but the root 1 & the 4th. The formula is 1 b2 b3 4 b5 b6 b7. However, the Super Locrian mode scale, goes one more, and also flattens the 4th: 1 b2 b3 b4 b5 b6 b7. The Super Locrian is also called the jazz scale, or altered scale, or diminished whole tone scale. Super Locrian is the “offical” name of the 7th mode of the melodic minor scale. It is called the altered scale because it contains the most important jazz alterations (b5, #5, b9, #9) used with altered dominant chords. Since it has all those alterations, it is frequently used over altered dominants, hence it’s shortened name – the Altered scale. A quick look at the way it lines up will give you an idea of why it is also referred to as the diminished whole tone scale.
As my friend bassist Kelly Tomlinson, who majored in music theory, describes: In standard four-part harmony, the vii7 chord is half diminished if it stays in the key, and it usually does, unless it’s being used as a pivot chord to change keys. Then it’s a fully diminished chord that utilizes the flat submediant (i.e. a b4). That diminished chord utilizing a flat submediant (b4) built on the major 7th degree of the original key/scale can then become the leading tone into a substitute V7 of the new key built on the major 2nd degree of the original key/scale – i.e., the 5th degree of the new key/scale – and resolve nicely to change keys in the middle of the song down a minor third, or up a minor third if the process is reversed moving from the V7 chord of the original key/scale to a diminished chord built on the 2nd degree of the original key/scale to the I or i of the new key/scale. This process of using the diminished chord to change keys up or down a minor third works over both Major or minor keys. Consequently, when soloing over diminished chords of all varieties, rather than concentrate on the Locrian modal scale, which has a tritone as its own tonic and dominant rendering it atonal, it’s just best to know where to end up next! All the theory in the world won’t save that trainwreck!)
Final Thought: Practical Tips on When & How to Combine Modes
In deciding which mode to use, you should always start with the scale or mode which best fits and includes all of, or at least the most, notes from the chords in the song or progression and which best suits the mood of the song or the mood you’re trying to create. You might first start by remembering that one of the three Major modes – Ionian, Lydian & Mixolydian – will likely work better as a choice to play over an entire Major key progression or song, whereas one of the three minor modes – Aeolian, Dorian & Phrygian – will likely work better as a choice to play over an entire minor key progression or song. The reality, however, is that unless you’re dealing with a fairly simple chord progression or one which exclusively uses diatonic chords all built only from the notes of one underlying key, then you are going to have to make adjustments as necessary to pick up chord tones which are “outside” the notes/tones of the modal scale you initially choose. You might simply adjust your modal scale to pick up any outside notes over the outside chord when it appears in your progression or by choosing to play a different mode, or arpeggio, which better fits the outside chord when it comes up. And remember you can always bend up to chord tones, or use chromatic notes to walk or slide up or down into any chord or scale tones, to make things even more interesting. There are many times, like in using both minor and major pentatonic scales together over a blues progression, where you may want to combine modal scales.* This article is designed merely to give you a good idea how & where to start.
(* Advanced Theory Note on Combining Modes — Let’s take a typical Dorian progression with a minor i chord and a Major IV chord, like Gm to C. While using a G Dorian modal scale will work over both modes, sometimes it’s even more pleasing to use the G Aeolian mode over the Gm half of the progression emphasizing the b6 of the G natural minor scale, but switching to G Dorian mode (i.e. raising the 6th) over the C (IV) chord to emphasize the Major 3rd of the C chord. If the progression moves to a Dm for the v chord, G Dorian will continue to work, but so would G Aeolian, since both of those modes also contain all of the notes of Dm (D F A) in their scale. Another way to look at it is that diatonic chords of G Dorian and G Aeolian modes contain a minor v chord (Dm). … If instead, the V chord is D Major, neither the diatonic G Dorian or G Aeolian modes fit since D contains an F# in it’s construction [D F# A]. Well, we could just use an D Ionian modal scale – D Major scale – over the D chord, but that takes our minor sounding progression and temporarily makes it sound Major and, in this case, not in a good way! So instead we might try to find a minor sounding mode that also works. A Aeolian contains an F or b6, not an F# 6, so that won’t work particularly well. However, an A Dorian scale would raise that 6th from minor b6 to Major 6 and catch the F#, but it also contains a b7 (G), which is the root note of both our G Aeolian and G Dorian modal scales that we have found to be very pleasing and better fit the “mood” of our progression. [And here’s another helpful hint: as in our example, it’s actually a very common technique to simply move the very same type same modal scale being used over the 4 chord up a whole-step when playing over the 5 chord – particularly where both chords are Major; as in our example, moving G Dorian over the IV chord up to play A Dorian over the V chord].
Another example of a very common combination of modes is to mix and match licks from C Mixolydian (built from our F Major scale) with C Dorian (built from a Bb Major scale) over a I bVII IV progression in C, i.e., C Bb F. The reason this works is that both of these modal scales, despite being constructed from different parent Major scales, contain all of the triad notes for all three of those chords. Combining Mixolydian and Dorian modes constructed from the same root note in this way works well over any I bVII IV, or I IV bVII, progression.
Finally, since you can use mixolydian mode over any Dom7 chord, it works particularly well to spice up a standard 1 4 5 blues progression which uses all Dom 7 chords – e.g., F7 (I), Bb7 (IV), and C7 (V). We would play F mixolydian over the F7 chord (the fifth mode constructed in Bb Major), Bb mixolydian over the Bb7 chord (the fifth mode constructed in Eb Major), and C mixolydian over the C7 chord (the fifth mode constructed in F Major). So we play the mixolydian mode starting on the root note of the chord over each of our Dominant 7 chords to emphasize the b7 note in the chord. Try it on your blues, you’ll like it!
Remember, the point here is that in choosing which modes to use when combining modes, it’s usually best try to pick ones that either both contain all the notes from all the chords in the progression, or where that’s not possible, and it becomes necessary to choose a different mode to accommodate an “outside” chord tone/note, try to select a mode to play over the “outside” chord which at least creates the same “mood” over the progression being played, e.g., that keeps the same overall all minor, or all Major, modality of the song or progression, … unless you’re purposefully trying to add a tasteful and pleasant sounding touch of Major over an otherwise minor song or progression, or vice-versa, … purposefully incorporating a blues note or an “outside” note to add pleasing color or to create chromatic or other tension to resolve back into a chord tone or to create/follow the unique melody of the song, … or purposefully changing the overall minor v. Major modality entirely to support a new key change or new progression intentionally written to create a completely different mood – as sometimes done in a bridge or chorus, or underneath a solo to make it more interesting.)
I hope this explanation was fairly easy to understand & helpful. Maybe it will inspire you to start spicing up your improvisation and soloing by starting to include modal concepts into your playing or help you more quickly identify which modes might work over the chord progressions being thrown at you on stage. Anyway, have fun, practice hard, & perform like a pro!
© Beth Isbell 2010