The Major 7 arpeggio (1 3 5 7) has many uses; it can be superimposed over harmonies in all kinds of ways and I use it a lot. If you flatten the fifth (1 3 b5 7) you get a new sound with different applications. Here I'll talk about some of the possibilities.

First, here are CAGED diagrams for the Maj7b5 arpeggio, taken from Arpeggio and Scale Resources:

If you play through them you'll probably find they present some quite awkward technical challenges; I've therefore produced some tabbed-out fingerings with suggested fretting-hand finger choices (the small numbers) and picking directions (for the first position only).

OK, that's the preliminaries dealt with: how do we start using this thing to make music in the context of triad-based harmonies? Clearly we can play it over a Major 7 chord with a flattened fifth, but that doesn't come up very often, so we're looking for ways to superimpose this arpeggio over some other chord that will sound good.

As with anything else, over a harmony with a given root note there are twelve possible Maj7b5 arpeggios we can play: the one built off the root, the one built off the b2, the one built off the 2 and so on. We can look at these in a table but that's not usually very enlightening. So how do we get started?

Major-Scale-Modal Applications

One way is to notice that the Maj7b5 arpeggio (1 3 b5 7) can be respelled (1 3 #4 7), which are all notes from the Lydian scale. In fact, looked at this way it's kind of the distilled essence of the Lydian sound -- a major 7 arpeggio (minus the not-usually-interesting fifth) plus that #11 that makes Lydian what it is.

So a good start on those twelve applications is to use the Maj7b5 at the root as a substitute for the Lydian scale. Over CMaj7 play CMaj7b5 and you're off. Not wonderfully exciting, but this is one out of the twelve possibilities covered off, and you may enjoy the different lines you tend to create. You can mix in other Lydian scale notes, too.

This gives us an idea: if it works for Lydian, it should work for the other six Major Scale modes as well. For example, it turns out that if over a Cm7 chord I play DbMaj7b5, I get the notes Db, F, G and C; these are four of the seven notes in the Phrygian scale. If I want a Phrygian sound but I don't just want to run the scale, I can use this arpeggio instead to give me some more tasty intervallic choices without introducing any new notes.

Here's a quick table of which Maj7b5 to play over a chord to get notes from the given mode:

Major Scale mode Arpeggio to use Most obvious chordal application Ionian IV Maj7b5 Maj7 Dorian bIII Maj7b5 m7 Phrygian bII Maj7b5 m7 Lydian I Maj7b5 Maj7 Mixolydian bVII Maj7b5 dom7 Aeolian bVI Maj7b5 m7 Locrian bV Maj7b5 m7b5

These are actually not so hard to remember: in many cases the note you use to build the Maj7b5 arp is one of the characteristic notes in the scale. Learning these applications is a good way to internalise the arpeggio shapes and their sounds without stretching your ears too much at the beginning. Relating a new resource to something familiar is always a nice way to start.

Melodic and Harmonic Minor Modes

I tried to find common scales (or modes of them) that relate to these applications the way the Major Scale modes related to the ones in the previous section, but these are quite hard to spot by eye (try it!). Here the technique I call "spectral analysis" is useful, because it takes the guesswork out of the process. Here, for example, is the 7-spectrum of the Maj7b5 arpeggio, take from my book Spectral Analysis of Scales

All these 7-note scales contain, somewhere within them, the Maj7b5 arpeggio. And since that accounts for four of their notes, to learn each scale we need only learn how to add another 3 notes to it. Most of these are very exotic indeed, but in the list we can see both Harmonic and Melodic Minor scales. How does the arp fit these modes? A bit of calculation gives us this table:

Root note of arpeggio Harmonic Minor mode Melodic Minor mode Major Scale mode I Lydian #2 Lydian Augmented Lydian bII Phrygian Dominant Dorian b2 Phrygian II bIII Dorian #4 Melodic Minor Dorian III Super Locrian IV Ionian #5 Major bV Locrian Natural 6 Half-Diminished Locrian V bVI Harmonic Minor Mixolydian b6 Aeolian VI Super Locrian bb7 bVII Lydian Dominant Mixolydian VII

This gives us a way to start expanding our Maj7b5 vocabulary beyond the sounds of the Major Scale modes. There's already a lot to work with here, and even if you know your Harmonic and Melodic Minor modes fairly well I'm willing to bet you'll find something new here.

Notice, too, that the table now has at least one entry for all but three of the rows; in other words, we can "make sense of" all but three of the Maj7b5 superimpositions by thinking of them in terms of one or more fairly common 7-note scales.

More Exotic Heptatonic Scales

This is all very well, but what about all those other scales in the list? The next ones that jump out for me are probably Neapolitan, Double Harmonic and Senavati, all scales I use fairly often but could always have a better knowledge of. It doesn't take long to find the modes of these scales that contain Maj7b5 arpeggios. This can be a good way to learn one of these scales, especially if the sound of the mode isn't familiar to you. This is a particular problem with the Neapolitan which, because it's "almost symmetrical", has modes that can sound very similar to each other.

Here's the table for the twelve superimpositions as they relate to modes of these three scales (you'll probably need to refer to Arpeggio and Scale Resources for spellings and diagrams):

Root note of arpeggio Double Harmonic mode Neapolitan mode Senavati mode I Rasikapriya Lydian Aug #6 Latangi

Superaugmented nat 3 bII Double Harmonic Neapolitan Senavati

Ionian b2 II Kanakangi b5 Super Locrian bb3 Locrian bb3

bIII III Super Locrian b2 Aeolian b4

Superaugmented nat 3 IV Augmented #9 Ionian b2

bV Chakravakam b5 Charukesi b5 Mixolydian b5

Locrian bb3 V bVI Simhendramadhyamam Rishabhapriya Latangi

Aeolian b4 VI Senavati b4 Senavati

bVII Lydian Dominant #5 Mixolydian b5

VII

Well, there's a lot here to work on as well. Some of the superimpositions are shared by a pair of Senavati modes, which is interesting if (like me) you enjoy this scale, and notice that now we have all but two of the superimpositions covered by one or other of our scale options. The V and VII are still eluding us -- to cover these off we'd have to go to even more exotic scales, but this is quite enough material to make me feel dizzy already.

Practicalities

OK, so how can we approach this stuff? It seems to me there are two main ways: horizontally or vertically. In both cases you want to pick a single superimposition of the Maj7b5 and learn to "hear" it in relation to a larger scale that contains it.

Say we pick the one at the bII for argument's sake. We know this is contained in Phrygian, so we can noodle around with notes from the Phrygian, scale to fill out the sound, maybe over a nice minor 7 vamp backing track to help us hear how it goes. So over a Cm7 backing we'll play DbMaj7b5, and switch in notes from C Phrygian when we feel like it.

The vertical approach is the one I take if I want to learn as many different superimpositions of the Maj7b5 as I can. I pick a column -- probably starting with familiar ones like the major scale modes -- and work my way down it. So over my C-rooted backing I'll play CMaj7b5 interspersed with Lydian, DbMaj7b5 interspersed with Phrygian and so on. This will give a good handle on how the arp sounds in different positions relative to the root note, and is a good place to start if your goal is to internalise the sound of this little group of intervals.

The horizontal approach is more about working with different scales in the context of a single superimposition. So over that C root we can stick with DbMaj7b5 but intersperse it with Phrygian, then Phrygian Dominant, then Dorian b2, then Double Harmonic and so on if you want to get more exotic. This should give you an idea of the many sonic possibilities offered by just one single superimposition.

I'd advise most people to take a sort of compromise approach, looking maybe at a specific chord quality (like minor 7) and working with all the vertical options that make sense on that chord and all the horizontal ones you already know. Later you can, if you with, add more horizontal ones you don't yet know as a way to learn them.

And all that should give you enough to work on for the next twelve months if that's what you want. More likely you'll take something from playing around with all this and make it your own; that's fine too, of course.