Quick and Easy Theory Lesson – Playing with 9ths

Article By Sean Christiansen – Founder of the Rock N Blues Guitar Academy

Easy Theory for Guitar Applications – Playing with Ninth Intervals

When most guitarists solo they start on the root, or the same note as the Key the song is in. It’s a nice compact way of looking at things, and starting your guitar solo. But after a while, we can begin to dumb down sonically, from always beginning on the same note.

Today I want to share a very easy idea to open up your ears a little bit, using theory, but in a way that isn’t boring or complicated. Starting your lead playing on the 9th interval.

The origin of this probably has its roots in Jazz where guitarists have learned to exploit their understanding of music and shape it any way they wish. In the end, its about creating harmonic tension and release and in doing so, adding interest to the guitar, both in what a particular note leads to for the guitar player, and also, in what the listener hears that bends the ear a bit.

It is not the purpose or scope of this article to explain the whole musical theory behind what an interval is, or how they are derived, those things along with an entire series of effortless mastery of tension and release ideas and approaches can be found on my site, www.rnbacademy.com where I have created an entire system designed to create self-sufficient guitarists, that I’ve been teaching for years.

Rather, this is a fast and “dirty” idea to supercharge your playing, with no background needed.

For our purposes, lets assume that you know you are soloing in A minor, and as usual you start the solo on the A note. How do we find the 9th? And why is the 9th such a good idea.

For one, the 9th is universal regardless of the chord type. A 9th is the same note every time whether its a Major 9, Minor 9, add9 or Dominant 9th chord. You can even play a 9th when there isn’t a 9th in the chord itself.

For another, the note adds a certain…beauty in its tension. It doesn’t quite fit, but somehow it also feels like a note that has a certain melodic quality that feels right. Jazz greats like Larry Carlton and Robben Ford use this note and use it a lot to exploit this inner beauty.

So without the theory part of this bogging things down, and now that we agree that the 9th is a pretty cool note, how do we use it? Where is this sweet interval found when I want to conjure up that sweet sound that may lead the ear to some interesting melodic ideas as I solo?

The answer – Its one step (2 frets away) from the root!

Now I hear you, you’re already convinced that something’s off here, and ready to throw in the towel and say, “wait a minute, that doesn’t sound all that awesome.” But that’s just the beginning step to locate the 9th. To really hear the sound of the ninth, move that note up an octave and start your lead there!

See the below illustration in G – G is the Key, and I want to start my lead on the 9th. A Is a whole step up from G and moved an octave away, A becomes my 9th.

music theory lesson fretboard diagram of playing in 9th intervals

A 9th interval as found on a guitar fretboard

Note that you can really start the 9th a step away from the root note, but its pitch to the root will be more effective, if it’s an octave or more higher than the root.

For theory buffs (those who have a bit of their music theory basics down, read ahead, and those who don’t, may wish to skip this part and check out our lessons site, or simply stop here and go play and start using your 9ths):

A 9th is basically a 2nd moved up an octave, this is known as a compound interval. Anything father than an octave (8) from the root (1) becomes a compound interval, thus 9ths are compound. So are 11ths and 13ths.

The ninth wants to pull two places to feel centered or resolved in the melody: the root, which is its most stable note, creating zero tension, or else the 3rd (depending on whether its a major type or minor type progression, this may be a different note). The little bit of musical tension and interest that the 9th can create musically can be an effective idea spawner and rut buster, and while no music theory is needed to start to use this idea in your own playing, a sold musical theory based in guitar application program, like we teach, can reap huge dividends for guitarists wanting to go to the next level. For more information, check out our courses at www.rnbacademy.com

In a future article, we will look at how 11th intervals can be used, and understood, (as well as explore ways they are often misused) to create additional harmonic interest!