The 7th is, by itself, a rather disssonant or harsh interval when played together by it’s lonesome. There are two types of 7th’s – major (11 half steps) or minor (10 half steps).
In a major key, the 7th is major (as are all the non-perfect intervals in a major key from the root). So if we look at the key of G:
G A B C D E F#
M2 M3 P4 P5 M6 M7
Try playing G to F# and you’ll hear dissonance, or vibration occuring between the two notes. Now, play a Gmaj 7 chord:
G B D F#
and you’ll find it pleasant sounding. The other notes of the chord tend to smooth out the sound and leave the chord sounding rich, rather than harsh. This adds a complexity to the sound which is why the major 7 chord is rarely played with distortion – it amplifies the tension in the chord and makes it too harsh.
If you invert these two notes, that is play F# up to G rather than G up to F#, you’ll find it quite harsh. Remember, in a chord voicing, any arrangement of the notes is fair game. You can jumple up the 4 notes of Gmaj7 anyway you want, it’s still a Gmaj 7
The minor seventh is found in minor 7 and dominant 7 chords. It’s not as harsh a sound, but definitely worth playing in your solos against these chords.
If you play with 7ths, you’ll most likey have to skip a string, which I think is a good thing. Most guitarists don’t play like that enough. It takes some practice, especially with the picking hand, but there’s no reason why not to. Remember, when you learn new things, you leave your comfort zone behind until this too becomes comfortable.
As the dominant 7th is used in blues a lot, I like to bend from the 6th of the chord to the 7th. So in A blues, on A7 I would play F# and bend a half step to G (2nd string, 7th fret) and probably resolve that down to the 5th of the chord, E (2nd string 5th fret).
One of the way of really getting to know where the 7ths are as you go up the neck is to be famliar with the triads, or chord shapes up the neck, which I’ll cover in a future blog.
Have fun with the 7ths and don’t be afraid of skipping a string – just practice everyday for a week and you’ll be surprised how easy it is and how you won’t sound like everybody else 🙂
Next blog: P8 or Octaves