The ascending perfect fourth interval has a very strong harmonic implication that can be useful for both composers and jazz improvisers (as well as being good exercises for technique development). The perfect fourth interval has the sound of a V-I (authentic) cadence. This sound is so ingrained in western music that even without any other pitches sounding we can hear the cadence when it’s set up right. Additionally, stacking perfect fourth intervals together create a characteristic sound when used to voice out chords. One of my old teachers, Frank Mantooth, was the first person to introduce me to this concept. Voicings with only perfect fourths can imply a number of different chords, depending on what bass note sounds at the same time.
The above voicing could be used for an F69 chord (containing the root, 5th, 9th, 6th, and 3rd), a Bbmaj9 chord (5th, 9th, 6th, 3rd, and 7th), a Dmin11 chord (3rd, 7th, 11th, root, and 5th), a G7sus (7th, sus 4th, root, 5th, and 9th), and even some others. Mantooth referred to this style of piano voicing as “miracle voicings” because they allow the pianist to play so many different chords without changing any pitches.
A couple of days ago while warming up for the Paul Whiteman Tribute concert I was talking with trumpet player Rich Willey about patterns based on the interval of a perfect fourth and Rich hipped me to an approach he uses to accent different pitches while still playing patterns that utilize only the interval of an ascending perfect fourth (and its inversion, the descending perfect fifth). By altering where to change the direction the ear will pick up on those changes of melodic direction and those pitches will sound more prominently in the pattern.
The above example can be described as perfect fourths in the rhythmic pattern of 2. In other words, after two pitches the pattern changes and descends before repeating again. This change of direction makes the downbeats in this particular example stand out (C, Bb, Ab, F#, etc.). Isolating just those pitches will form a descending whole tone scale (C, Bb, Ab, F#, E, D, C).
This next example contains perfect fourths in the rhythmic pattern of 3.
If we isolate the pitches that fall on the change of direction we end up with the pitches C, Eb, F#, A, and back to C. These pitches together make up a fully diminished 7th chord.
Playing perfect fourths in a rhythmic pattern of 4 will get yet another sound.
This pattern will emphasize the pitches of C, Ab, and E, forming an augmented triad. This particular example may get a little rangy for some instrumentalists. If we continue to expand on the same intervals with the rhythmic pattern of 5 pitches before changing direction we end up with a lick that ends up with a range that might be too wide a range for many horn players.
The pitches that get emphasized here include C, Db, and D. If we were to continue this pattern further it would emphasize all the pitches of a chromatic scale. Rich showed me how he deals with the range by instead utilizing a rhythmic pattern of 3 plus 2.
Playing the perfect fourths pattern in this way ends up emphasizing the same chromatic scale sound, but also emphasizes an additional pitch in the pattern. In the above example the pitches C, Eb, Db, E, D, F, Eb, F#, and E. Isolating just those pitches creates a rising minor third followed by a descending major second. Reorganizing those pitches so that they just ascend ends up creating a diminished scale (half step, whole step, half step, whole step, etc.).
Flipping the pattern to 2 plus 3 similarly will bring out the pitches of a diminished scale, but instead with a descending interval of a major second followed by the ascending minor third (C, Bb, Db, B, D, C, Eb, Db, E).
By now the concept of playing the exacts same pitches, but changing the direction of the line in different rhythmic patterns should be clear enough to suggest further ideas for exploration, including mixing up some of the above patterns into the same line. Because of the strong harmonic implication from the perfect fourth interval as well as the different sounds brought out by changing the melodic direction patterns such as this can provide a method for improvisers to take their lines “outside” the changes while still implying a chord progression. Since playing nothing but perfect fourths moves through all twelve pitches it’s easy to resolve these lines back inside by simply stopping the pattern on an appropriate chord tone or by releasing the tension of a non-chord tone with a step-wise resolution.
There are lots of different approaches to how to effectively use intervals like the perfect fourth in a musical and expressive way. Try playing around with these patterns for a bit and see what you think. If you come up with another pattern or approach to applying intervals you’d like to share either contact me or leave a comment below.