Second Relations: The root of any second relation progression is uncertain. Unlike a third relation, chord quality does not always change from chord to chord in a second relation.
Unlike fifth and third relations, the second relation has no common tones. Thus, every chord tone must move to the next chord, making the second relation the most melodically active of all chord progressions.
This hypothesis can be tested by repeatedly hearing and performing melodic major and minor seconds up and down. The aim of such a test is to decide which of the two tones is a better destination note.
Example 4: Effect Of Second Relations
Compare the effects in examples 2, 3 and 4. Listen carefully for harmonic closure, color, and linear effects.