Two-Part Writing & Independence
Writing one strong melody is hard enough. Writing two that stay independent of each other — and still sound good together — is the next challenge.
What "independence" means
When combining two melodic lines, the goal is independence: each voice should be strong enough to work as its own melody, and the two together shouldn't collapse into what sounds like a single thickened line. That independence comes largely down to how the two voices move relative to each other.
Contrary and oblique motion
Two voices can move in three basic ways. In contrary motion, they move in opposite directions — one rises while the other falls. In oblique motion, one voice holds a note while the other moves around it. Both keep the ear tracking two distinct lines. In parallel motion, both voices move the same direction by the same interval — usable in moderation, but risky in one specific way.
Why parallel 5ths and octaves are avoided
When two voices move in parallel perfect 5ths or octaves, their pitches lock together so rigidly that the ear stops perceiving two independent lines and starts hearing one line, doubled. Since the entire point of two-part writing is having two voices, this specific parallel motion is avoided — it undermines the texture you're trying to create.
Common questions
What does "voice independence" mean in two-part writing?
Each melodic line is strong enough to stand alone, and the two lines move in ways that keep them sounding like separate voices rather than one thick line.
What is contrary motion?
Two voices moving in opposite directions — one rises while the other falls. It's the strongest way to keep two lines independent.
What is oblique motion?
One voice holds a note while the other moves. It preserves independence since only one line is active at a time.
Why avoid parallel perfect 5ths and octaves?
They lock the two voices' pitches together so tightly that the ear hears one thickened line instead of two independent ones.
Layer two lines and hear them together
Melody Monkey's Songwriting Studio lets you stack a melody and countermelody and hear exactly how they interact.
Open the free app →Still stuck? Ask Your Personal Music Teacher about Two-Part Writing & Independence →