There is nothing more frustrating for a choir director than ending a piece a semitone lower than where it started. "Sinking pitch" is the common cold of choral music: it affects everyone, spreads quickly, and feels impossible to cure. Many directors blame "lack of energy" or "tired singers." They wave their arms higher, hoping the pitch will rise. It rarely works. Why? Because intonation is not about energy. It is not about magic. It is about physics. If you understand the acoustic laws that govern sound waves, you can fix pitch problems with a screwdriver instead of a prayer.
Part 1: The Piano is a Lie
Most singers grow up singing along to a piano. The problem? The piano is technically out of tune. It uses a system called Equal Temperament. In this system, every half-step is exactly the same size so you can play in any key (C Major or F# Major) without it sounding terrible. But the human voice (and the physics of sound) prefers Just Intonation—tuning based on the natural harmonic series.
The Major Third Problem
This is the single biggest cause of choral dissonance.
- The Physics: In nature (Just Intonation), a Major Third (e.g., C to E) represents a frequency ratio of 5:4. It is a sweet, pure, smaller interval.
- The Piano: In Equal Temperament, the Major Third is tuned sharp (about 14 cents sharp) to make the math work.
- The Result: If a choir sings a "Piano E" on top of a "Piano C," the chord will sound harsh, gritty, and "beaty." The sound waves are clashing.
- The Fix: To make a chord "ring" or "lock," the Third must be tuned lower than the piano. Singers must be taught to "settle" into the chord, not reach for the high note.
Pro Tip: If you have perfect pitch, you are at a disadvantage here. You are trained to hear the "Piano Pitch" as correct. You must retrain your ears to hear the "Physics Pitch."
Golden Rule: Sharp Leading Tones (Ti -> Do). Flat Major Thirds (Do -> Mi).
Part 2: The Perfect Fifth (The Anchor)
While Major Thirds are flexible, Perfect Fifths (C to G) are non-negotiable. They must be pure. A pure fifth has a ratio of 3:2. It is incredibly stable.
- The Danger: If the Fifth is even slightly flat, the chord loses its "ceiling." The root and fifth provide the acoustic "room" for the third to live in.
- The Exercise: Tune the outer intervals first (Root and Fifth). Only when they are locked (no wobbling beats) should the middle voices (Thirds) be added.
Part 3: Why Choirs "Sink" (The 4 Culprits)
1. The Gravity of Descending Lines
It is a law of nature: what goes up must come down. When singers descend a scale (Do-Ti-La-So), they tend to relax their breath support too much between notes.
- The Psychology: Singers think "Down means relax."
- The Fix: Think "Up" while singing "Down." Visualize walking down a staircase, not sliding down a slide. Add more energy to the bottom notes.
2. The Vowel Clash
If the Sopranos are singing "Ah" (bright) and the Altos are singing "Uh" (dark), the acoustic waves physically clash. The choir subconsciously tries to find a middle ground, usually dragging the pitch down.
- The Fix: Match vowel shapes instantly. Use "Tall Vowels" (dropped jaw) rather than "Wide Vowels" (spread lips). A unified vowel creates a unified pitch.
3. The "Commas" Trap
This is advanced, but common. In a piece that modulates frequently, the "math" of Just Intonation can actually drive the pitch down over time (this is called the Syntonic Comma).
- The Fix: Sometimes, you just have to cheat. Mark specific notes (usually the new tonic) with an "Up Arrow" to reset the pitch center.
4. Repeated Notes
When a singer repeats the same pitch (C - C - C), they almost always go flat on the repetitions.
- The Visualization: Imagine the pitch is not a flat line, but a slightly rising staircase. Aim each repeated note slightly higher than the last.
Part 4: Practical Exercises to Lock the Chord
Exercise 1: The Drone Challenge
Have the Basses hold a steady drone (Root). Have the Sopranos slowly sing a descending scale against it.
- Goal: Listen for the "beats" (wobbles) in the sound. Adjust the pitch until the beats stop and the interval becomes pure. This teaches singers to tune properly vertically (to the harmony) rather than just horizontally (to the melody).
Exercise 2: Ghost Singing
- Sing the first phrase of a song aloud.
- "Ghost" (silently audiate) the second phrase.
- Sing the third phrase aloud.
- The Test: Did the choir come back in exactly on pitch? This forces mental engagement. Most pitch problems happen because the brain turns off during rests.
Exercise 3: Vowel Tuning
Sing a chord. Have the director change the vowel with a hand sign (Ah -> Oh -> Ee).
- Goal: Maintain the exact same pitch center while changing the shape of the mouth. Often, moving to "Ee" makes people sharp, and "Oh" makes them flat.
Video Tutorial: The Science of Tuning
This demonstration visualizes exactly what happens to sound waves when intonation locks. Watch how the waveforms align.
Final Thoughts
Perfect intonation isn't about straining to be "high enough." It's about listening to the physics of the chord and finding the pocket where the sound rings freely. When a chord is perfectly tuned, it actually sounds louder, because the overtones are constructive rather than destructive. It is the ultimate free energy.
Intonation is just one part of the puzzle. Next, we analyze the genius of modern harmony in Jacob Collier's Harmonies Explained.
About the Author
HaND. is a choral veteran with 15 years of experience in practice and organization. A primary Bass, HaND. also demonstrates exceptional versatility as a Countertenor and Vocal Percussionist.
