Part Writing Calculator
Analyze your SATB chord voicings for common errors in real-time.
Visual Staff Representation
Notes will appear on the staff as you select them.
Analysis Results
Select notes for each voice to check for part writing errors.
What is a Part Writing Calculator?
A part writing calculator is a specialized tool designed for music students, composers, and arrangers to check four-part harmony for common voice-leading errors. Part writing, also known as voice leading, is the art of combining different melodic lines to create a cohesive harmonic progression. This calculator specifically analyzes the voicing of a single four-part chord written in the traditional Soprano, Alto, Tenor, and Bass (SATB) style, which is a cornerstone of classical music theory education.
Unlike a financial calculator that crunches numbers, a part writing calculator evaluates the relationships between notes based on a set of established rules from the Common Practice Period. It helps users identify issues such as improper spacing between voices and voice crossings, ensuring the resulting harmony is clear, singable, and follows stylistic conventions. For anyone studying music theory, this tool provides instant feedback that is crucial for mastering the complexities of four-part harmony.
Part Writing Rules and Explanation
There isn’t a single mathematical formula for part writing. Instead, it’s a system of rules and guidelines that govern the vertical relationship (intervals) between notes in a chord. This part writing calculator focuses on two fundamental “vertical” rules: Voice Spacing and Voice Crossing. Other critical rules, like the prohibition of parallel fifths and octaves, apply to the *movement between two chords* and are discussed in the FAQ section.
| Rule | Meaning | Typical Range / Limit | Why it Matters |
|---|---|---|---|
| Voice Spacing | The interval between adjacent upper voices (Soprano-Alto and Alto-Tenor) should not be too wide. | Should not exceed a perfect octave (12 semitones). | Excessive spacing creates a “hollow” or thin texture and breaks the blend of the choir. |
| Voice Crossing | A lower voice should not be written higher than a higher voice. | Soprano > Alto > Tenor > Bass. | Voice crossing confuses the listener’s ear, making it difficult to follow the individual melodic lines. It breaks the independence of the voices. |
| Voice Overlapping | A voice should not leap to a note that is lower than the previous note of the voice below it. (Note: This calculator checks the static result, not the movement into it). | Soprano’s note should be higher than the Alto’s previous note. | Similar to voice crossing, it creates confusion and disrupts the clarity of the lines. Learn more about SATB voicing rules. |
Practical Examples
Understanding the rules is easier with concrete examples. Here are two scenarios using this part writing calculator.
Example 1: A Correctly Voiced C Major Chord
A standard, well-voiced C Major chord demonstrates good part writing principles.
- Inputs: Bass: C3, Tenor: G3, Alto: C4, Soprano: E4
- Analysis:
- Soprano (E4) to Alto (C4) = Major Third (4 semitones) -> OK
- Alto (C4) to Tenor (G3) = Perfect Fourth (5 semitones) -> OK
- All voices are in order (S > A > T > B) -> OK
- Result: No errors found. The chord is well-voiced.
Example 2: A Chord with Spacing and Crossing Errors
This example shows what happens when the rules are broken.
- Inputs: Bass: E2, Tenor: B3, Alto: G3, Soprano: F4
- Analysis:
- Soprano (F4) to Alto (G3) = Major Seventh (10 semitones) -> OK
- Alto (G3) to Tenor (B3) = Major Sixth (9 semitones) -> OK, but wait…
- Voice Crossing Detected: The Tenor note (B3) is higher than the Alto note (G3). This is a primary error.
- Result: An error message “Voice Crossing: Tenor (B3) is higher than Alto (G3)” would be displayed.
How to Use This Part Writing Calculator
Using this calculator is a simple, three-step process designed to give you immediate feedback on your chord voicings.
- Enter Your Notes: For each of the four voices (Soprano, Alto, Tenor, Bass), use the dropdown menus to select a note name (e.g., C, F#, Bb) and its corresponding octave. The standard vocal ranges are pre-selected for convenience.
- Analyze the Harmony: As you select notes, the calculator automatically runs its analysis in the background. The visual staff will update to show your chord, and the results box will refresh instantly with any detected errors. You can also click the “Check Harmony” button to trigger the analysis manually.
- Interpret the Results: The results section will either give you a success message or a list of specific errors. Each error message will tell you exactly which voices are involved and what the problem is, allowing you to quickly make corrections. Explore different voice leading principles to find solutions.
Key Factors That Affect Part Writing
Beyond the simple rules of a static chord, many factors influence good part writing when creating a full progression. This part writing calculator is your first step in understanding these complex interactions.
- Chord Choice: The selection of chords (e.g., I, V, vi, IV) forms the foundation of the progression and dictates the available notes for each voice.
- Chord Inversion: Using chords in root position, first inversion, or second inversion changes the bass note and dramatically affects the melodic shape of the bass line and the options for the upper voices.
- Melodic Contour of the Soprano: The soprano line is the primary melody. A good melody has a clear shape, a single high point (climax), and is mostly conjunct (stepwise).
- Motion Between Voices: To maintain independence, voices should move in contrary or oblique motion when possible. Avoiding parallel motion is a key goal. Check out our guide on common part writing errors.
- Resolution of Tendency Tones: Certain notes, like the leading tone (the 7th scale degree), have a strong pull towards a note of resolution (the tonic). Proper handling of these tones is crucial for smooth voice leading.
- Doubling: In a four-part texture with three-note chords (triads), one note must be doubled. The choice of which note to double (usually the root) impacts the balance and stability of the chord.
Frequently Asked Questions (FAQ)
- What does SATB stand for?
- SATB stands for Soprano, Alto, Tenor, and Bass, which are the four main voice types used in classical choral music. It represents the standard four-part texture this calculator analyzes.
- Why can’t the Soprano and Alto be more than an octave apart?
- This rule exists to ensure the upper three voices (S, A, T) blend into a cohesive harmonic unit. When the Soprano and Alto are too far apart, the harmony sounds hollow and the two voices no longer feel connected.
- What’s the difference between voice crossing and voice overlapping?
- Voice crossing occurs within a single chord when a lower voice is higher than an upper voice (e.g., Alto above Soprano). Voice overlapping occurs between two adjacent chords, where a voice leaps to a pitch that is lower/higher than the pitch just sung by an adjacent voice. This calculator checks for voice crossing.
- Why doesn’t this calculator check for parallel fifths and octaves?
- Parallel fifths and octaves are a crucial part writing error, but they are an error of *motion* between two different chords. Since this calculator analyzes a single, static chord, it cannot detect parallel movement. An article on how to check for parallel fifths in music can provide more context.
- Can a tenor note ever be higher than an alto note?
- No. In strict SATB part writing, the voices must always remain in order from highest to lowest: Soprano, Alto, Tenor, Bass. A tenor note higher than an alto note is a “voice crossing” error.
- What are typical vocal ranges?
- While professional singers can exceed these, typical ranges for choral writing are: Soprano (C4-A5), Alto (F3-D5), Tenor (C3-A4), and Bass (E2-C4). This calculator uses these as a guideline for its default octave selections.
- What does it mean for a result to be “unitless”?
- In the context of this calculator, the “calculation” is a check against rules, not a mathematical computation with physical units. The results (errors or success) are qualitative statements about harmonic structure, so they are unitless.
- How can I fix the errors this calculator finds?
- If you have a spacing error, move one of the voices to be closer to the other. If you have a voice crossing error, you must re-voice the chord so the notes are in the correct order (e.g., move the lower voice down or the higher voice up).