A student hears a wide ascending leap that sounds bright and consonant — like a major third, but much wider. What is the most likely interval, and what strategy identified it?
AA major sixth — it is the inversion of the major third and sounds similar
BA major tenth (compound major third) — identified by mentally reducing the span to its simple equivalent, which retained the characteristic brightness of a major third
CA major thirteenth — compound intervals always sound much larger than their simple versions
DA minor seventh — wide leaps tend to be dissonant
The correct strategy is to reduce mentally to the simple equivalent: if the quality sounds like a major third, and the span is larger than an octave, the interval is a major tenth (major third + octave). This works because the octave is acoustically transparent — shared overtones mean the octave adds nothing new to the interval's character.
Question 2 Multiple Choice
Why do compound intervals retain the consonant or dissonant character of their simple equivalents?
ABecause higher pitches always sound more consonant, making compound intervals naturally clearer
BBecause the interval names are inherited, so the ear is trained to hear them as similar
CBecause the octave is acoustically transparent — notes an octave apart share nearly all the same overtones, so the octave disappears perceptually, leaving the simple interval's quality intact
DBecause compound intervals are simple intervals played more slowly, giving the ear more processing time
Notes an octave apart share nearly identical overtone series (the octave is the first harmonic). Adding an octave to an interval introduces no new spectral information that would change the interval's character. The dissonance or consonance is determined entirely by the non-octave component, which is why a major ninth sounds like a major second and a major tenth sounds like a major third.
Question 3 True / False
A major ninth and a minor ninth share the same perceptual character because they are both compound intervals.
TTrue
FFalse
Answer: False
Major and minor ninths retain the characters of their respective simple equivalents — the major second and the minor second — not a generic 'compound interval' quality. A major ninth sounds open and stepwise like a major second; a minor ninth sounds sharp and tense like a minor second. The quality is inherited from the simple interval, not from being compound. Compound intervals do not form a homogeneous perceptual category.
Question 4 True / False
Recognizing compound intervals by ear draws on the same perceptual skills as recognizing simple intervals, extended to a wider pitch span.
TTrue
FFalse
Answer: True
Because compound intervals retain the character of their simple equivalents, existing recognition skills transfer directly. You are not learning new interval qualities — you are extending the seven familiar qualities to a larger pitch range, using octave-reduction as the bridge. Fluency with simple intervals is the prerequisite, not a separate skill.
Question 5 Short Answer
What mental strategy makes compound interval recognition by ear tractable, and why does it work acoustically?
Think about your answer, then reveal below.
Model answer: The strategy is to mentally reduce the compound interval to its simple equivalent — ignore the octave displacement and ask 'what simple interval does this sound like?' It works because the octave is acoustically transparent: notes an octave apart share nearly all the same overtones, so the octave adds no spectral content that would change the interval's consonant or dissonant character.
This means compound intervals are not a new skill set — they extend the seven simple interval qualities to a wider span, with octave-reduction as the translation mechanism.