Interval Analysis
The interval analysis lists the intervals that occur in a particular piece of music.
But primes of pitch ratio 1/1 are not listed, nor are octaves thereof.
Intervals wider than a fifth are reduced by an appropriate number of octaves to make them fall within a fifth.
The analysis lists both harmonic and melodic intervals.
That still implies a limitation though.
Say a melody has a quick succession of the notes A B A,
where the melodic interval A-B has a pitch ratio of 9/8 up, and the interval B-A has 10/9 down.
The analysis would then miss the interval between the two A's: a syntonic comma up which might be clearly audible.
If you download a file, you can open it in a spreadsheet program where you can set filters on any column.
Explanation of Column Headers
- measure
- The sequence number of the measure in the score.
- beats
- The number of completed beat durations within this measure after which the interval happens.
If the number is zero, the interval happens at the very start of the measure.
If it is 0.5, the interval happens after half a beat duration.
A beat duration is often a quarter note / crotchet (for music in 3/4 or 4/4 time for instance),
but music in 9/8 time has a beat duration of an eight note / quaver. Etc.
- min : sec : ms
- Minutes, seconds and miliseconds where the interval happens in the sound file.
- harmonic/melodic
- 'H' (harmonic) indicates that the two tones mentioned (next column) sound together at the indicated moment (previous column).
'M' (melodic) indiates that the first of the two tones mentioned (next column) ends at the indicated moment (previous column) and
the second tone mentioned, starts at the indicated moment.
- interval tones
- The two tones that make up the interval. For a melodic interval, the tones are in the order in which they sound.
For harmonic intervals the order is undefined.
For a melodic interval, the tones are not necessarily in the same part or voice.
For each tone in the interval, its name is given (e.g. C or F♯) and the co-ordinates in the matrix as (thirds,fifths),
where one C in the matrix has been assigned co-ordinates (0,0).
The actual octave of a tone is not reflected in its name.
- interval name
- The interval name is determined by the number of semitones and the number of letters spanned.
For instance, the interval B♭-C♯ spans two letters (B-C), and three semitones, making it an augmented second.
The interval name does not reflect the exact tuning. See the next column for that.
- ratio
- The pitch ratio in classic five limit just intonation.
Octaves are ignored.
Intervals whose pitch ratio is very near a septimal pitch ratio, have those indicated also, for instance:
| interval name | ratio |
| Tritone | 45/32 ~ 7/5 |
- cents
- A well established measure to specify a pitch ratio.
The number of cents is calculated from a pitch ratio r as follows: 1200 x log2(r).
Home