Download 16 באוקטובר, 2005

Music Transcription with Scale Recognition
Final Project Proposal, Spring 2017
Supervisor: Dr. Orly Yahalom, [email protected]
Goals of the project:
1. Implementing a tool for detecting the musical scale of a musical piece.
2. Incorporating this tool in an existing software for musical transcription, built in a previous project.
3. Adding an option of changing the scale of a musical sheet produced by the system.
Background:
Western music includes sounds which defer from each other by at least semitone. This gives rise to 12 basic
different sounds, as seen here:
The first note is a “low do”, and the last one is a “high do”, which sounds “similar” to the human ear. The interval
between these two dos is called an “octave”. For the most part of this project, we will not distinguish between
versions of the same note in different octaves. Although 12 basic notes are available, most musical pieces are
based on 7 notes (in either octave), following a certain musical scale. The two main kinds of scales are major
and minor. Musical tunes written in a major scale tend to sound “happy” whereas minor scale melodies tend to
sound “sad” or “serious”.
It is conventioned to describe a musical scale as a list or notest in ascending order, where the last note is one
octave above the first. Noting a tone interval by T, and a semitone by S, a major scale is any scale of the form:
T-T-S-T-T-T-S. For example, the Do major scale, also known as C-major, is:
This scale comprised of the “white keys” of the piano, and thus it does not require the symbols # (sharp), which
indicates a semitone up, or ♭ (flat), which indicates a semitone down. However, this is not the case with other
major scales. For example, mi major, or E-major is:
To avoid writing sharps for each instance, the sharps are written at the beginning of a piece written in this scale:
A minor scale is of the form T-S-T-T-S-T-T. For example, La minor, or A-minor scale:
Notice that A-minor includes the exact same notes as C-major. In fact, each of the 12 major scale has a “twin”
minor scale with this property. Moreover, many musical pieces use notes outside their main scale. Thus,
determining the scale is a non-trivial task.
Methods:
1. We will compute the frequency of appearance for each of the 12 available notes, and find a pair of twin
major and minor scales using the nearest neighbor method.
2. To decide whether the scale is major or minor, we will focus on the last note of the piece. For example, Cmajor melodies usually end with C or G, whereas A-minor melodies usually end with A or E. We will study
this issue more deeply in order to devise our procedure.