Rhythm and form.

We can imagine pitch as Y axis and time as X axis.

Note durations

In western notation note duration is always expressed as fraction of beat rather than in seconds:

(illustrations are from Wikipedia)

  • Semibreve (whole note in US) - full duration of one bar in 4/4 meter.

  • Minim (half note) - semibreve / 2

  • Crotchet (quarter note) - semibreve / 4

  • Quaver (eighth note) - semibreve / 8

  • Semiquaver (sixteenth note) - semibreve / 16

  • Demisemiquaver (thirty-second note) - semibreve / 32

The same we can do with pauses - rests:

  • 1 -

  • 1/2 -

  • 1/4 -

  • 1/8 -

  • 1/16 -

  • 1/32 -

Beams

Notes with “flags” can be joined using a beam

This can ease reading.

Tuplets

Occasionally we need to subdivide rhythm differently, we can use tuples e.g. for 3 notes in 2:

These actually changes duration of these notes. Basically this notation says play 3 notes in 2 quarter notes, so duration of this modified quarter note is 2/3 of an ordinary one.

Extensions

We can extend note duration.

Either using a tie:

There can be multiple ties in a row. Tie means - play the first note with the duration = sum of all tied notes.

Or using dotted note:

This means play the note with duration = its ordinary duration + half. One can use multiple dots, each dot adds another halved period. It is important that the dot is on the side (dots in other locations mean other stuff).

One can mark a note using Fermata - out of time pause:

The performer decides on their own how long the pause should be. Rule of thumb - twice of the note duration.

Meter

Simple

  • Duple - 2 beats per bar.
  • Triple - 3 beats per bar.
  • Quadruple - 4 beats per bar (aka common time)

Time signature is written as a fraction. Numerator is “beats per bar” and denominator is “beat type”. In other words denominator defines note type (i.e. duration) by giving its bar fraction, e.g. 4 means quarter. Numerator tells how many such notes are there per one bar.

Beats can be weak and strong. In 4/4 usually 1 and 3 are strong.

Beats are subdivided into two.

Compound

Beats are subdivided into three.

Usually denominator is 8 and numerator mod 3 = 0.

Form

Anacrusis - unstressed notes before the first bar line of a piece (can be one note aka pickup note).

Phrase - complete piece (e.g. 4 bars or one breath etc).

Rhythms are combined into beats, beats into bars, phrases, periods, sections, movements (or songs), symphonies or concertos (or albums).

Motive - is an isolated short musical phrase.

Combining sections

Binary form - A B (usually B is in different key)

Ternary - A B A or A B A’ (sonata, A’ means A modified). Exposition -> development -> recapitulation

Rondo form ABACA

There is 12 bar blues.