Music basics


Martin McBride, 2020-05-15
Tags music
Categories sound theory

We won't attempt to give a general definition of music here, it is far too broad a topic. Instead we will look at some aspects that are common to many (but not all) types of music, and how electronically created music impacts on them.

Rhythm

Rhythm is probably the most primal aspect of music. Even a simple beat on a loud drum can be powerful. Rhythm is essentially the heartbeat of music, and the tempo (the number of beats per minute) is key to the mood of any piece.

Electronic music can, of course keep time very precisely. It can also play immensely complex rhythms, switch tempo or rhythm structure at any point, overlap complex interacting rhythms of different tempo, and of course play beats faster than a human could.

Computer sound can also randomise rhythms or times.

Tonality

Most music is based on musical notes, that exist as fixed frequencies on a musical scale.

A combination of a rhythm with a sequence of notes creates melody, which is the basis of a lot of musical pieces. A melody can generally be played on almost any instrument, and will still be recognised as the same melody. It can be transposed into a different scale, which means it will be played using different set of notes (but with the same relationship to each other), and it will still be recognised as the same melody.

The concept of a melody can be extended to include various parts (sometimes called voices), separate melodies that are designed to be played together. On a piano, for example, the left and right hand might be playing different parts. In a traditional rock band you would have several parts - the drums, bass and rhythm guitar playing the backing, while the vocals, lead guitar or keyboards might alternate in playing the main melody.

A melody that has been enhanced like that is often called an arrangement. Making an arrangement of a song is a creative process in itself, and it is possible to many, make very different arrangements of the same song. The overall effect of an arrangement, including the tempo, the number voices, the range of notes played at the same time, is sometimes called the texture of the piece.

Electronic music offers a lot in this area. You have access to many different voices without needing to be skilled in lots of different instruments. Computers can even help with arrangement, as common techniques such as playing chords and arpeggios can be automated. All this means that, if you wish, you can quite easily create very rich and complex textures.

Timbre

The same note played on different instruments will sound very different, although it is still recognisable as the same note. The difference is called the timbre. It relates to the frequency spectrum of the sound.

Some instruments are capable of providing several different timbres - for example a guitar can be picked or strummed, a trumpet can be muted in various ways to alter its sound.

This is where electronic music really shines, because it provides many ways to control the spectral distribution of the sound created. There are various techniques including additive synthesis, subtraction synthesis, frequency modulation, sampling of real sounds, and granular synthesis that can be used and combined in many ways.

Time variation

A final important aspect is how individual notes develop over time. Again, electronic music gives us many ways to control how a note changes over time, including:

  • Its envelope - how the volume changes over the duration of the note.
  • Frequency spectrum changes - this includes many effects such as subtle changes in timbre over time, or slow atmospheric synth pads, through to full on wah-wah effects.
  • Periodic variation of the amplitude or frequency of the note (tremolo and vibrato).
  • Echo, reverb and chorusing effect.

Of course, not all music has all of these characteristics. There might even be forms of music that have none of them. The is the beauty of electronic music, you can create pretty much any sound it is possible to imagine.

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