Music is made of sound. But, to call it music, sound must be organized in a very special way. Knowing the sound is the first setp in the study of music.
1.1 The origin of sound
Sound is produced by vibrations of objects. In these two examples you can see the strings of two different instruments vibrating:
Violin
Guitar
Everything we hear are vibrations but not every vibration produces a sound. Vibration is considered sound only if it moves in a proper range or frequency (in a proper speed).
In this video you can listen to all the frequencies that the human hear is capable to perceive. Be careful with the volume of your loudspeakers, if they are too loud it can make you sick!!
Every sound can be represented as a wave. The parameters of waves are time (t) and space (s) and is represented in this way:
1.2 Kinds of sounds
Depending on the shape of the waves sounds can be quite different.
A) Sound/Noise
In the first place we can differentiate between noises and proper sounds.
Noise is made by irregular vibrations and is generally precived as nasty
Proper sound on the contrary is made by regular
vibrations and is generally felt as nice.
Generally speaking, music prefers sound but it also uses noises.
Different music styes uses different combinations of sounds and noises.
Rock & roll music needs the “noises” of the
drums because the kinds of feelings it want to express: Energy, fun rebelion...
On the other side, reigious music of the renaissance is going to use pure proper sounds. If you want to pray God noise is not the way so it completelly avoid the use of noise.
Pop music is in betwwen both styles. It uses mainly sounds but it includes noise in a very controlled way. In this case the drums are highlighting the rhythm with noises.
B) Qualities of Sound
Not all objects that porduce sound vibrate in the same way. Differeces in the shape of the vibration produce sounds whith different qualities
o Pitch
Pitch is the quality that allows us to diferenciate between high notes and low notes.
High pitched notes are also called sharp or acute.
Low pitched notes can be called deep sounds too.
Pitch dependens on the speed of the wave, also called frequency. The slower the speed the lower the sound.
It's in relation with the size of the vibrating object because bigger objects tend to vibrate slower.
Each musical note has a concrete speed of vibration. The central A of the piano, for example, vibrates at 440Hz (440 Times per second)
Melodies and harmonies are made combining different pitches.
Sound pitch can be represented in a graphic that way:
o Intensity
Intensity is the quality that tells apart loud sound from soft sounds. It is the space travelled by the vibration.
The harder you strike something the louder the sound it produces.
This quality is used in music to make rhythms. It also has a significant expressive power. The louder sound give more energy to the music.
Regarding rhytm you can compare this two way of playing violin. The first one is a classical musician. You can apreciate how not every note is strssed in the same way. There is a pattern in which some notes sound a bit louder than others.
This other musician plays traditional Scottish music in tha Cape breton Style of Nova Scotia (Canada). Iss music for dancing and the feeling of the rhytm is much more important. She gets that giving much more intensity to the stressed notes.
Regarding expressive power, listen to this song. It has two different sections. The first one is very calm and relaxed. And the second one is, on the contrary disturbing and full of energy. This is not because a single reason, but the intensity of both secitions plays an importan role on getting this effect.
Intensity can also be used to play with our expectations and surprise us.
o Duration
This is the characteristic of sound that differenciates between short sounds and a long sounds. Obviously it is linked with the amount of time that an object is vibrating.
It can be represented like that:
o Timbre
This quality allows us to distinguish sounds
with the same pitch, intensity and durations but made by different voices or
instruments. We can recognise the distinctive sound of a piano, a guitar, or
even the particular sound of the voice of a friend.
Specific timbres are produced because each note from a musical instrument is a complex wave containing more than one frequency. The human ear is capable of noticing tiny variations in the shape of the wave. We understand these differences as different timbres.
We could draw these differences as follow:
The election of a particular timbre has a huge influence over the character of music. Each music style chooses its own set of timbres. If you play classical music with a rock band or traditional Cantabrian music with Asian instruments the result would be surprisingly different.
Althoug there are plenty of exceptions to that rule. Watch this video of a Rock metal band playing with cellos.
This is a popular Ray Charles' song played with Azerbayani instruments.
https://www.youtube.com/watch?v=XKhbI2XUob4
o Envelope
“Envelope” is not usually considered as a quality of sound, but nevertheless it has an important role in music.
It is the way a sound changes in intensity over time.
Different instruments have different envelopes and this is determinant in the use that they are going to have in music.
Instruments that start with very strong intensity and disappear very soon have percussive envelopes. As it happens in piano, guitars and percussion instruments. This kind of instruments are used in music styles with an important rhythmic dimension. Rock or blues for example generally use this kind of instruments.
https://www.youtube.com/watch?v=J9b3ZZywQvg
On the contrary instruments with plane envelopes, with sounds that begin, hold on and disappear at the same intensitylevel, are widely used in melodic music styles European folk and classical European music use this kind of instruments. Flute or violin waves behave that way although the performer has some level of control over the intensity even in the middle of a sound. This feature is very important for musical expression. These instruments are better fitted for melodic music.
https://www.youtube.com/watch?v=fRMTmbU7QEk
