Unit 3 The musical instruments

 1  Introduction

The musical instruments are machines that use sound to make music. They need two things to work:

• Producing vibrations: Sounds are produce by vibrations therefore, all musical instruments need some vibrating element. 
• Improving the vibrations: In most ocassions the original vibrations doesn't sound very nice. So we have to improve them to get the volume and timbre that we are looking for. We can get that with some kind of resonator.

•  Managing the qualities of these sounds to get different notes, durations and, sometimes, timbres and intensities.

There are no many materials able to produce proper vibrations for music. Basically we can use strings, tubes and electronic systems. Sometimes you can get proper vibrations beating other kind of object.

So, although there are a huge number of different instruments in the world, all of them can be simplify in very few groups that use the same sound principles.

Let´s see these categories in more detail.

2-    Strings

 2.1 Materials and characteristics:

The strings produce perfect pitched sounds when vibrating. The pitch is linked with the length and the thickness of the string and with the tension that it bears.

Strings can be made of different kinds of materials. Traditionally they were made of metal or gut, but currently a wide range of plastics are used for this purpose.  Nylon is one of the most used today.

 

                2.2- Resonator.

The sound produced by a vibrating string is very weak. So it must be amplified to be used in a musical instrument. We have two options to do that.

·         Sounding board: The vibration of the string in taken to a broader surface in order to amplify the sound.The shape of the sounding board influences the quality of the sound and the timbre of the instrument. 

     In this video, you can appreciate the difference between the sound of an acoustic guitar and a banjo. Both of them produce the sound by the vibrations of metalic strings that are pretty similar. The difference in the sound is given by the differences in shape and material of the sounding board.

        

·          Electric amplification: Since the 20^th century electric amplification has been applied to many string instruments. The weak sound of the vibration of the string is taken by a kind of microphones called pickups. The pickups transform the sound in an electric vibration that can be driven by wire to an electric amplifier and from there to loudspeakers.

This system has a big advantage. It allows us to change the characteristics of the wave once in the wire. You can see some of the most common guitar effects used in rock music in the video bellow.

This kind of amplification has been used in guitars and electric basses but also can be used in other instruments as violins or cellos.

 

                 2.3 – Producing the sound

We can use only 3 systems to get vibrations in a string.

·         Plucking: Moving the string using the fingers or a plectrum (pua). The instruments that use this method are called plucked string instruments. The more typical example is the guitar.

 

·         Bowing: In these instruments the vibration is produced by rubbing the strings. Usually the strings are rubbed with a bow made of tail horse hair. The most typical instrument of this kind is the violin.

·         Striking: The vibration is produced by striking the string. This system is not very used because it demands a lot of tension in the string and therefore the structure of the instrument must be strong and heavy.  Nevertheless one of the most important instruments today, the piano, works that way. In piano the stroke is made by little hammers operated by a keyboard mechanism.

    

 

 2.4- How to get different notes.

There are two different systems to get different pitches in the vibration of the strings.

·         Using different sizes of strings (length and thickness). Like in harps or in the piano.

·         Shortening the vibrant length of the string by stopping the vibration with a finger or any kind of device. Like in violins or guitars.

In In this video you can see some of the things related to the string instruments that you have read above: Production of the sound, amplification etc.

 

3-    Tubes

3.1 Materials and characteristics

The sound is produced in this case by generating vibrations in the air inside the tube. The material these tubes are made, have little influence in the quality of the sound in comparison with the tube length and shape.

The sound pitch is linked with the length and the thickness of the tube as in the strings case.

                3.2 Making the sound

In order to get sound in this kind of instruments you have to make vibrations in the air inside the tube. You have three options to do it.

·         With a reed: A reed is a strip of some material (generally cane, but also plastic or metal) that vibrates when air pass through it. Once vibrating the air is canalized through the body of the instrument.

There are two kinds of reeds. The kind of reed used influence a lot over the sound of the instrument:

-Single reed: Is made of one stripe of cane. It is used for clarinets and saxophones.

- Double reed: It is made of two stripes joined together. This is the oboe system.

 

·         Blowing over the edge: It is the system used in flutes. It consists in blowing over a sharp edge of the instrument. Part of the air gets out of the instrument and part of it gets into the instrument vibrating. There are not moving elements in that system, only the clash of the air on the edge.

You can do that by two ways:

-      With a simple hollow: and blowing the air carefully against the edge, like in traverseflutes.

-       With a mouthpiece: The mouthpiece canalise the blown air to the edge. It is easier to get the sound that way. This system is used in recorders and whistles.

 

 

·         Vibrating the lips: In this case the lips of the performer are the vibrating element. They do the function of the reeds. This is the system used in brass instruments as the trumpet. This is a trumpet mouth piece:

 

 

3.3 How to get different notes:

There are different ways of doing this:

•     Making holes in the tube.
•     Using tubes of different lengths

•      Siliding one tube into another
•      Getting different harmonic sounds by blowing harder.

In In this video  I will show you how the sound is produced in different kind of wind instruments

 

 4-    Electronic systems

Electronics systems of making sounds have become popular since the second half of the 20^th century. They are the newest branch of instruments.

Instruments that generate the sound by electronic means are different from those that generate the sound by the vibration of a string and uses electronics only for amplifying the sound.  Nevertheless there is an unresolved debate in that particular among musicologists about how to classify this second group of instruments.

We can produce an electronic sound by two means:

·         Synthetizing: Is the way used by Synthesizers. Sounds are generated by a device called oscillator that makes electronic waves. These waves can be transformed to get different timbres and generate entirely new sound or imitate that of other instruments.

·         Sampling: It consists in taking a sample of pre-existing sound and changing its frequency but keeping its timbre to get different notes from it.  By that mean you can reproduce with digital quality the timbre of any given instrument and use it for making music. The instruments that work that way are called samplers.

The emission of the sound is managed by a controller device. Most of these instruments are controlled by keyboards because keyboards offer plenty of musical possibilities for players. Nevertheless, if you are trained in the use of other kind of instrument, other controller devices are available (electronic guitars, flutes etc.).

 5Other possibilities

Any kind of material is able to produce sound when beaten. These are the percussion instruments.

There are many ways to classify percussion instruments.  For practical reasons we are going to classify them in two different categories:

·         Definite pitch of music: They are pitched in given notes (as in xylophones). These instruments are able to produce melodies.

 

·         Indefinite pitch:  These instruments only are able to emit noises. You can’t do melodies with them and has a rhythmical function.

 

6-    Summary scheme

VIBRATING ELEMENT	GETTING THE THE SOUND	RESONATOR	GETTING DIFFERENT NOTES
STRINGS	- Plucking - Bowing - Striging	-Electric amplification  -Acoustic    (SoundBoard)	- Whit a neck (guitar) - One string for each note (harp)
AIR INSIDE A TUBE	- Blowing in the edge - reeds (Single or double) - Vibrating the lips	The tube acts as a resonatos	- Opening holes in a tube - One tube for each note
ELECTRONIC SYSTEMS	- Sampling - Sinthetysing	-Electric amplification	- Changin the frecuency by electronic means
OTHER OBJECTS	- Striking	Several possibilities	- Only if definite pitch

  

7- Instruments classification.

There are many different classifications that have been developed along history. Most of them were done by practical reasons. There are systematic classifications that have two criteria in mind: the material that produces sound and the way of get it.

One of the most popular classifications today has been done from the point of view of the orchestra. This classification groups instruments, in relation with their kind of sound. And it happens that the way you produce vibrations is the most important factor that contributes to the particular characteristics of the sound of an instrument.

A)      String instruments:

·         Plucked string: guitar

·         Bowed string: violin

·         Stroke string: piano

B)      Wind instruments:

·         Woodwind:

Without reeds: flutes

With reeds: Single: Clarinet

                       Double: oboe

·         Brass wind: trumpet

C)      Electronic instruments:

·         Samplers

·         Synthesisers

D)     Percussion instruments:

·         Definite pitch of music: Xylophone

·         Indefinite pitch: drum