Unit 1 – Acoustics For Musicians
The Principles of Musical Instruments
Acoustic Guitar: An Acoustic Guitar is
built using very old wood which is strong enough to withstand the pressure from
the string tension but flexible enough to vibrate, thus amplifying and
sustaining the sound. Most guitars use a spruce or cedar top wood as these two
woods are lightweight so they can vibrate well but they're also strong enough
to withstand pressure. The back can be made of denser wood as this doesn't need
to vibrate. The sides need to be heated and pressed into the correct shape to
form the sides, and similarly to the top these should also allow vibrations
allowing sound to be amplified. The sound hole in the front face of the guitar
is again to help amplify the sound but it can also determine the tonal quality
of the guitar. A larger sound hole gives the guitar a more brighter tone and a
smaller sound will give a bassier tone, but this will vary between models with
different body sizes, depending on how the guitar is intended to sound. It's
important that a guitar is constructed using good quality materials, and it's
important that it's constructed precisely, as having angles measurements wrong
can cause the guitar to frequently go out of tune, and have string tension and
action problems. Often the finest guitars are hand made or bespoke guitars, as
there's greater attention paid to these details which make a guitar sound very
good, and often when paying lots of money for a custom guitar no expense is
spared on the quality of materials used. There are many ways to produce
sound on an acoustic guitar, and they vary depending on the style or genre
of music being played, but its almost always a plucking of the strings
that produces the sound. Often in modern folk or indie music a pick is used to
play open chords in a fast strumming motion, but more subtle methods like
finger picking can add a depth to the method of sound production. In Spanish
flamenco style guitar the players will grow longer fingernails on their picking
hand so when they finger pick on the nylon strings they can create a sound with
more power and attack than they would with the flesh of their thumb and
fingers. A steel string acoustic guitar has different sound qualities to a
nylon string classical guitar, the key differences are the sustain and decay of
a sound. The nylon strings produce a round and mellow sound with little sustain
and in contrast steel strings produce a bright sound with lots of sustain. The
different sound is appropriate for different styles of music, but the steel
string is the most commonly used as its natural power and sustain is greater at
supporting a vocalist.
Clarinet: There are many versions of clarinet in the clarinet family
which play at different pitches and serve different purposes, so for this
assignment I'm writing about the most commonly used clarinet of the group
called the Bb or soprano clarinet. It's the most commonly used as it has a
range of nearly four octaves, meaning it is quite diverse for use in different
pieces of music and musical performance. Clarinets have a reed just below the
mouth piece which is vibrated by passing air from the performer blowing into
the mouth piece, and this vibration creates a series of sound waves which
travel down the length of the tube and are given a rounded tone by
the bell at the end which is flared outward to allow sound waves to
escape. When a key is pressed down or a tone hole covered, the length of the
cylindrical tubing is altered, having an affect on the wavelength of the wave
created by the performer . This pressing down of certain keys changes the frequency
and therefore the pitch of the energy inside the cylinder and creates a
resonance where the cylinder resonates best. To play a high note, the length of
cylinder needs to be shortened, so the sound waves have less space to move
freely and the a harmonic properties of the wave are changed. Traditionally the
body of the clarinet has been made from African hardwood or Honduran rosewood,
but more recently bodies have been made from materials like plastic which are
cheaper to mass produce, however most players feel the plastic bodies give the
sound an artificial resonance and tone so the wooden bodies are regarded as the
best quality. The mouthpiece is usually made of rubber, and other component
like the keys and exterior metal work are chrome plated metal, which shouldn't
erode from sweat from the hands. The reed inside the mouthpiece which is
responsible for producing the sound is made either of a type of grass cane
called arundo donax or of a synthetic material which replicates the features of
the cane. It is positioned so that when the mouthpiece is blown into it's
vibration fills the space surrounding it. Both the quality and material of
these components has an impact on the tone and timbre of this instrument. The
most important factor to the timbre of this instrument is the bore, which
starts below the mouthpiece and runs through to the bell. It's almost like a
lining for the body of the clarinet, and is completely smooth inside so it
doesn't hinder the passage of waves, but gives the instrument the distinctive
sound.
Timpani Drum: A timpani drum or kettle drum is a very large drum used in
orchestral music, often to emphasize a change in the movement of the music from
a still and subtle sound to an explosion of sound or when many areas of the
orchestra are playing at one time. It's played with specialized sticks called
timpani mallets, which usually have round heads of cork or leather, each
producing a different sound from the drum. The drum skin is stretched across a
copper bowl which can be shaped differently to produce a different sound and
tone. For example a very spherical bowl will sound brighter than a parabolic
shaped bowl which is narrower at the bottom than the spherical one, and will
produce a darker bassier sound. Often both will be used by one player to vary
the sound, so it isn't repetative. The skin is stretched very tightly across
the bowl and secured with a hoop and counterhoop which hold it down before the
trus rods secure it. To ensure the sound produced doesn't vary depending on the
velocity of the striking of the drum skin, the drum needs to be
tuned. To do this the player has to equalise the tension of the tuning screws
at points around the perimeter of the drum. This means that if the drummer taps
the skin very lightly it should produce the same note as it does when they
strike it with the mallet. As an instrument this isn't supposed to over power
the lead players in the brass, woodwind or string section, so having it in tune
shouldn't make it stand out, just compliment what the other players are doing.
There are some playing techniques which change the drums sound so an it doesn't
do the latter, like dampening. This technique is used to shorten the usual
sustain of an unmuffled drum strike, and the timpanist does it by applying
pressure to the skin with his fingers and thumb. It's down to the ear of the
timpanist to work out how long to allow the sustain, as to fit with
composition.
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