History of the acoustic guitar
The guitar origins are in Babylonia and dated back to 1850 B.C as clay plaques were dug up of people playing musical instruments which resembled the modern acoustic guitars showing distinct bodies and necks. Later evidence was found in Ancient Egypt that indicated instruments with marked frets along the neck of a primitive guitar.
How the sound is made:
If you put your finger gently on a loudspeaker you will feel it vibrate - if it is playing a low note loudly you can see it moving. When it moves forwards, it compresses the air next to it, which raises its pressure. Some of this air flows outwards, compressing the next layer of air. The disturbance in the air spreads out as a travelling sound wave. Ultimately this sound wave causes a very tiny vibration in your eardrum - but that's another story.
At any point in the air near the source of sound, the molecules are moving backwards and forwards, and the air pressure varies up and down by very small amounts. The number of vibrations per second is called the frequency which is measured in cycles per second or Hertz (Hz). The pitch of a note is almost entirely determined by the frequency: high frequency for high pitch and low for low .
Page Two: Jayden Foura
The strings
The pitch of a vibrating string depends on mass of the string, tension and the length of the string: strings with more mass vibrate more slowly. On steel string guitars, the strings get thicker from high to low. Tension is varied by using the tuning pegs: tighter gives higher pitch. Similarly, shorter string gives higher pitch. The sound produced by the string is faint which is then amplified by it...
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...ibrates a little almost like the air in a bottle when you blow across the open lid section of the top. In fact if you sing a note somewhere at F#2 while holding your ear close to the sound hole of the guitar, you will hear the air in the body resonating. This is called the Helmholtz resonance. Another way to hear the effect of this resonance is to play the open (A) string and, while it is vibrating, move a piece of cardboard back and forth across it. This stops the resonance (or shifts it to a lower frequency) and you will notice the loss of bass response when you listen to the sound hole. The air inside is also coupled effectively to the lowest resonance of the top plate.
The Helmholtz resonance of a guitar is due to the air at the sound hole oscillating, driven by the springiness of the air inside the body. This is analysed quantitatively in Helmholtz Resonance.
It was proposed that if the length of the PVC pipes were to increase, then the sound produced will have a lower amplitude each time because the sound will lose energy as it continues in the pipe for a certain amount of time. However, the data actually showed that with every increase in pipe length, the amplitude got louder as well, thus refuting the hypothesis. These results made sense because what was created inside the PVC pipes was a standing still sound wave, or a resonance wave. These kinds of waves have certain locations on its wavelength in order for the change in sound to be heard, which it usually half a wavelength. With this, the tuning fork is 83.3Hz and a usual wavelength is about 300Hz, 300/83.3 = 3.6 meters, which is about 4 meters (half = 2 meters). So for the change in sound to be heard, the pipes had to be about 2 meters in change according to the frequency of the tuning
The mechanical motions of the ossicles directly vibrate a small membrane that connects to the fluid filled inner ear. From this point, vibration of the connective membrane (oval window) transforms mechanical motion into a pressure wave in fluid. This pressure wave enters and hence passes vibrations into the fluid filled structure called the cochlea. The cochlea contains two membranes and between these two membranes, are specialized neurons or receptors called Hair cells. Once vibrations enter the cochlea, they cause the lower membrane (basilar membrane) to move in respect to the upper membrane (i.e. --the tectorial membrane in which the hair cells are embedded). This movement bends the hair cells to cause receptor potentials in these cells which in turn cause the release of transmitter onto the neurons of the auditory nerve. In this case, the hair cell receptors are very pressure sensitive. The greater the force of the vibrations on the membrane, the more the hair cells bend and hence the greater the receptor potential generated by these hair cells.
Sound is a wave, which can change in pitch according to changing air pressure. It is produced by the vibrations of objects. Waves can be measured by speed (v), frequency (f), wavelength (λ), and period. The frequency of a wave describes how many cycles of a wave occur per unit time. A sound with a high frequency has more wavelengths in a set amount of time than a sound with a low frequency. High frequencies have smaller wavelengths, and low frequencies have larger wavelengths. The higher frequency, the higher the perceived pitch. The wavelength, frequency, and speed are all related by the equation: v = fλ. They can also be used in the equation: f = v/λ.
Sound is created by the air particles vibrating against each other. Sound can travel through all types of mediums, such as solids, liquids and gases. When going through these mediums, the sound travels in waves known as longitudinal(figure 3) and transverse(figure 2) mechanical waves. The variations in sound are caused by the different frequencies of vibrations. The difference in the two types of sound waves is; a transverse wave travels just like when you make a rope go up and down, the waves move along in a vertical direction, whereas a longitudinal wave moves in a horizontal direction pushing the waves along.
B) In order to function, guitar pickups have to produce sound, so that’s when an electric guitar senses the vibrations of the strings electronically and routes an electronic signal to an amplifier and speaker. The sensing occurs in a magnetic pickup mounted under the strings on the guitar’s body. The pickup consists of a bar magnet wrapped with as many as 7,000 turns of fin wire. Coils and magnets can turn electrical energy into motion. In the same way, they can turn motion into electrical energy. In an electric guitar, the vibrating steel strings produce a corresponding vibration in the magnet’s magnetic field and therefore a vibrating current in the coil. Some pickups use screws for polepieces so that the height of each polepiece can be adjusted. The closer the polepiece is to the string, the stronger the signal. The upper variable resistor adjusts the tone. The resistor and capacitor form a simple low pass filter. Th...
For us to hear, we need ears with an important piece, the eardrum. We hear sound because when a sound is created, there is a change in air pressure. Because of this change in pressure, waves are produced, flying all over the place. On the guitar, when the string vibrates, the change in air pressure causes the air particles to move around. There are air particles all around us, so when the sound wave crashes into these particles, they all collide until they reach our eardrums. When the air particles crash into our eardrum, they will hit against all the other components of the ear and the sound will enter our brain.
There are several types of instruments that allow you to have a variety of sounds. There is also a wide variety of bass guitars, but the difference between bass guitars and other instruments is that no matter what type of bass you get, there sound really is not going to vary to much. The bass guitar unique sound is what gives a song structure.
Strings can alter the sound of a guitar by a large factor. Strings on acoustic guitars are much larger than on electric guitars. This is because acoustic guitars produce entirely their own sound where electric guitars can alter their sound by using amplifiers and foot pedals. Strings can also be made of different materials. Most strings for electric guitars are a type of coated metal while acoustic guitars can use nylon strings to produce a softer sound and are easier on the fingers.
First of all, it is important to know that sound waves can travel through many other substances besides air, and thus allow us to hear as they vibrate air first, then the eardrum, which in turn vibrates the malleus, incus, stapes, and then the
Most electric guitars were hollow bodied. They gave the guitarist volume, but at a price. At high volume they woul...
Sound can be divided into 2 kinds: Simple and Complex. Imagine a simple tone as a sine wave that comprises of one single frequency, which in fact is the simplest oscillation that can occur in nature. This means, that it cannot be further analyzed in simpler oscillations. The complex sound, on the other hand, consists of a fundamental frequency (which is the lowest one and usually carries most of the intensity) and of some other called overtones. When these overtones are integer multiples of the fundamental (including the fundamental), then we talk about harmonic overtones.
There has to be definite sound frequency at which all matters vibrate as one. Some architectural spaces can cause a faintest sound to magnify and cause the whole space to vibrate, affecting all inside
Sounds can be differentiated from each other through identifying its qualities, such as pitch, amplitude, speed and timbre. Pitch is able to be determined by the frequency of sound waves, and is measured in hertz (Hz). It can be seen in a soundwave by measuring the distance two corresponding points in the same soundwave, or the wavelength. Humans can detect between 20-20000 hertz; sounds with pitches below this are called subsonic, and sounds with pitches higher are called supersonic. Pitch determines the way a note sounds. Due to the way we perceive sounds, pitches around 4000 Hz sound the loudest to a normal humans ear. Amplitude is a measurement of the loudness of a sound. Amplitude can be seen in a soundwave by measuring the distance between the crest (top) and the trough (bottom) of a soundwave. Amplitude is measured in decibels, (dB), a logarithmic scale from 0-140. 0 decibels represents the faintest sound which is able to be heard by humans, and 140 represents the sounds which leads to hearing loss in a normal human being. Amplitude can be seen in a wavelength by Decibels and hertz, together, determine the total power output of a sound at a distance, in the following equation.
The ear is looked upon as a miniature receiver, amplifier and signal-processing system. The structure of the outer ear catching sound waves as they move into the external auditory canal. The sound waves then hit the eardrum and the pressure of the air causes the drum to vibrate back and forth. When the eardrum vibrates its neighbour the malleus then vibrates too. The vibrations are then transmitted from the malleus to the incus and then to the stapes. Together the three bones increase the pressure which in turn pushes the membrane of the oval window in and out. This movement sets up fluid pressure waves in the perilymph of the cochlea. The bulging of the oval window then pushes on the perilymph of the scala vestibuli. From here the pressure waves are transmitted from the scala vestibuli to the scala tympani and then eventually finds its way to the round window. This causes the round window to bulge outward into the middle ear. The scala vestibuli and scala tympani walls are now deformed with the pressure waves and the vestibular membrane is also pushed back and forth creating pressure waves in the endolymph inside the cochlear duct. These waves then causes the membrane to vibrate, which in turn cause the hairs cells of the spiral organ to move against the tectorial membrane. The bending of the stereo cilia produces receptor potentials that in the end lead to the generation of nerve impulses.