Tyler Woodruff Corbett 4th Sound and Soundproofing Sound is a very crucial part of living on earth. It is seen everyday and the science behindit mostly goes unnoticed. The science of sound is extremely interesting yet it is oddly basic.Sound can also be described as peaceful and destructive however it is believed that it is to be leftto the one listening to the sound to answer that question. Sound is a very interesting part of physics and the real world today andthroughout history. Sound can be defined in many different ways depending on how it isperceived. “The sensation produced by stimulation of the organs of hearing by vibrationstransmitted through the air or other medium.” Dictionary.com is one way sound is defined.However, if looked at from a physics point of view, sound can be defined as, “mechanicalvibrations transmitted through an elastic medium, traveling in air at a speed of approximately1087 feet (331meters) per second at sea level.” Dictionary.com. Sound can only be present ifthere are mediums for it to travel through. Some of the different types of sources that it canuse to vibrate through are forms of matter, gasses, liquids, and solids. If there is no mediumfor sound to travel through then sound can not exist in that situation that is also know as avacuum. Space is the best example of a vacuum. Sound travels in the form of oscillating waves.Longitudinal waves are waves that travel through solids, liquids, and gasses, and are sometimes
called compression waves. These forms of waves are special because they are transmitted asalternating pressure deviations that differ from the equilibrium pressure. The way that soundis acutely emitted is when the matter that is used as a medium for the deviation in the pressureoscillates back and forth it causes the energy in the waves to switch from potential to kineticrapidly thus causing sound. There are many measurement of sound that all show a different property about eachindividual sound. Frequency is the first type of measurement of sound. According toAudimute, “Frequency is the number of occurrences of a repeating event per unit time.”Audimute.com. The standard unit for measurement for frequency is hertz, which is named afterthe German scientist Heinrich Hertz. Frequency is measured by putting the number of times asound oscillates over the period of time measured. Amplitude is the next way that sound ismeasured. This is basically what is called volume in laymen terms. “Amplitude isthe magnitude of change in the oscillating variable with each oscillation within an oscillatingsystem.” Audimute.com. Amplitude is used to measure the total output through pressure andnoise from an oscillating source. RMS is the unit of measurement for amplitude. Frequency andamplitude are the two most commonly used terms to describe sound and its specifications. Thereare also a few other units of measurement that can be used to determine different sound’sindividual qualities. Watts are one of these units of measurement. In the study of sound and howsound works, “Watts can be used to describe how much total output that the system that ismaking the sound can put out.” Kamisiński, T, J Rubacha, and A Pilch. This is used in manyeveryday things like car stereos and home entertainment systems. The amounts of watts show thetotal potential output that the entire sound system can produce. All of these measurement help
show how sound works and how sound is measured, and the measurements can help study theproperties of sound. The anatomical definition of sound is one that most humans describe first before theyunderstand the physical meaning of sound. These two interpretations have sparked many debateson what the true meaning of sound should be. This also sparked the old trick question “If a treefalls in the forest and no one is around to hear it, then does it make a sound.” Unknown. Theanatomical definition of sound basically states that sound is a stimulus caused by a change inair pressure that causes oscillations to be perceived as a natural sense of the body. When soundenters in through the ear to be perceived as a sense it vibrates little hair follicles in your earwhich in turn cause you to perceive the stimulus as a sound. However, these little hairs nevergrow back once they are destroyed, and they are very easy to destroy. This is all why soundproofing is a huge part of the world today. Sound can be a very beautiful and productive thing in our world today, and it hasbeen for a very long time now. However, it can also be a huge disturbance to those around thatdo not care for the certain sound being emitted. This is where soundproofing and soundabsorption come into play. “Sound proofing is the act of completely sealing of a room orenclosure so that no sound can escape.” Doutres, Olivier, and Noureddine Atalla. Soundproofingcan be a very difficult and very expensive thing to do depending on what is being soundproofedand how big the area that is enclosing the object that is making the sound takes up. Sound is avery tricky element of physics to deal with mainly because sound uses mediums to travelthrough; therefore sound can not just be boxed in and never heard again. According to Thomas
Kletschkowski, “Soundproofing [normally] requires special materials and special equipmentbecause the noise level that the sound will come out at when in an enclosed room all depends onthe materials used, the structure of the room, and flexibility of the walls.” ThomasKletschkowski. In the structure of a normal room there is almost no means used forsoundproofing, mostly because there is no reason for complete sound blocking in a normal room.Most rooms consist of a layer of 5/8 inch thick drywall screwed to a row of two by four inchpieces of wood, with a layer of insulation, and then another piece of 5/8 inch thick drywall on theother side. This set up has a STC rating of 38-41 dB. “The STC rating or Sound TransmissionCoefficient, measures the amount of sound that escapes a room as perceived indecibels.”soundproofwindows.com. At this STC rating loud talking in the other room can beheard yet it is not clearly audible. This may work for many households that do not have thatmuch loud talking going on and do not need to have their walls soundproofed. However, forpeople that do need their walls soundproofed there are many options to choose. Most of theseoptions for sound blocking use the same concept to block sound from escaping or entering.Sound travels in wavelengths and the frequency of the wave lengths vary depending on the pitchof the noise that is being emitted. Sounds with higher pitches have higher frequencies, thus haveshorter wavelengths. On the other hand noises with lower pitches have lower frequencies andhave smaller wavelengths. Since earth has an atmosphere with air in it sound is free to travelalmost anywhere, and when a sound wave runs into a wall or another solid object it has theability to go through that object depending on its wavelength and the size of the object. The waythis works is that the sound wave enters the object and if the length of the wave is longer than theobject it enters then it will pass through to the other side of that object, and if it is shorter thenthe object then it will not pass through that object. This is why bass and other lower pitches are
what is most often heard through walls when the sound is being emitted from the other side ofthe wall. Soundproofing materials help with this affect in the way that they make the wallsthicker and denser so that less sound can pass through the wall. Other types of sound blockingmaterials are made of very dense rubber and they actual repeal the sound back at its source.Along with sound blocking materials there are also sound absorbing materials. Sound absorptionis a totally different task compared to sound blocking. While sound blocking deals withcompletely eliminating all sound that is produced by an object, sound absorption is used to justdim the sound a little bit and to make the quality of the sound actually heighten. Soundabsorption works by using many different items to “catch” the sound and take most of the reverband echo out of it; thus giving it a cleaner and more controlled sound. Some of the materials thatare used to achieve this affect include sound absorption panels and sheets, and also soundfoam. “[The] sound absorption panels are wood framed structures that have a cloth covering andis spaced out with a small amount of insulation on the inside of it.” Audimute.com. These panelswork by letting sound pass through the cloth while still reverberating off of it. Then after thesound passes through the cloth it then gets dampened by the cloth which in turn cuts back on thenoise without completely blocking it out. These work great for recording studios that need goodsound back for acoustics and recordings. The foam and the sound absorption sheets work withalmost the same principal as the sound absorption panels. They work by letting the sound getcaught inside their many ridges and letting the waves bounce around in many random wayswhile also letting it be dampened inside the air filled structures. These sound sheets and soundfoam blocks also block more sound then the panels will because they have more area for thesound to be absorbed in. These work the best for things like drum room which need soundabsorption materials but still need to sound good. In conclusion, sound has many aspects to it
and it is a very hefty task to block it and keep it under control. In conclusion sound is a magnificent part of the world as it is known in this day and ageand it will not be leaving anytime soon. The concept of sound and how it works is one of themost interesting and complex ideas in the scientific world today. However, sound still has itsdownfall and its always needing to be blocked in some place at some time. Although is has itsdownturns sound is still one of the most fascinating beautiful objects of physics on earth to date.