CD Test 1
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This 14 page Study Guide was uploaded by Leah Larabee on Tuesday March 10, 2015. The Study Guide belongs to CD 411 at University of Alabama - Tuscaloosa taught by Dr. Buhr in Spring2015. Since its upload, it has received 312 views. For similar materials see Speech Science in Language at University of Alabama - Tuscaloosa.
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Date Created: 03/10/15
CD 411 Test 1 Study Guide CH 1 A source of sound must be able to vibrate To vibrate a source must have 0 Mass m I How much matter is associated with an area of space 0 Elasticity E I Tendency to return to equilibrium 0 To transmit a sound in a medium it must also have these two qualities Atmospheric pressure lb in2 I The higher you go the pressure decreases Weight is an attractive gravitational force 0 Weight is proportional to mass 0 Mass is the quantity of matter present I Air has mass and weight 0 Mass and density are proportional I Density is a quantity derived from another quantity mass 0 Density p 0 Unit of measure is kgm3 I Increase compression I Decrease rarefaction I They move through the medium associated with tuning fork Elasticity E 0 Property that enables recovery from distortion of shape or volume 0 Tuning fork I The more frequency per second the higher pitch we perceive I Amplitude of displacement is proportional to force applied I The higher the displacement the higher the force Displacement and force are proportional Inertia o Newton s First Law I All bodies remain at rest or in state of uniform motion unless a force acts on it I Magnitude of inertia is directly proportional to mass Thus mass is a measure of inertia o Newton s Third Law I With every force there must be an equal and opposite reaction force 0 Hammernail Batball I A force cannot exist alone I Vibration elasticity is the reaction force to inertia 0 Friction causes vibration to stop 0 Air particles 0 Very small and do not move very far I Bump into each other 0 Particles move about positions of equilibrium because I Inertia I Elasticity I A medium an area is not displaced over great distance 0 Sound 0 Characterized by propagation of density chang through elastic medium 0 Physical quantities associated with sound I Mass m I Density p I Force F I Pressure p I Displacement x o Fundamental quantities MKS metric system I Length 0 m meter Distance amount of spatial separation between two points I Mass 0 kg kilograms Defines the magnitude of inertia The quantity of mass defines the amount of inertia I Time s seconds Derived quantity 0 Is a product quotient of the 3 fundamental quantities I Displacement x Change in position 0 Is a vector quantity that incorporates magnitude and direction I Velocity c 0 Amount of displacement per unit time Or the timerate of displacement 0 Vector quantity 0 c xT displacement time I Speed 5 Is a scalar quantity only has magnitude 5 DT distance time I Acceleration a I The timerate change in velocity Vector quantity magnitude and direction 0 a Ac T change in velocitytime I C2C1T how to find Ac Velocity cannot change without acceleration I Force F I A push or pull or distortion of matter acceleration of matter The product of mass and acceleration o Newton s Second Law I F ma Object has mass inertia which opposes change in motion force is applied to overcome inertia 0 Newton N MKS I Unit of force I Or dyne cgs I Pressure p Measured in the Pascal Pa 0 Force per unit area 0 p Fa Force area 0 Hooke s Law I Magnitude of restoring force Fr is directly proportional to magnitude of displacement I Must be even 0 Stiffness is the spring constant k I Compliance is the inverse of stiffness The stiffer the springs the less compliant Pendulum o Restoring force is gravity 0 Sustained vibratory motion is due to I Inertia I Gravity o Momentum M I Mass x Velocity 0 M mc Energy is the capacity to do work 0 Can produce change in matter then work is done 0 Something that a body possesses I Work is something that a body does and can be measured I W Fd Force x Distance Ioule is the unit of work MKS 0 Energy is not depleted it is transferred or transformed I Potential energy Stored energy I Kinetic energy 0 Energy of motion 0 KB is transformed to thermal energy heat I Referred to as damping Amplitude o A vector quantity related to displacement Frequency f o Cycles per second 0 Hz I Inversely proportional to length I Proportional to gravity Period T o The time required to complete one cycle 0 T 1f o f 1T I Inverse of frequency CH 2 0 Type of Proportional relationship 0 00000000 m and Length are proportional m and gravity are inversely proportional Period and Frequency are inversely proportional Frequency and Length are inversely proportional m and Density are proportional p m Weight and m are proportional wm Amplitude and Force are proportional Displacement and Force are proportional xF Inertia and Mass are proportional I Tophat questions 0 Density refers to mass unit volume 0 What is derived from velocity acceleration the change in velocity over time 0 1Nm2 is pressure mass and velocity describes momentum Equations O 0000 O 0 Force Mass x Acceleration F ma Work Force x Distance W Fd Momentum Mass x Velocity M mc Pressure Force Area p Fa Speed Distance Time s dT Scalar quantity Acceleration Change in Velocity Time a AcT Vector quantity Velocity Displacement Time c xT Vector quantity Frequency 1Time f 1T Time 1 Frequency T 1f Density MassVolume p mv Simple Harmonic Motion Hooke s Law 0 Magnitude of restoring force is proportional to distance displaced O Restoring force is equal to the amount displaced Frocx O Magnitude of restoring force must change over time AKA so does the distance displaced c o c cg A Values 0 Displacement X Velocity c I D spracemem X l l l l l l l I Acceleration a O 3 g g 8 E a g 0 Force F o m decrees 0 Pressure p Momentum M Displacement The display is called a time wave form or wave form 0 the wave I Air does not actually do this its just a representation SHM simple harmonic motion 0 A uniform circular motion The concept of SHM 0 Simple harmonic motion the type of motion that the spring mass system and the air molecule undergoes It can also be called sinusoidal motion Uniform circular motion Occurs when a body moves around the circumference of a circle at a consistence number of degrees of rotation per second 0 A wheel rotates clockwise o The piston moves back and forth to move the wheel I Rectilinear motion Mass spring system 0 Motion is rectilinear not circular Displacement Waveform 90 and 270 correspond to Xmax 0 180 and 360 corresponds to equilibrium 0 One full rotation through 360 is one cycle Sine of a triangle The ratio X r is a constant for any given angle 0 Xr the Sine ofthe angle 0 b r the cosine of the angle 0 Xb the tangent ofthe angle 0 The height of each projection is now the sine 0 of the angle 0 Not X displacement Slide 14 practice o Projections are superimposed because the ratio x r is constant To find the sine of angle A 1 Given the angle ex 45 O o Sin45 707 The sine of the angle corresponds to the percentage of maximum displacement XMAx o 707 x 100 707 OfXMAX Sinusoidal Motion Five dimensions of sine waves 1 Amplitude 2 Frequency 3 Period 4 Phase 5 Wavelength Amplitude 0 Measure of the strength magnitude of the sound wave 0 In most examples amplitude will refer to the sound pressure 0 As more molecules are pushed outward there is an increased number of molecules per unit space which results in increased density compression As the balloon de ates the molecules move back toward their original position spreading out causing a region of decreased density rarefaction Instantaneous Amplitude a o The amplitude of the waveform at some specified instant in time or at some specified angle of rotation o The mean instantaneous amplitude will normally be 0 0 Maximum Amplitude A o The instantaneous amplitude that corresponds to 90 or 270 0 PeaktoPeakAmplitude 0 Absolute difference between the maximum amplitude at 90 and 270 RootMeanSquare Amplitude o rms a o o rms is the standard deviation of all instantaneous amplitudes a I rms A 707 I Mean Square 0 Rms A 2 o A2 2 FullWave Rectified Average 39 FWAVG A 636 HalfWave Average I HWAVG A 318 Amplitude 0 Particle velocity leads particle displacement by 90 0 Because displacement is at 90 and velocity is at 0 at the 14 mark Particle acceleration leads particle displacement by 180 0 Newton s 2nd law Fi ma 0 Hooke s law Fr kx o Newton s 3rd law FiFr I k is a constant and does not change Refer to sllde 32 I mass also does not change a and x must be opposites I Pressure and Velocity are in phase together Comparisons Among Metrics 0 While the instantaneous amplitudes vary sinusoidally over time the other metrics are described by straight lines horizontal to the base line and do not vary These values remain constant over time because they are timeaveraged Characteristic of a wave that you can measure 0 Frequency Hz I Hz to KHz 1000 Hz 0 Reciprocal of this is a Period T I Inverse of each other Sec to ms 001 s x 1000 Frequency 0 The rate in Hz at which a sinusoid repeats itself I The number of cycles per second 0 The frequency with which a system oscillates freely is fnat O Fnat I FnatlS proportional to k I FnatiS inversely proportional to m 0 Guitar string example I F 1 2L t m I t tension 0 only applies to the lowest frequency of fundamental freq 0 This concept is important to voice production because the frequency of the vocal folds depends mainly on the length crosssectional mass and tension of the folds I The natural frequency of vibration of a guitar string is inversely proportional to the square root of the cross sectional mass TRUE 0 Alternate ways to express frequency I Degreess 1 Hz 3600 s I 10 Hz 36000 s I 2H Radians 5 Circle divided into 2H 2 X 314 62832 o 1 Hz 211 Radians s I it is a quotpie slicequot 1 radian 573 0 I 360 ZHr I a ZHf 0 Phase 4 o The four points in a circle I A 00 I B 900 I C 1800 I D 2700 0 Starting phase the displacement in degrees at the instant the vibration or rotation begins 0 Instantaneous Phase I Angle of rotation at some specified moment in time I Can also be called the phase angle 0 When frequencies are different they mirror each other I Relations all by 90 0 unless on opposite sides then 180 0 180 C A c I B leads A by 90 C leads B by 900 C leads A by 180 0 D leads B by 1800 I B lags C by 900 Wavelength A A Distance traveled during one period 0 Unit is meters I Directly proportional to the speed of sound I Inversely proportional to frequency 0 Two quantities are measured with respect to m 0 Frequency f 0 Speed of sound 5 I 7v sf I Example in air 0 f 1100 Hz S 340 ms A o 3401100 3m CH 3 Scales 0 Nominal o Categorical o Objects can be equal or different Ordinal 0 Symbols that differentiate things but correspond to some order I AgtBgtCgtDgtE Radial o Exponential I Xn Interval 0 Size of interval between adjacent numbers is known as a constant I Aka linear scale 0 Size of interval is called the base 0 Adding or subtracting the base to each interval will give you the next one 12345 n1 I 102030 n10 Laws of Exponents 0 Law 1 x3 xb x3lb o MultiplicationAdd a b 0 Law 2 xaxb x3quotb 0 Division Subtract a b 0 Law 3 x31b xab 0 Power Multiply a and b Rules Any base raised to the zero power is 1 o X0 0 Any base raised to the first power equals the base 0 X1 X Antilog Long B gt XB A Log 2 8 3 o 23 8 Sound Energy Absolute power 0 One sound wave is compared with the absolute power in another reference wave 39 LBVBI Wx WR Wx is the power of interest 0 WR is the reference power I The measure of level is meaningless unless WR is specified 0 Absolute intensity 0 Intensity energy per second per square meter I Unit watt m2 39 IX IR 0 Bel I Level gt Log10 Ix IR I N bels Log1o Ix IR 0 Bel is a level it is a ratio the log of the ration is called a Bel o Decibel I Decibel is 110 ofa bel 39 N 3 10 L0g1o Ix IR 0 Rules 0 For every 10 step level change in Ix I dB changes by 10 dB 0 For every 2 fold level change in Ix I dB changes by m CH 4 Sound Intensity and Sound Pressure The Decibel 1 Sound Energy 0 It is transferred through a medium at some rate i Power I The rate at which energy is transferred 0 It is expressed in Watts 0 Is the rate at which energy is consumed ii Energy The capacity to do work 0 The WATT i 1 Watt 1 Ioule s MKS 1 joule a force of 1 Newton acting through a distance of 1 meter 0 Absolute power i One sound wave is compared with the absolute power in another reference wave 39 LBVBI Wx WR o Wx is the power of interest 0 WR is the reference power The measure of level is meaningless unless WR is specified 0 Absolute intensity i Intensity energy per second per square meter 0 Unit watt m2 0 Ix IR ii Bel 0 Level gt Log10 Ix IR 0 N bels Log1o Ix IR o Bel is a level it is a ratio the log of the ration is called a Bel i Number of bels will be equal to ii The base is redundant 10 0 Positive be i lx gt lR ii Numerator is greater that denominator 0 Negative bel i lx lt lR ii Denominator is greater than numerator iii Decibel Decibel is 110 of a bel o N dB 10 Log1o Ix IR 0 0 dB means i Ix IR 0 Rules 0 For every 10 step level change in Ix i dB changes by 10 dB 0 For every 2 fold level change in lx i dB changes by Absolute Intensity dB level of 0 does not mean there is not sound Reference and absolute intensity are the same Test question 0 The reference intensity must always be specified I Standard reference 0 103912 wattm2 I Two steps to follow for decibel problems 1 Select equation to use 2 Form a ration gt calculate log of ration gt multiply by 10 SHORT CUTSLIDE 34 0 Example Given dB IL Ratio dB 2 2 3 2D1V1de by 10 a 2 20 1010g1X1012 h 0 EL 0 3Antilog a 12 no 4 Exp Law 1 a 3 2 log Ix1039 4 Ix 102 X 103912 Ratio an 1 5 IX 103910 M 3 39 IL 10 log IX1039 I0l Io 2013 MRI 6 0 Example Given Ix 1 IX 10396 wattm2 2 dB 10 log 10396103912 3 dB 10 log 106 4 dB 60 A decibel is 10 times the log of any intensity or power ratio 0 A decibel is 20 times the log of a pressure ratio Absolute pressure ratio 39 dB 2010g10 PXPr o Pr is the reference pressure 0 Pr is 20 MPa I Pr 2 x 101 uPa 0 Example 1 dB SPL 2010g1o 2 x 106 2 x 101 100
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