archive-edu.com » EDU » I » IUS.EDU

Total: 154

Choose link from "Titles, links and description words view":

Or switch to "Titles and links view".
  • 8b: Loudness | SOUND
    level sound pressure and sound intensity Both sound intensity W m 2 and sound intensity level SIL are numbers that can be measured precisely in the laboratory objective measurements The human ear however is an imperfect measuring instrument We hear better at a mid range of frequencies than we do at very low or very high frequencies The phon scale is a subjective measurement of loudness This scale is arrived at by asking real humans to compare the loudness of different notes and an average is taken for many people subjective The units of the phon are the same as SIL units the Decibels dB The diagram below modified from an MIT OpenCourseWare graph relates sound intensity level SIL measured in dB with laboratory instruments pressure measured in W m 2 with laboratory instruments and phons human perception A SIL of 110 dB is considered painful while a SIL of 0 is at the threshold of hearing If our ears were the same as laboratory instruments the lines would go straight across The phon scale and the SIL scale do give approximately the same number in dB but only for frequencies around 1000 Hz In other words our subjective perception of loudness and the laboratory measurement agree but only for sounds with a frequency of 1000 Hz Notice there is a dip in all the curves between 1000 Hz and 5000 Hz indicating we are more sensitive to these frequencies and this is true for all loudness readings For example suppose we perceive a sound at 4000 Hz to be 45 dB phons labeled by a blue X in the diagram The chart shows that at this loudness and frequency the dB reading in the laboratory is actually around 36 dB dotted line to the SIL axis So we perceive a sound of 36 dB measured in the lab as being much louder 45 dB if it occurs at 4000 Hz This is not surprising once you realize these are important frequencies for human speech our hearing mechanism is built to hear human voices better than sound with much higher or much lower frequencies This greater sensitivity around 3500 Hz is due to the tube resonance of the auditory canal see chapter 12 for tube resonance and chapter 10 for a picture of the auditory canal It is also the case that intensity has an effect on perceived frequency the same laboratory frequency will appear to be a slightly different frequency if the intensity is different High frequencies are perceived to be a slightly higher pitch than normal if they are very loud Low frequencies are perceived to be slightly lower than expected if they are very loud Medium loudness doesn t change the perceived pitch very much The above curves are parallel to the frequency response curves of microphones and speakers No microphone has the same sensitivity to all frequencies and no speaker reproduces all frequencies equally well as we will see in Chapter 18 on electronics Likewise our

    Original URL path: https://soundphysics.ius.edu/?page_id=912 (2016-02-01)
    Open archived version from archive


  • 8c: Just Noticeable Difference | SOUND
    when the sound is at 80 dB but need a change of 1 5 dB to detect a difference if the sound is at 40 dB to start with There is also a slight difference in the perception of loudness differences at different frequencies which is not surprising given the difference in perception at different frequencies the phon scale above Video audio examples An online test for JND in frequency Take the test Record your answers we will compare everyone s response in class What did you find out about your own Just Noticeable Difference in frequency 1 Introduction 2 Basics 2a Motion and Force 2b Newton s Three Laws Forces Simulation 2c Density and Pressure 2d Energy and Power 2e Two Energy Laws Simulation 2D Energy Conservation in a Spring 2 Summary 3 Vibration 3a Simple Harmonic Motion Simulation 3A Simple Harmonic Motion 3b Period Frequency Amplitude Restoring Force Phase 3 Summary 4 Resonance 4a Resonance Examples Simulation 4A Resonance Resonance and Tidal Bores in the Bay of Fundy 4b A Few Other Examples of Resonance Simulation 4B Resonance in a Chain 4 Summary 5 Wave Types 5a Transverse Waves Simulation 5A Transverse Waves 5b Longitudinal Waves Simulation 5B Longitudinal Waves 5c Torsional Waves 5d Examples of Waves Simulation 5C Water Waves The Electromagnetic Spectrum 5 Summary 6 Wave Speed 6a Speeds of Different Types of Waves Simulation 6A Wave Speed 6 Summary 7 Wave Behavior 7a Reflection Simulation 7A Reflection 7b Refraction Simulation 7B Refraction Simulation 7C Lenses Simulation 7D Dispersion 1 Simulation 7E Dispersion of a Square Wave 7c Adding Waves Simulation 7F Adding Wave Pulses Simulation 7G Adding Sine Waves 7d Interference Simulaton 7H Path Difference Simulation 7I Interference 7e Diffraction Simulation 7J Diffraction 7f Doppler Shift Simulation 7K Doppler Shift 7 Summary 8 Pitch 8a

    Original URL path: https://soundphysics.ius.edu/?page_id=914 (2016-02-01)
    Open archived version from archive

  • 8d: Timbre (The First Time) | SOUND
    by frequency and waveform of the sound Likewise our perception of pitch is mainly determined by the fundamental frequency but also influenced by intensity and waveform Finally timbre is determined by waveform which is determined by the other frequencies present and their phases with influences from intensity and the fundamental frequency As we will see later in a demo in class the duration of a sound also affects how we perceive its pitch loudness and timbre 1 Introduction 2 Basics 2a Motion and Force 2b Newton s Three Laws Forces Simulation 2c Density and Pressure 2d Energy and Power 2e Two Energy Laws Simulation 2D Energy Conservation in a Spring 2 Summary 3 Vibration 3a Simple Harmonic Motion Simulation 3A Simple Harmonic Motion 3b Period Frequency Amplitude Restoring Force Phase 3 Summary 4 Resonance 4a Resonance Examples Simulation 4A Resonance Resonance and Tidal Bores in the Bay of Fundy 4b A Few Other Examples of Resonance Simulation 4B Resonance in a Chain 4 Summary 5 Wave Types 5a Transverse Waves Simulation 5A Transverse Waves 5b Longitudinal Waves Simulation 5B Longitudinal Waves 5c Torsional Waves 5d Examples of Waves Simulation 5C Water Waves The Electromagnetic Spectrum 5 Summary 6 Wave Speed 6a Speeds of Different Types of Waves Simulation 6A Wave Speed 6 Summary 7 Wave Behavior 7a Reflection Simulation 7A Reflection 7b Refraction Simulation 7B Refraction Simulation 7C Lenses Simulation 7D Dispersion 1 Simulation 7E Dispersion of a Square Wave 7c Adding Waves Simulation 7F Adding Wave Pulses Simulation 7G Adding Sine Waves 7d Interference Simulaton 7H Path Difference Simulation 7I Interference 7e Diffraction Simulation 7J Diffraction 7f Doppler Shift Simulation 7K Doppler Shift 7 Summary 8 Pitch 8a Pitch 8b Loudness 8c Just Noticeable Difference 8d Timbre The First Time 8 Summary 9 Fourier 9a Wave Shape 9b Fourier

    Original URL path: https://soundphysics.ius.edu/?page_id=917 (2016-02-01)
    Open archived version from archive

  • 8. Summary | SOUND
    of sound different from measurements made in the lab End of chapter exercises Pitch Loudness and Timbre 1 Introduction 2 Basics 2a Motion and Force 2b Newton s Three Laws Forces Simulation 2c Density and Pressure 2d Energy and Power 2e Two Energy Laws Simulation 2D Energy Conservation in a Spring 2 Summary 3 Vibration 3a Simple Harmonic Motion Simulation 3A Simple Harmonic Motion 3b Period Frequency Amplitude Restoring Force Phase 3 Summary 4 Resonance 4a Resonance Examples Simulation 4A Resonance Resonance and Tidal Bores in the Bay of Fundy 4b A Few Other Examples of Resonance Simulation 4B Resonance in a Chain 4 Summary 5 Wave Types 5a Transverse Waves Simulation 5A Transverse Waves 5b Longitudinal Waves Simulation 5B Longitudinal Waves 5c Torsional Waves 5d Examples of Waves Simulation 5C Water Waves The Electromagnetic Spectrum 5 Summary 6 Wave Speed 6a Speeds of Different Types of Waves Simulation 6A Wave Speed 6 Summary 7 Wave Behavior 7a Reflection Simulation 7A Reflection 7b Refraction Simulation 7B Refraction Simulation 7C Lenses Simulation 7D Dispersion 1 Simulation 7E Dispersion of a Square Wave 7c Adding Waves Simulation 7F Adding Wave Pulses Simulation 7G Adding Sine Waves 7d Interference Simulaton 7H Path Difference Simulation 7I Interference 7e Diffraction Simulation 7J Diffraction 7f Doppler Shift Simulation 7K Doppler Shift 7 Summary 8 Pitch 8a Pitch 8b Loudness 8c Just Noticeable Difference 8d Timbre The First Time 8 Summary 9 Fourier 9a Wave Shape 9b Fourier Series Simulation 9A Fourier Synthesis 9c Fourier Analysis 9d Timbre Again 9 Summary 10 Perception 10a Structure of the Ear Detailed Structure of the Ear 10b The Place Theory of Hearing 10c The Temporal Theory of Hearing 10d Hearing Loss 10E Auditory Illusions Other Interesting Auditory Phenomena 10 Summary 11 Strings 11a String Resonance Simulation 11A String and Tube

    Original URL path: https://soundphysics.ius.edu/?page_id=923 (2016-02-01)
    Open archived version from archive

  • 9. Fourier | SOUND
    Harmonic Motion Simulation 3A Simple Harmonic Motion 3b Period Frequency Amplitude Restoring Force Phase 3 Summary 4 Resonance 4a Resonance Examples Simulation 4A Resonance Resonance and Tidal Bores in the Bay of Fundy 4b A Few Other Examples of Resonance Simulation 4B Resonance in a Chain 4 Summary 5 Wave Types 5a Transverse Waves Simulation 5A Transverse Waves 5b Longitudinal Waves Simulation 5B Longitudinal Waves 5c Torsional Waves 5d Examples of Waves Simulation 5C Water Waves The Electromagnetic Spectrum 5 Summary 6 Wave Speed 6a Speeds of Different Types of Waves Simulation 6A Wave Speed 6 Summary 7 Wave Behavior 7a Reflection Simulation 7A Reflection 7b Refraction Simulation 7B Refraction Simulation 7C Lenses Simulation 7D Dispersion 1 Simulation 7E Dispersion of a Square Wave 7c Adding Waves Simulation 7F Adding Wave Pulses Simulation 7G Adding Sine Waves 7d Interference Simulaton 7H Path Difference Simulation 7I Interference 7e Diffraction Simulation 7J Diffraction 7f Doppler Shift Simulation 7K Doppler Shift 7 Summary 8 Pitch 8a Pitch 8b Loudness 8c Just Noticeable Difference 8d Timbre The First Time 8 Summary 9 Fourier 9a Wave Shape 9b Fourier Series Simulation 9A Fourier Synthesis 9c Fourier Analysis 9d Timbre Again 9 Summary 10 Perception 10a Structure of the Ear Detailed Structure of the Ear 10b The Place Theory of Hearing 10c The Temporal Theory of Hearing 10d Hearing Loss 10E Auditory Illusions Other Interesting Auditory Phenomena 10 Summary 11 Strings 11a String Resonance Simulation 11A String and Tube Standing Waves 11b Surface Resonances 11c Volume or Helmholtz Resonance 11d Stringed Instruments 11 Summary 12 Tubes 12a Tube Resonance 12b Impedance Simulation 12B Reflection from Boundaries Simulation 12c Mechanical Impedance 12c Woodwind Instruments 12d Brass Instruments 12e Pipe Organs and Other Reed Instruments 12 Summary 13 Percussion 13a Instruments with Non harmonic Overtones 13b Harmonic Percussion

    Original URL path: https://soundphysics.ius.edu/?page_id=59 (2016-02-01)
    Open archived version from archive

  • 9a: Wave Shape | SOUND
    waves drive the motion of tiny styrofoam balls Why do they form into the shapes that you see There are also smart phone apps that will show the shape of a sound wave in real time for example SignalScope or oScope for the iPhone or SpecScope for Android 1 Introduction 2 Basics 2a Motion and Force 2b Newton s Three Laws Forces Simulation 2c Density and Pressure 2d Energy and Power 2e Two Energy Laws Simulation 2D Energy Conservation in a Spring 2 Summary 3 Vibration 3a Simple Harmonic Motion Simulation 3A Simple Harmonic Motion 3b Period Frequency Amplitude Restoring Force Phase 3 Summary 4 Resonance 4a Resonance Examples Simulation 4A Resonance Resonance and Tidal Bores in the Bay of Fundy 4b A Few Other Examples of Resonance Simulation 4B Resonance in a Chain 4 Summary 5 Wave Types 5a Transverse Waves Simulation 5A Transverse Waves 5b Longitudinal Waves Simulation 5B Longitudinal Waves 5c Torsional Waves 5d Examples of Waves Simulation 5C Water Waves The Electromagnetic Spectrum 5 Summary 6 Wave Speed 6a Speeds of Different Types of Waves Simulation 6A Wave Speed 6 Summary 7 Wave Behavior 7a Reflection Simulation 7A Reflection 7b Refraction Simulation 7B Refraction Simulation 7C Lenses Simulation 7D Dispersion 1 Simulation 7E Dispersion of a Square Wave 7c Adding Waves Simulation 7F Adding Wave Pulses Simulation 7G Adding Sine Waves 7d Interference Simulaton 7H Path Difference Simulation 7I Interference 7e Diffraction Simulation 7J Diffraction 7f Doppler Shift Simulation 7K Doppler Shift 7 Summary 8 Pitch 8a Pitch 8b Loudness 8c Just Noticeable Difference 8d Timbre The First Time 8 Summary 9 Fourier 9a Wave Shape 9b Fourier Series Simulation 9A Fourier Synthesis 9c Fourier Analysis 9d Timbre Again 9 Summary 10 Perception 10a Structure of the Ear Detailed Structure of the Ear 10b The Place

    Original URL path: https://soundphysics.ius.edu/?page_id=935 (2016-02-01)
    Open archived version from archive

  • 9b: Fourier Series | SOUND
    square wave any periodic shape can be formed by adding sine waves This is the concept behind constructing an electronic instrument called a synthesizer Electric pianos also use this principle By combining the right frequencies and amplitudes of sine and cosine waves the synthesizer can duplicate the sound wave of any other instrument The exact electronics that do this are somewhat complicated but the principle is simple the right combination of sine waves can create the sound of any musical instrument NOTE Modern synthesizers also often use digitally recorded samples of instruments or other sounds which are electronically modified for output in addition to pure sine and cosine waves 1 Introduction 2 Basics 2a Motion and Force 2b Newton s Three Laws Forces Simulation 2c Density and Pressure 2d Energy and Power 2e Two Energy Laws Simulation 2D Energy Conservation in a Spring 2 Summary 3 Vibration 3a Simple Harmonic Motion Simulation 3A Simple Harmonic Motion 3b Period Frequency Amplitude Restoring Force Phase 3 Summary 4 Resonance 4a Resonance Examples Simulation 4A Resonance Resonance and Tidal Bores in the Bay of Fundy 4b A Few Other Examples of Resonance Simulation 4B Resonance in a Chain 4 Summary 5 Wave Types 5a Transverse Waves Simulation 5A Transverse Waves 5b Longitudinal Waves Simulation 5B Longitudinal Waves 5c Torsional Waves 5d Examples of Waves Simulation 5C Water Waves The Electromagnetic Spectrum 5 Summary 6 Wave Speed 6a Speeds of Different Types of Waves Simulation 6A Wave Speed 6 Summary 7 Wave Behavior 7a Reflection Simulation 7A Reflection 7b Refraction Simulation 7B Refraction Simulation 7C Lenses Simulation 7D Dispersion 1 Simulation 7E Dispersion of a Square Wave 7c Adding Waves Simulation 7F Adding Wave Pulses Simulation 7G Adding Sine Waves 7d Interference Simulaton 7H Path Difference Simulation 7I Interference 7e Diffraction Simulation 7J Diffraction

    Original URL path: https://soundphysics.ius.edu/?page_id=945 (2016-02-01)
    Open archived version from archive

  • Simulation 9A: Fourier Synthesis | SOUND
    Different Types of Waves Simulation 6A Wave Speed 6 Summary 7 Wave Behavior 7a Reflection Simulation 7A Reflection 7b Refraction Simulation 7B Refraction Simulation 7C Lenses Simulation 7D Dispersion 1 Simulation 7E Dispersion of a Square Wave 7c Adding Waves Simulation 7F Adding Wave Pulses Simulation 7G Adding Sine Waves 7d Interference Simulaton 7H Path Difference Simulation 7I Interference 7e Diffraction Simulation 7J Diffraction 7f Doppler Shift Simulation 7K Doppler Shift 7 Summary 8 Pitch 8a Pitch 8b Loudness 8c Just Noticeable Difference 8d Timbre The First Time 8 Summary 9 Fourier 9a Wave Shape 9b Fourier Series Simulation 9A Fourier Synthesis 9c Fourier Analysis 9d Timbre Again 9 Summary 10 Perception 10a Structure of the Ear Detailed Structure of the Ear 10b The Place Theory of Hearing 10c The Temporal Theory of Hearing 10d Hearing Loss 10E Auditory Illusions Other Interesting Auditory Phenomena 10 Summary 11 Strings 11a String Resonance Simulation 11A String and Tube Standing Waves 11b Surface Resonances 11c Volume or Helmholtz Resonance 11d Stringed Instruments 11 Summary 12 Tubes 12a Tube Resonance 12b Impedance Simulation 12B Reflection from Boundaries Simulation 12c Mechanical Impedance 12c Woodwind Instruments 12d Brass Instruments 12e Pipe Organs and Other Reed Instruments

    Original URL path: https://soundphysics.ius.edu/?page_id=949 (2016-02-01)
    Open archived version from archive



  •