Audio

This lecture is oriented towards the study of audio engineering, with a special focus on room acoustics applications. The learning outcomes will be the techniques for microphones and loudspeaker design, sound radiation and acoustic antenna principles, as well as room acoustics knowledge.

(click on the hyperlinks to download the presentations)

Outline of the semester:

Support books

General topics

• M. Rossi, Audio, Presses Polytechniques et Universitaires Romandes, 2007
• V. Martin, Elements d'acoustique générale, PPUR, 2007
  
• J. Blauert, N. Xiang, Acoustics for engineers, Springer 2009

• H. Kuttruff, Room acoustics, Spon Press, 2009

Online resources

• MOOCS on Electroacoustics (in English)
• MOOCS on Electroacoustique (in French)
  

Lexicon of the lecture

Chapter II: Hearing

1. The anatomy of the ear
   
2. An introduction to psychoacoustics
   
3. Noise and its effects

Additional links:

• SUVA documentation on Music and Troubles of Hearing (French, German, Italian)
• World Health Organization report: "Burden of disease from environmental noise" (2011)
• ADEME report:"Coût social du bruit en France" (2021) (French)
  
• FOEN: Répercussions économiques du bruit en Suisse (2020) (French, German, Italian)
  

Chapter III: Room acoustics

1. Wave theory of room acoustics
2. Geometrical room acoustics
3. Statistical room acoustics

Chapter IV: Electroacoustic systems and transducers

1. Electroacoustic analogies
   
2. Electromechanical transducers:
   1. Electrodynamic transduction
   2. Electrostatic transduction
   3. Plasma loudspeakers
      
3. Sound radiation principles
   
4. Acoustic antenna and arrays

Chapter V: Microphones and loudspeakers design

1. Microphone theory and design
2. The electrodynamic loudspeaker
3. Loudspeaker systems

• notes on how to derive the power radiated by loudspeaker systems (closed-box and vented-box)
• Richard Small's paper on loudspeaker system analysis
• Richard Small's paper on loudspeaker system synthesis

• Chapter 2.2: 1-Introduction

• Chapter 2.2: 2-Loudness and Sound Pressure Level

• Chapter 2.2: 3-Pitch and Frequency

• Chapter 2.2: 4-Masking

Important note:

This lecture is a reminder of what is considered a prerequisite for the following lectures on microphones and loudspeakers design. Therefore, I will go very quickly to cover what takes several weeks at Bachelor's level. To further understand the following video presentations, I advise that you read Chapters 2 and 3 (for electroacoustic analogies), and Chapters 5 and 6 (for electromechanical transductions) of the book Acoustics for Engineers by J. Blauert and N. Xiang, or alternatively, Chapter 6 (electroacoustic analogies) and 7 (electromechanical transducers) of the book Audio by M. Rossi.

Chapter IV.1: Electroacoustic analogies

Note:

Radiation of sources

Illustrations with COMSOL Multiphysics - tutorial

Chapter 4.4: Antenna and arrays

Illustrations with COMSOL Multiphysics - tutorial

1. The Uniform Linear Antenna

2. The Phased Linear Antenna

Chapter 5.1: Microphones theory and design

Chapter 5.2: Electrodynamic loudspeaker

• Chapter 5.2: 1-Introduction

• Chapter 5.2: 2-Electrodynamic loudspeaker acoustic scheme

• Chapter 5.2: 3-Electrodynamic loudspeaker electric scheme

• Chapter 5.2: 4-Thiele-Small parameters

• Chapter 5.2: 5-Acoustic response

• Chapter 5.2: 6-Electric response and high-frequency behaviour

Chapter 5.3: Loudspeaker systems (w/ enclosures)

Seminar: Electroacoustic absorbers

1. Introduction

2. Control design

3. Performance optimization

4. Performance evaluation and conclusions

Forum Acusticum 2020 presentation:

• Experimental assessment of a broadband perfect absorber for use as anechoic termination

1. Introduction

2. Frequency response of the room

3. Spatial distribution of pressure in the room

4. Time decay of room modes

Dear students,

here's the exam of this year and its hand-written corrections. I just figured out there was a typo on the answer of Question Q7 (the good answer was 100.8 ~101 dB instead of 100 dB). Sorry for that.

I wish you all the best for the following. Regards,

Hervé Lissek