Electroacoustics 1

• 26 hrs lectures
• 4 hrs exercises
• 22 hrs laboratories
• 13 hrs projects

The aim of the course is to make students familiar with the chain of processing acoustic signals from their origination through their transformation into electric signals and back to acoustic signals up to the listener's final perception.
On completion of the course, students are able to:
- enumerate the basic acoustic quantities and their units,
- explain the physiology of hearing, including binaural auditory perception,
- employ sound level meters and use them for noise and electro-acoustic measurements,
- describe room acoustic properties, demonstrate the measurement of room impulse response and reverberation time, enumerate materials and structures used for modifying the room acoustics
- categorize electro-acoustic transducers and state their principles, properties and use,
- categorize microphones, state their properties and designs, and demonstrate the measurement of their characteristics,
- describe the properties of designs used for unloaded and loaded loudspeakers, measure and calculate their parameters,
- design loudspeaker systems and measure their characteristics,
- enumerate the types of surround sound systems and describe their principle.

The knowledge of basic physical laws is required as well as the knowledge of laws and quantities in electrical circuits, characteristics of electric circuit elements, circuit behaviour with inertia elements, periodical and non-periodical signal spectra, random variables and basic terms from the area of statistics. Students who enrol on the course should be able to use instruments for the measurement of electrical voltage, current, and resonant frequency, waveform generators, and oscilloscopes.

• Colloms, M., High Performance Loudspeakers, 6th ed. John Wiley & Sons, Ltd, 2005. ISBN 978-0-470094-30-3
• Zwicker, E., Fastl, H. Psychoacoustics, Facts and Models, 2nd ed. Springer-Verlag, 1999. ISBN 3-540-65063-6
• Streicher, R., Everest, F., A. The New Stereo Soundbook, 3rd ed. Audio Engineering Associates, 2006. ISBN 978-0-9665162-1-0

1. Sound waves: sound propagation, sound field quantities, wave equation of sound propagation, basic types of sound waves, types of sound fields.
2. Physiological and psychological acoustics: auditory organ, subjective perception of sound waves, sound masking and its use for lossy sound coding, directional and spatial hearing.
3. Measurement of acoustic quantities: time and frequency weighting filters, constante percentace bandwidth analysis, statistical analysis, noise measurement, loudness measurement.
4. Sound level meter: construction of the sound level meter and the function of its individual parts, calibration of the measuring chain, measurement uncertainty.
5. Room acoustics: propagation of sound in the environment, solution of the wave equation in a closed space, modeling of acoustic spaces, reverberation time and its measurement, room impulse response and its measurement, acoustic structures.
   
6. Electromechanical and electroacoustic analogy: mechanical translation systems, acoustic systems.
7. Electromechanical transducers: transducer as a system, transducers using electrostatic and electromagnetic fields.
8. Microphones: acoustic receivers, directional receivers, model of microphone, construction of microphones, electrical interface of microphones, parameters of microphones and their measurements.
9. Loudspeakers: acoustic transmitters, electrodynamic loudspeaker and its model, electrostatic, piezoelectric and ribbon direct radiating loudspeaker, indirect radiating loudspeakers, loudspeaker parameters and their measurements.
10. Loudspeaker systems: semi-closed, closed and bass-reflex enclosures, band-pass type enclosures, loudspeaker crossovers, construction of loudspeaker systems, loudspeaker system parameters.
11. Headphones: types of headphones, model of headphones and simulation of acoustic impedance of the ear, construction of headphones, parameters of headphones and their measurements.
12. Basics of sound system design: sound systems for small rooms, stereophonic and multi-channel reproduction, surround sound and immersive audio, sound systems for large spaces, acoustic feedback and its suppression. 

• Logarithmic quantities, sound waves 
• Addition and subtraction of levels of acoustic quantities

• Getting familiar with the laboratory, work with Excel, test from numerical exercises
• Task No. 1 – Noise measurement
• Task No. 2 – Measurement of reverberation time
• Task No. 3 – Measurement of microphone characteristics
• Task No. 4 – Measurement of headphone characteristics
• Task No. 5 – Measurement of characteristics of communication devices
• Task No. 6 – Measurement of speaker distortion
• Task No. 7 – Measurement of TS parameters of loudspeaker
• Task No. 8 – Design of a loudspeaker system
• Task No. 9 – Measurement of loudspeaker systemcharacteristics
• Alternate term for measurement, test from laboratory exercises 

• Calculation of loudness  from measured values
• Calculation of reverberation time from measured values
• Calculation of parameters of studio microphone from measured values
• Calculation of earphone from measured values
• Calculation of headset parameters from measured values
• Calculation of speaker distortion from measured values
• Calculation of TS loudspeaker parameters from measured values
• Calculation of the volume of the speaker enclosure and frequency crossover of the speaker system
• Calculation of loudspeaker parameters from measured values 

Evaluation of study results follow the BUT Rules for Studies and Examinations and Dean's Regulation complementing the BUT Rules for Studies and Examinations. Up to 22 points are awarded for the tests in theoretical knowledge in the exercises. Up to 18 points can be obtained for correct results and elaboration of all laboratory exercises. Up to 40 points are given for the test part of the final examination, and it is necessary to get at least 20 points for its successful completion. Up to 20 points are given for the written part of the final examination and it is necessary to get at least 10 points for its successful completion.

Credit is awarded for completing all laboratory tasks and their fulfillment to a minimum extent, completing all numeric exercises and obtaining 50% of the points from the test from the numeric exercises. The minimum scope of fulfillment of individual laboratory tasks are specified by a regulation issued by the guarantor of the course and updated for every academic year. 

In the case of distance learning, tests in practice are performed remotely in e-learning and laboratory excercises are replaced by homework evaluated with the same number of points. The exam will take place in person, in justified cases remotely.