Adopts ISO 354:2003 to specify a method of measuring the sound absorption coefficient of acoustical materials used as wall or ceiling treatments, or the equivalent sound absorption area of objects, such as furniture, persons or space absorbers, in a reverberation room.
Table of contents
Header
About this publication
Preface
Introduction
1 Scope
2 Normative references
3 Terms and definitions
4 Principle
5 Frequency range
6 Test arrangement
6.1 Reverberation room and diffusion of sound field
6.1.1 Volume of reverberation room
6.1.2 Shape of reverberation room
6.1.3 Diffusion of the sound field
6.1.4 Sound absorption area
6.2 Test specimens
6.2.1 Plane absorbers
6.2.1.1
6.2.1.2
6.2.1.3
6.2.2 Discrete sound absorbers
6.2.2.1
6.2.2.2
6.2.2.3
6.3 Temperature and relative humidity
6.3.1
6.3.2
7 Measurement of reverberation time
7.1 General
7.1.1 Introduction
7.1.2 Microphones and microphone positions
7.1.3 Source positions
7.1.4 Number of microphone and loudspeaker positions
7.2 Interrupted noise method
7.2.1 Excitation of the room
7.2.2 Averaging
7.2.3 Recording system
7.3 Integrated impulse response method
7.3.1 Direct method
7.3.2 Indirect method
7.3.3 Recording system
7.3.4 Integration of the impulse response
7.4 Evaluation of reverberation times based on decay curves
7.4.1 Evaluation range
7.4.2 Evaluation method
8 Expression of results
8.1 Method of calculation
8.1.1 Calculation of reverberation times T1 and T2
8.1.2 Calculation of A1, A2 and AT
8.1.2.1
8.1.2.2
8.1.2.3
8.1.3 Calculation of αs
8.1.4 Calculation of equivalent sound absorption area of discrete absorbers
8.2 Precision
8.2.1 General
8.2.2 Repeatability of measured reverberation times
