1 General
1.1 Scope
1.2 References
1.3 Terms and definitions
1.4 Abbreviations
1.5 Conventions
2
Overview of subjective testing procedures for Echo Cancellers
2.1 Conversational test
2.2 Talking-and-listening test
2.3 Third-Party listening tests
3
General considerations for subjective evaluation of echo cancellers
3.1 Echo canceller parameters to evaluate
3.2 Test equipment and calibration
3.3 Selection of subjects
3.4 Analysis of results
4
Conversation tests
4.1 Purpose
4.1.1 Advantages
4.1.2 Disadvantages
4.2 Test design, set-up and procedure
4.2.1 Test design and circuit conditions
4.2.2 Reference conditions
4.2.3 Task
4.2.4 Opinion scales and questionnaires
5
Talking-and-listening test
5.1 Purpose
5.2 Parameters
5.3 Set-up
5.4 Description of test procedure
5.4.1 Initial convergence
5.4.2 Steady state conditions
5.5 Advantages
5.6 Disadvantages
5.7 Reference conditions
5.8 Precautions
6
Third-party listening Test A
6.1 Purpose
6.2 Parameters
6.3 Set-up
6.4 Recording procedure for original source material
6.5 Recording procedure for listening test material
6.6 Description of the listening test procedure
6.6.1 Playback
6.6.2 Subjects
6.7 Advantages
6.8 Disadvantages
6.9 Reference conditions
6.10 Precautions
7
Third-party listening Test B
7.1 Purpose
7.2 Impairments to evaluate
7.3 Set-up
7.4 Advantages
7.5 Disadvantages
7.6 Reference conditions
7.7 Precautions
7.8 Description of test procedure
7.8.1 Recording
7.9 Evaluation
7.9.1 Playback
7.9.2 Subjects
Annex A – Questionnaires for use in conversational tests
A.1 Introduction
A.2 Sample questions
Appendix I – Example test conditions for echo canceller evaluations