RECOMMENDATION ITU-R BS.1534-1 - Method for the subjective assessment of intermediate quality level of coding systems Annex 1 1 Introduction 2 Scope, test motivation and purpose of new method 3 Experimental design 4 Selection of subjects 4.1 Criteria for selecting subjects 4.2 Size of listening panel 5 Test method 5.1 Description of test signals 5.2 Training phase 5.3 Presentation of stimuli 5.4 Grading process 5.5 Recording of test sessions 6 Attributes 6.1 Monophonic system 6.2 Stereophonic system 6.3 Multichannel system 7 Test material 8 Listening conditions 9 Statistical analysis 10 Test report and presentation of results 10.1 General 10.2 Contents of the test report 10.3 Presentation of the results 10.4 Absolute grades 10.5 Significance level and confidence interval References Appendix 1 to Annex 1 - Instructions to be given to subjects 1 Familiarization or training phase 2 Blind grading phase Appendix 2 to Annex 1 - Guidance notes on user interface design