In chapters 1 and 3 of this white paper, definitions are proposed to support discussions on audio quality and sound quality. Chapter 8 presented a selection of issues on operational quality. For discussions to make sense, in addition to definitions, information about the audio system is required - including judgement statements on the audio quality, sound quality and operational quality. Operational quality is generally covered by comparing the published system devices and the system design’s operational specifications to the operational requirements. For the audio quality and sound quality however, things are a little more complicated. The assessment of both audio quality and sound quality is a subject of discussions in the professional audio market(*9A). Contributing to the discussions from a ‘Performance & Response’ viewpoint, this chapter presents two basic methods for the quality assessment of an audio system: analysis of electrical measurements, and listening.
9.1 Quality assessment through electronic measurements
9.2 Quality assessment through listening tests
9.3 Conducting listening tests
- 1. Tests must be controlled: all factors other than the audio system must be either removed or kept constant:
- * sound source (live musicians can not be used)
- * acoustic environment
- * listening position & angle
- * visible environment
- * temperature and humidity
- * smell and taste
- 2. at least two listening sessions must be performed per listening test to allow differential analysis.
- * A single session referencing to memory is not valid.
- 3. tests must be blind
- * The test subjects must not know to what reference they are listening to
- 4. audio materials must be shorter than 20 seconds
- 5. If different signal chains are used, their total gain must be calibrated within 0.5 dB