Overview
IEC 62777:2016 defines a quality evaluation method for the sound field of directional loudspeaker array systems. The standard establishes a uniform way to describe and measure the audio space around a person (the personal acoustic zone, PAZ) and to quantify how effectively directional loudspeaker arrays deliver focused sound without disturbing nearby listeners. It specifies the characteristics useful for product specification and provides measurement methods to compare system types and determine appropriate practical applications.
Key topics and technical requirements
- Personal acoustic zone (PAZ) - an acoustic volume occupied by a listener described by width (W), depth (D) and height (H). PAZ dimensions and the standard personal distance between listeners are to be stated.
- Sound pressure level measurement - sound pressure is measured at the centers of the PAZ surfaces (six points) and averaged to produce the PAZ average sound pressure level.
- Personal Acoustic Zone Index (PAZI) - a family of indices that quantify directivity and isolation of the personal audio space:
- PAZI-x, PAZI-y, PAZI-xy, PAZI-xyz - ratios comparing the target listener’s PAZ average sound level to sums of levels at other positions (e.g., front, front-right, rear), enabling standard comparisons of beamforming effectiveness.
- Measurement method elements - directional loudspeaker array setup, microphone placement, test signals and measurement of sound pressure level curves. The standard also specifies test environment conditions such as temperature and humidity to ensure reproducible results.
- Instrument standards - references to related instrument and loudspeaker standards (e.g., IEC 60268-series, IEC 61672-1) are normative for correct application.
Practical applications and users
IEC 62777 is intended for:
- Product designers and acoustic engineers developing directional loudspeaker arrays and beamforming systems for consumer electronics (smartphones, tablets, TVs, computers, game consoles).
- Manufacturers and QA/test labs requiring reproducible measurement methods and specification criteria for personalized audio products.
- Acoustic consultants and integrators specifying systems for public venues (museums, exhibitions, shopping malls, fitness clubs) where localized audio delivery is needed without headphones.
- Standards bodies and procurement teams comparing products by a consistent metric (PAZI and PAZ sound pressure levels).
Practical outcomes include standardized product datasheets, performance comparisons between directional-array implementations, and informed selection of systems for target personal distances and use environments.
Related standards
Keywords: directional loudspeaker array, personal acoustic zone, PAZ, PAZI, sound pressure level, measurement methods, audio quality evaluation, beamforming.