One of the core performance parameters in CEDIA/CTA-RP22 Immersive Audio Design Recommended Practice is SPL capability. It is often discussed and misunderstood, along with the so-called reference level for listening. In commercial cinema, a reference SPL has long been established and consistently applied to match post-production to intended playback levels in exhibition cinemas. But in private entertainment spaces there's far greater variability in the range and type of source media, type and size of rooms, scope and capability of audio systems, and perception of loudness.  

This white paper explores what reference audio level means both for commercial and home consumer content, the many facets of loudness perception, and clarifying the SPL recommendations as set out in RP22.