ISO 532 - Living and working with alternative loudness standards

By its very nature, standardization claims to set u nique rules and procedures, thus aiming unique, i.e . comparable and reproducible results. Also, to be effecti ve, the standard and the underlying approach need t o be broadly accepted by the addressed user community. To come up with such general agreement it is typical ly required that a “best” approach, covering all relev ant applications of interest, has been established. If this does not apply, the existence of alternative standa rds in parallel may offer a way out. The revision process of ISO 532 “Acoustics ‐ Methods for calculating loudness” showed that it was not possible to prove and agree on a single “best” appr oach. Acknowledging the legitimate demand of applicative continuity, the member bodies of ISO TC 43 “Acoustics” therefore decided to maintain the given situati on by specifying two alternative approaches again. With r eference to existing national standards (DIN 45631/ A1 and ANSI S3.4), these are the Zwicker approach in an extended version for time-varying sounds and the Moore/Glasberg approach for stationary sounds at fi rst. Based on a review of the revision process and a sum marizing justification of the resulting decision, t he discussion of practical and theoretical consequences o f the renewed dualism will outline the chances for broader applications of loudness calculations. However, thi s dualism also establishes the commitment to thorou ghly identify and seize the chance for final unification of the standard.