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This document was prepared by Technical Committee ISO/TC 43, Acoustics, Subcommittee SC 2, Building acoustics.

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The acoustic properties of a room are crucial for the interaction between the room and the musical instrument. When the acoustic response of a room works well with the instrument, good conditions are achieved for both audience and musicians.

There is a clear connection between the intended use of a music room, the type of music, the ensemble type and the size of the room. It is not possible to achieve satisfactory acoustic conditions for all music types and speech communication in a single room since the acoustic requirements for each use are different.

It is necessary to divide the spaces in accordance with their function and number of musicians or singers (both amateurs and professionals). There are different needs when it comes to the physical size of the room (net volume), timbre, reverberation, net room height and room geometry. The division into types of rooms in this document reflects the practical conditions in musical performance. The musicians play or sing individually (rehearsing or receiving teaching), in small groups (either with the same instruments, voices or in ensembles of three to six persons), in medium size groups/ensembles or in large groups/ensembles (choirs, marching bands, big bands, orchestras and other ensembles), see Reference [22].

The document describes criteria for any kind of rooms and spaces used for music rehearsal. The rooms used for music purposes vary from small practice rooms for one or a few musicians to very large rehearsal rooms and concert halls. In large concert halls, skilled acousticians are engaged for designing and planning the acoustics. In the practice rooms and rooms used for rehearsal or more unformal music performances, the acoustic environment is often not suited for this purpose.

This document is intended for municipalities and county councils, property developers, builders, consultants, architects, contractors, facility owners (public and private) and others who operate or own such buildings. The document may also be used by others, from the individual musician to large groups and associations. A large number of rooms and spaces are used for music rehearsal and performance in municipalities. It is important for property developers to emphasise participation by typical users of the building and the music rooms as early as possible, preferably during the conceptual or planning stages, of which this document should form one of the premises.

Annex A provides guidelines for determining the sound pressure level at forte applying the sound strength (G) of the room and the average sound power level at forte of the musical instruments in question. This leads to favourable range of net room volume and reverberation time for a certain ensemble type. Annex B provides guidelines concerning user processes for planning of rooms for music rehearsal.