Room acoustics

The room acoustics is an area of acoustics that deals with the impact of the structural conditions of a room on which take place in it sound events.

Focus of the room acoustics is the design of the perceiver quality of sound events by users of concert halls, theaters, assembly halls, classrooms, television and radio studios, churches and other areas where acoustic performances will be made ​​available to a large audience (technical room acoustics ).

The room acoustics it has the properties of human hearing, the peculiarities of speech perception and subjective listening habits and music aesthetics into account ( psychoacoustics ).

Room acoustic design

The acoustic impression of a space is determined by

• Proportion of direct sound at the overall sound level,
• Time delay and direction of early reflections, as well as their share in the overall sound level,
• Use delay and spatial distribution of reverberation, as well as its share of the overall sound level, and the temporal profile ( reverberation time )

Task of room acoustics is to influence these variables by interior design so that the acoustic properties of the room as possible good fit for its intended purpose. Room acoustical design goals can be:

• If possible, no influence of the space in recording studios. This means that the room should be as little reflection, so that the recorded sound is determined only by the direct sound and the acoustic character of the receiving space gets possible not affect the recording.
• The highest possible speech intelligibility in classrooms, lecture halls and theaters. This means that the proportion of the direct sound should be high. Early reflections should come with relatively low use delay primarily from the direction of the speaker to raise the volume of the speaker and to support the localization of the speaker. The reverberation should also start early, but relatively quickly decay ( reverberation time <1 second ) so that it also boosts the volume of the speaker, without reducing the intelligibility of speech.
• A spatial possible music experience of concert halls. This means that the proportion of the direct sound should be balanced against the reflections, large enough to still clear and transparent perceive the music, but not too large so as not to reduce the spatial impression. The early reflections should have a high proportion of overall sound and be as well distributed in terms of direction, so that a possible spatial impression. The reverberation should be spatially well distributed, have a significant share in the overall sound and not too short to surround the listener as well as possible from the music ( reverberation time 1.5 to 2 seconds).

Since the room acoustic properties for different applications are virtually incompatible, it is hardly possible to create a universal space, combining good speech intelligibility and a good spatial music experience. Is this still required, it must either be transformed space depending on the application (eg rearing of heavy curtains in the concert hall in voice performance, creating additional reflecting surfaces in the lecture hall in musical performance ), or the spaces must be sonicated electro- acoustic ( eg distributing of speakers in the lecture hall, which are controlled by corresponding effects devices and so wall reflections and reverberation to simulate ).

Parameters of room acoustics

The best known characteristic of the acoustic space, the reverberation time than the period in which the sound pressure level of a sound event has fallen in a room of 60 dB, to a thousandth part of the initial sound pressure. The reverberation time is generally determined in octave bands or in third-octave bands. If only one reverberation time value is specified, then it is the reverberation time at 1000 Hz or 500 Hz

Target of room acoustics is as good as possible tune a room on its intended purpose and the existing communication scenario.

To design the acoustics of spaces with higher requirements, however, more than just a consideration of the reverberation time is necessary.

So offices are, for example, does not qualify one to be reached on reverberation time. In these rooms, including corridors, counter areas, call centers, libraries and rooms of health care providers are also to count the amount and arrangement of sound-absorbing surfaces of the utmost importance to the listener and the acoustic environment.

The acoustic quality of a room with respect to speech intelligibility is called audibility. To determine the audibility there are standardized intelligibility tests.