Acoustics of Studios

Figure 5. Acoustic power required for full reproduction of speech and music in rooms of various sizes. This assumes optimum reverberation time and average noise conditions (Reference 5).

Certain complex and intangible subjective effects such as tonal "brilliance," "brightness", and "liveness" must be considered in the design of broadcast and sound-recording studios.^15,16,17,18 Studios have been designed with "live" ends and "dead" ends. The live end contains little sound-absorbing material, and the musicians usually occupy this portion, so that the proper blending of the musical sounds is attained. The microphone is placed in the dead end, which is provided with much sound-absorbing material so that little reflection occurs. The modern tendency is not to concentrate the sound-absorbing material at a given area, but to spread it more or less throughout the room. Certain surfaces are often constructed of convex plywood "cylinders." These have absorbing properties at certain frequencies and also tend to vibrate and enhance certain frequencies.¹⁷ Also, curved and non-parallel surfaces tend to prevent multiple reflection of certain frequencies from surface to surface that might result in "flutter." Studios are usually approximately rectangular with the provision, previously mentioned, that the surfaces are broken up with convex surfaces, or in other ways. To prevent the transmission of vibrations, and the entrance of sound from outside sources, studios are usually "floated" so that they are effectively isolated from the rest of the build-ing.^{5, 10} Air ducts for heating and ventilating must be carefully designed so that they do not convey sounds into the studio.