ABSTRACT
The starting point of modern room acoustics is marked by attempts to define physical sound field parameters suited to quantify the subjective acoustic impression of a listener sitting in a hall and attending a presentation. With the development and introduction of the electrical amplifier in the 1920s, almost all measuring techniques became electrical. Although the experimenter should have a certain idea of the sensitivity of his microphones, absolute calibration is usually not required since virtually all sound measurements in room acoustics are relative. Room acoustic measurements are necessary for research and design purposes and are also used as a diagnostic tool for existing rooms. Suppose there are frequent and persistent complaints about the acoustics of a particular hall. According to system theory, all properties of a linear transmission system are contained in its impulse response or, alternatively, in its transfer function, which is the Fourier transform of the impulse response.
