Acoustic Quality Evaluation of Voice Booths Using 1/3rd Octave Band Frequency Response

With the establishment of open plan office layouts, the demand for privacy spaces has increased in this type of working spaces, and so has the presence of very small rooms, assigned for phone and video calls. Typically, the volume of these rooms do not exceed 15 m³ and they are commonly occupied by one or two users at the same time. In such small volumes there is a very irregular room response at main frequency bands of regular speech voice due to the modal presence, since the first modes occur at higher frequencies if compared to larger rooms. The modal response also causes a non-uniform sound pressure field over the area, which results in a large deviation of measured parameters for each position, such as reverberation time. This paper studies the validity of a new measurement procedure for obtaining the frequency response of these rooms, based on the difference between the sound power level of the acoustic source and the sound pressure level measured in 1/3rd octave band using a manually-scanned microphone. The results are also compared with numerical methods models in order to verify a possible prediction for a proper acoustic design for the uses of such small rooms.