The transmission loss and vibration of glass panels in non-reverberative conditions

In the usual method of measurement, the structure is placed between two semi-reverberant rooms and diffuse sound fields are used. This paper describes measurements made in conditions of high absorption, with a single directional source. Thus the results should be of value where information on the insulation of glass panels is required for use in high absorption environments, such as recording studios or anechoic laboratories. Microphone measurements are compared with the predicted transmission loss from a capacitive transducer and the effect of sealing the panels is described. Both the microphone measurements and the corrected transducer results are in good agreement with the mass law. The improvement obtained by sealing is an average of about 6dB but large increases in insulation are found at low frequencies. The velocity amplitude is lower than the theoretical value.