Volume 104, Issue 1, July 1998
Index of content:
- ARCHITECTURAL ACOUSTICS 
Relations among interaural cross-correlation coefficient lateral fraction and apparent source width (ASW) in concert halls104(1998); http://dx.doi.org/10.1121/1.423955View Description Hide Description
Relations are determined between one of the important subjective attributes of concert hall acoustics, the apparent source width, ASW, and three acoustical measures, interaural cross-correlation coefficient and strength factor Although these measures previously have been found to correlate with ASW, their relations with it have not been examined sufficiently, especially in respect to their frequency characteristics. Herein, ASW’s are directly determined for electronically reproduced musical sound fields with extensive ranges of values for and Investigated as parameters are angles of incidence, the time delay difference between a pair of symmetric early lateral reflections, and the number of early lateral reflections. These studies indicate the relative efficacy of and for determining ASW under conditions that are realistically encountered in concert halls. The results were compared with measured’s, ’s, and also the strength factor ’s in existing concert halls. It is concluded that the arithmetic average of ’s at 500, 1 k and 2 k Hz combined with the strength factor of the sound field at frequencies below 250 Hz are physical measures highly correlated with the subjective rank ordering of concert halls and that they cover the effects on ASW of the entire octave-band frequency range from 125 to 4 k Hz.
104(1998); http://dx.doi.org/10.1121/1.423277View Description Hide Description
The results of a systematic study investigating the effect on the sound insulation of wood stud walls having penetrations made by electrical outlet boxes are presented. The effect on sound insulation is shown to be almost negligible, regardless of box separation, if the boxes are themselves airtight and form an airtight seal with the gypsum board surfaces. However, if the boxes are not airtight, then the degradation to the sound insulation is strongly dependent on the separation between the boxes. Other significant factors include the presence of cavity absorption, and its method of installation. A series of retrofits for poorly installed boxes is examined and show that commonly available devices for reducing airflow (and sound insulation) through electrical boxes can be very effective but are highly dependent on installation.