Page 38 - Fall2021

ROOM ACOUSTICS DESIGN OF WORSHIP SPACES
use of any electronic sound reinforcement was a formi- dable challenge. As is typical for Orthodox synagogues, there are two sound source locations that require natural reinforcement. The opportunity to improve natural rein- forcement of speaking and chanting was limited to the ceiling design. Figure 6 shows how the proposed ceiling design provides the needed reflections into the seating area from both sound production locations; Figure 7 shows the built interior of the Young Israel of Greater Cleveland synagogue.
Acoustical Support of Congregational Participation in Worship
Some spaces have acoustical environments that encour- age congregants to sing and participate in a worship service by reciting responsive prayers or by singing. Although, in general, more reverberant rooms provide better support of congregational participation than less reverberant rooms, the correlation between reverberation time and acoustical support of congregational singing is poor. Reverberation level correlates more strongly. The reverberation level is generally higher in smaller rooms than in larger rooms, whereas the reverberation time is generally higher in larger rooms than in smaller rooms. Consequently, smaller worship spaces generally provide better acoustical support of congregational participation than larger rooms.
As rooms get larger, the surface closest to the congregation (the floor) becomes the most important sound-reflecting surface to support congregational participation. Choir and music directors know from experience that carpet- ing is the worst thing to have on the floor to support congregational participation.
Acoustical support of congregational participation is a very dynamic phenomenon based on the known tendency of people to speak or sing more loudly to be heard as others around them do the same. In a worship space, if a congregant hears other congregants singing, he or she will feel comfortable singing more loudly. This encourages fellow congregants, in turn, to sing more loudly. This can result in a swell of energy that meets the goal of supporting congregational participation.
Conversely, in gathering spaces like restaurants, where the goal is to minimize the swell of energy to allow diners
to communicate with a minimum of effort, carpeting is essential (see Roy and Siebein, 2019). Restaurants with sound-reflective floors, almost regardless of other wall and ceiling finishes, are often unpleasant spaces in which to have a meal due to the loudness of conversations at other tables. In other words, the acoustical goals for the design of a space to support congregational participation is exactly the oppo- site of the goal for the acoustical design of a restaurant.
Next to the floor finish, the ceiling is often the next clos- est surface to the congregation (compared with the walls) for a large majority of congregants. Therefore, in general, when sound absorption is required to control excessive reverberation in a worship space, it is best to incorporate sound absorption on the walls and not on the ceiling.
Some very large worship spaces use electronic enhance- ment (also called electronic architecture) systems to enhance acoustical support of congregational par- ticipation. These systems typically have arrays of ceiling-suspended loudspeakers that electronically add sound energy into the congregational seating area so that congregants hear themselves and other congregants more loudly, which encourages them to participate.
The Stonebriar Community Church north of Dallas, Texas, is one of several examples of churches that incorporated an electronic architecture system. These systems are rarely used in worship spaces but are fre- quently added to spaces for music performance that have compromised acoustics. Stonebriar’s natural acoustics were designed to support their amplified praise band and, as a result, were not ideal for choral and orchestral music, styles used for their traditional services. Furthermore, congregational participa- tion was a high priority for this church. To enhance their traditional service and to improve the acous- tical support of congregational singing, Stonebriar added a separate electronic architecture system. In this arrangement, microphones hang both over the musicians’ area and the congregation. That signal is processed and played back through an array of speak- ers that are suspended from the ceiling, pointing down toward the musicians’ area and the congregation. The additional reverberant sound energy these speakers provide in the congregational area encourages people to participate in the worship service.
38 Acoustics Today • Fall 2021