3pID2 – The Sound of the Sacred: The State of the Art in Worship Space Acoustics – David T. Bradley

The Sound of the Sacred: The State of the Art in Worship Space Acoustics

David T. Bradley – dabradley@vassar.edu
Vassar College
124 Raymond Ave
Poughkeepsie, NY 12604-0745

Erica E. Ryherd – eryherd@unl.edu
Durham School of Architectural Engineering and Construction
University of Nebraska – Lincoln
203C Peter Kiewit Institute
Omaha, NE 68182-0176

Lauren Ronsse – lronsse@colum.edu
Columbia College Chicago
33 E. Congress Parkway, Suite 601
Chicago, IL 60605

Popular version of paper 3pID2, “The state of the art in worship space acoustics”
Presented Wednesday afternoon, May 25, 2016, 1:55 in Salon D
171st ASA Meeting, Salt Lake City

From the clanging of bells to the whisper of burning incense, sound is essential to the worship experience. It follows that the acoustic environment is paramount in the sacred place – the worship space – and thoughtful design is required to achieve a worship experience full of awe and wonder. The first intentional sacred spaces were constructed over 11,000 years ago [1] and, although architectural acoustics design practices have changed immeasurably since then, the primary use of these spaces remains essentially unchanged: to provide a gathering space for communal worship.

To meet this need, the four key acoustical goals that modern worship space designers must consider are to optimize reverberation time, eliminate acoustical defects, minimize ambient noise, and maximize dynamic range. These four goals are imperative in virtually all types of worship spaces around the world, despite vast dif­ferences in religious practices and beliefs. In the recent publication, Worship Space Acous­tics: 3 Decades of Design [2], the application of these goals is seen in 67 churches, synagogues, mosques, and other worship spaces designed in the past thirty years. Each space and each religion has its own id­iosyncratic acoustic challenges, from a visually translucent but acoustically transparent partition required to separate men and women in an orthodox syna­gogue in Brookline, MA (Figure 1) to the attenuation of a focused acoustic reflection from the dome of a mosque in Atlanta, GA (Figure 2). One space featured in the book, Temple Israel (Figure 3), shows the connectedness of acoustical design in worship spaces. It is part of a special project, the Tri-Faith Initiative, a 14-acre complex in Omaha, NE uniting three Abrahamic faith groups, Temple Israel, Countryside Community Church (United Church of Christ), and The American Muslim Institute. As each of these three worship spaces is constructed on the site, they all must have the four key acoustical goals considered.

In the past three decades, worship spaces have seen an increased need for multi-functionality, often hosting religious services with varying acoustical needs. For example, the Star Performing Arts Centre (Figure 4) in Singapore serves as the home of the New Creation Church, seats 5000 people, and supports programing ranging from traditional worship services to pop music concerts to televised national events. Some spaces must even serve more than one religion, such as the Sacred Space (Figure 5), a multi-faith house of worship constructed in the shell of an old Boston chapel that caught fire in the mid-90s, now used for meditation, private worship, and small gatherings. These varying usage requirements require careful consideration of the acoustic design, often relying on variable acoustics such as retractable sound absorption and the use of sophisticated electroacoustics systems.

Although the use of each space may vary, the most important acoustic goal remains to optimize the reverberation time. This is the time necessary for sound in a space to decay to one-millionth of its original intensity. Essentially, it describes how the sound energy decays, perceived as the fading away of sound over time. Typically, reverberation time decreases as more sound absorption is added, and increases as the size of the space increases. Figure 6 shows the mean reverberation times (500 Hz) for the various seating capacities of the 67 worship spaces. Seating capacity is generally directly proportional to size of the space, and the reverberation times here show the general trend of increasing with increasing size up to about 2000 seats. For 2000 seats and beyond, the data show a marked decrease in reverberation time. For these larger spaces, there tends to be a higher proportion of sound absorbing material used in the design, typically to allow for the use of electroacoustics systems that require a large number of loudspeakers. Spaces that rely heavily on electroacoustics to achieve the desired sonic environment require non-reflective surfaces and lower reverberation times for the microphone-loudspeaker systems to work properly.

Regardless of reverberation time, the goal remains the same, to create a gathering space for worship where the sound is sacred.

  1. K. Schmidt, “Göbekli Tepe, Southeastern Turkey: A Preliminary Report on the 1995-1999 Excavations,” Paléorient, 26(1), 45-54, 2000.
  2. D. T. Bradley, E. E. Ryherd, and L. Ronsse (Eds.), Worship Spaces Acoustics: 3 Decades of Design, (New York, NY, Springer, 2016).


view from ezrat nashim

Figure 1: Temple Young Israel, a 550-seat orthodox synagogue in Brookline, MA designed by Gund Partnership and Cavanaugh Tocci Associates, Inc. (Photo credit: Christopher A. Storch)

ceiling dome artwork

Figure 2: Al Farooq Masjid of Atlanta (interior view of main dome), a 1500-seat Islamic mosque designed by Lee Sound Design, Inc. and Design Arts Studio and EDT Constructors, Inc. (Photo credit: Wayne Lee)


Figure 3: Temple Israel, a 900-seat reform synagogue in Omaha, NE designed by Acentech Incorporated and Finegold Alexander + Associates. (Photo credit: Finegold Alexander + Associates)

view from the stage

Figure 4: The Star Performing Arts Centre, a 5000-seat multi-use space in Singapore designed by Arup (completed as Artec) and Andrew Bromberg of Aedas.

interior view

Figure 5: The Sacred Space, 150-seat multifaith house of worship in Boston, MA designed by Acentech Incorporated and Office dA.


Figure 6: Mean reverberation times at 500 Hz octave band center frequency for 67 worship spaces of varying seating capacity.

5aMU1 – Understanding timbral effects of multi-resonator/generator systems of wind instruments in the context of western and non-western music – Jonas Braasch

Popular version of poster 5aMU1
Presented Friday morning, May 22, 2015, 8:35 AM – 8:55 AM, Kings 4
169th ASA Meeting, Pittsburgh

In this paper the relationship between musical instruments and the rooms they are performed in was investigated. A musical instrument is typically characterized as a system that consists of a tone generator combined with a resonator. A saxophone for example has a reed as a tone generator and a comical shaped resonator that can be effectively changed in length with keys to produce different musical notes. Often neglected is the fact that there is a second resonator for all wind instruments coupled to the tone generator – the vocal cavity. We use our vocal cavity everyday when we speak to form characteristic formants, local enhancements in frequency to shape vowels. This is achieved by varying the diameter of the vocal tract at specific local positions along its axis. In contrast to the resonator of a wind instrument, the vocal tract is fixed its length by the dimensions between the vocal chords and the lips. Consequently, the vocal tract cannot be used to change the fundamental frequency over a larger melodic range. For out voice, the change in frequency is controlled via the tension of the vocal chords. The musical instrument’s instrument resonator however is not an adequate device to control the timbre (harmonic spectrum) of an instrument because it can only be varied in length but not in width. Therefore, the players adjustment of the vocal tract is necessary to control the timbre if the instrument. While some instruments posses additional mechanisms to control timbre, e.g., via the embouchure to control the tone generator directly using the lip muscles, for others like the recorder changes in the wind supply provided by the lungs and the changes of the vocal tract. The role of the vocal tract has not been addressed systematically in literature and learning guides for two obvious reasons. Firstly, there is no known systematic approach of how to quantify internal body movements to shape the vocal tract. Each performer has to figure out the best vocal tract configurations in an intuitive manner. For the resonator system, the changes are described through the musical notes, and in cases where multiple ways exist to produce the same note, additional signs exist to demonstrate how to finger this note (e.g., by providing a specific key combination). Secondly, in western classic music culture the vocal tract adjustments predominantly have a correctional function to balance out the harmonic spectrum to make the instrument sound as even as possible across the register.


PVC-Didgeridoo adapter for soprano saxophone

In non-western cultures, the role of the oral cavity can be much more important to convey musical meaning. The didgeridoo, for example, has a fixed resonator with no keyholes and consequently it can only produce a single pitched drone. The musical parameter space is then defined by modulating the overtone spectrum above the tone by changing the vocal tract dimensions and creating vocal sounds on top of the buzzing lips on the didgeridoo edge. Mouthpieces of Western brass instruments have a cup behind the rim with a very narrow opening to the resonator, the throat. The didgeridoo does not have a cup, and the rim is the edge of the resonator with a ring of bee wax. While the narrow throat of western mouthpiece mutes additional sounds produced with the voice, didgeridoos are very open from end to end and carry the voice much better.

The room, a musical instrument is performed in acts as a third resonator, which also affect the timbre of the instrument. In our case, the room was simulated using a computer model with early reflections and late reverberation.

Braasch 1
Tone generators for soprano saxophone from left to right: Chinese Bawu, soprano saxophone, Bassoon reed, cornetto.

In general, it is difficult to assess the effect of a mouthpiece and resonator individually, because both vary across instruments. The trumpet for example has a narrow cylindrical bore with a brass mouthpiece, the saxophone has a wide conical bore with reed-based mouthpiece. To mitigate this effect, several tone generators were adapted for a soprano saxophone, including a brass mouthpiece from a cornetto, a bassoon mouthpiece and a didgeridoo adapter made from a 140 cm folded PCV pipe that can be attached to the saxophone as well. It turns out that the exchange of tone generators change the timbre of the saxophone significantly. The cornetto mouthpiece gives the instrument a much mellower tone. Similar to the baroque cornetto, the instruments sounds better in a bright room with lot of high frequencies, while the saxophone is at home at a 19th-century concert hall with a steeper roll off at high frequencies.

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