Christopher Jaffe

Boardroom sound reinforcement system

A sound reinforcement system for a meeting room provides improved effective communication between several individuals located at a distance from one another within a room, as around a large conference table in a corporate boardroom, by positioning a pair of speakers driven out of phase with one another at each individual location and positioning a microphone within the acoustical cancellation zone of the corresponding speaker pair. Acoustical gain is further improved by feeding the signal from each microphone to all speaker pairs except the one to which it corresponds and/or by making the level of a signal arising from a speaker pair proportional to its distance from the microphone that picked up that signal.

Sound and vibration control for the Tokyo International Forum

The acousticians for the Tokyo International Forum were faced with a number of very severe noise and vibration problems related to the siting of the complex in the center of downtown Tokyo, the placement of the performance halls next to one another, and the location of a portion of the mechanical equipment on the roof. In addition, subway lines ran parallel to three of the boundaries of the structure, another line ran under the building, and the main tracks of Japan Rail ran above ground alongside the major atrium. This paper will discuss the noise criteria set for the performance rooms and other noise sensitive spaces, the noise and vibration measurements taken to determine the severity of the train‐related conditions, predictions of other noise and vibration sources, and the solutions developed by the design team to meet the criteria required by the program. Among the solutions are a secant wall surrounding the foundation, box in box construction for the four performance halls, blocking mass installatio...

Graduate Program in Architectural Acoustics at the School of Architecture, Rensselaer Polytechnic Institute.

Established in 1998, the Graduate Program in Architectural Acoustics at Rensselaer’s School of Architecture has grown rapidly. The program offers both masters and doctoral degrees in a stimulating academic and research atmosphere. Applicants come from a variety of disciplines, including those with bachelor‐level degrees (B. Arch., B.S., or B.A.) in Architecture, Music, Engineering, Audio/Recording Engineering, Physics, Mathematics, Computer Science, Acoustics, Electronic Media, Theater Technology, or related fields. The core curricula include Architectural Acoustics, Sonics Research Laboratory, Engineering Acoustics, Applied Psychoacoustics, and Communication Acoustics. Since its inception, the program has awarded more than 65 masters degrees and four doctorates. A majority of the program’s graduates have developed careers in acoustics consulting. The emphasis of the program’s curricula, its preparation for serving architectural acoustics consultants and professionals, and the research strategy at both th...

My colleague and competitor: Russell Johnson.

This presentation documents the relationship between two architectural acoustic consultants that were active throughout the second half of the 20th century and into the 21st century. It illustrates the fact that practioners in a competive setting, devoted to the search for truth, can work together to arrive at solutions that enable a discipline to move forward.

The application of acoustically coupled spaces in concert hall design

At mid‐twentieth century, a hall having a reverberation decay curve with a late arriving extended second slope was considered an acoustical failure. It was assumed that that the level of the extended reverberation in the hall would interfere with the ongoing running music of the ensemble and reduce orchestral clarity, definition and transparency. To my knowledge, only two practitioners pioneered the utilization of physical acoustic coupling in concert shell and concert hall design during those early years. One was Russell Johnson, when he was with Bolt Beranek and Newman and later with his own firm Artec. The other was me with both my firms Stagecraft Corporation and Jaffe Acoustics. This paper discusses how the need to improve the concert hall environment of American multi‐use theatres led to the application of coupling techniques in these halls and how both Mr. Johnson and I later applied physical acoustic coupling in single room concert spaces.

Qualitative Standard for Symphonic Concert Environment

All acousticians strive to obtain a symphonic concert environment that will be well received by musicians, professional music critics and the general public. Currently, this environment corresponds to the reflective energy measurements found in what might be designated as the rectangular European or American Concert Hall of the late nineteenth century, such as the Grosser Musikvereinssaal in Vienna and Symphony Hall in Boston Massachusetts. It is well known that these measurements can be correlated to subjective musical judgments and that halls incorporating these measurements have been universally designated as having excellent environments for symphonic concerts. But how did these specific reflections become an acoustical standard. This paper presents a theory of how the rectangular European and American style concert hall became an acoustical standard at the beginning of the twentieth century and poses the question as to whether this standard is still applicable in the twenty first century?

The value of utilizing binaural dummy head recordings in evaluating physical acoustic changes in concert halls

In some instances, after a concert hall is built there may be a need to modify the physical environment of the space through the application of diffusion or absorptive surfaces, the addition of reflector systems or the repositioning of the orchestra in the space. Prior to moving forward with suggested changes to the physical environment, it has been customary to conduct evaluation rehearsals with physical mock‐ups installed to confirm the acousticians recommendations. Questionnaires are given to the musicians, the conductor and the administration staff to document the effect of the changes, and physical measurements are taken before and after the installation of the mock‐ups. The questionnaires can be difficult to correlate and the differences in data resulting from the physical measurements may be too small to properly evaluate. More recently, Jaffe Holden Acoustics has added dummy head recordings to the mix. These recordings are extremely representative of what a human hears and one can place these devi...

There’s nothing Majestic about burlesque

Turn‐of‐the‐century vaudeville and movie palaces initially seem to lend themselves to use as concert halls or multipurpose theatres. Basic features, including existing structure, appropriate location, and desirable seat count, already exist. But, upon further investigation, these palaces present both acoustical and theatrical limitations. Specifically, shallow stage depth, undersized stage wings, small orchestra pit, deep balcony overhangs, and low ceiling height in stage house and/or audience chamber are common deficiencies which must be addressed in successful conversions. Despite these challenges, converting an existing building is often a viable option for many communities. This paper will investigate several representative palaces which were modified to accommodate modern symphonic and theatrical productions between 1959 and the present.

The first vineyard concert hall in North America

The first vineyard or surround concert hall designed and built in the Western Hemisphere is the Sala Nezahualcoyotl in Mexico City. The Hall was completed in 1976 and is part of the Cultural Center at the Universidad Nacional Autonoma de Mexico. The hall was named after a Toltec poet, architect, and musician who lived in the 15th century and was the Renaissance man of his day. In order to provide the familiar traditional sound of the rectangular (shoebox) European Hall, the acoustic designers set the criteria for reverberation times through the frequency spectrum and the Initial Time Delay Gap at every seat in the house to match the measurements taken at the Grosser Musik vereinssaal in Vienna and Boston Symphony Hall. In this paper we discuss the techniques used to create the traditional sound in a vineyard hall and the reaction of musicians and audiences to the completed facility. The Sala was the model for Suntory Hall in Japan which in turn spawned a number of vineyard halls in Japan. Most recently, t...

Concert hall acoustics at Bass Hall

Traditionally, multi‐purpose halls are believed to have less than adequate symphonic acoustic listening characteristics compared to one room concert halls such as Boston Symphony Hall. Over the last two years, students and faculty of the Sonics Program at the Rensselaer Polytechnic Institute conducted a series of measurements at the multi‐purpose Bass Performance Hall in Forth Worth, Texas. In this investigation, Bass Hall is shown to have excellent concert hall metrics when configured for that purpose. Measurements of reverberation time, early decay time, clarity (C80), and center time (Ts) were taken according to the ISO 3382 standard. This data was compared to data from the great one‐room concert halls. This comparison demonstrates that Bass Hall can function as an equally excellent concert hall, in spite of being a multi‐purpose hall. [Research supported by the Bass Foundation.]