Acoustic enhancement
Encyclopedia
Acoustic enhancement is a subtle type of sound reinforcement system
used to augment direct, reflected, or reverberant sound. While sound reinforcement systems are usually used to increase the sound level of the sound source (like a person speaking into a microphone, or musical instruments in a pop ensemble), acoustic enhancement systems are typically used to increase the acoustic energy in the venue. These systems are often associated with acoustic sound sources like a chamber orchestra, symphony orchestra, or opera
, but have also found acceptance in a variety of applications and venues that include rehearsal rooms, recording facilities conference rooms, sound stages, sports arenas, and outdoor venues.
s, amplifiers, and loudspeaker
s interconnected with some form of processing. The number, type, and placement of microphones and loudspeakers varies according to both the application, as well as the physics limitations that are imposed by the inherent operating principles associated with each manufacturer's equipment. In most instances, however, these systems employ at least one array of loudspeakers that are distributed throughout the venue.
As concertgoers have become aware of the use of these systems, debates have arisen, because "...purists maintain that the natural acoustic sound of [Classical] voices [or] instruments in a given hall should not be altered." When employed properly, however, acoustic enhancement can improve listening quality in ways that would be impossible for architectural treatments to accomplish, and deliver sound quality that the concertgoer desires to experience.
At the Vienna Festival
in May, 1995, a LARES
system was used outdoors to augment the Vienna Philharmonic's performance of Beethoven's Symphony No. 9 conducted by Zubin Mehta. "This was the first time on this location with classical music that we were not criticised for spoiling the music by amplifying it. "Alfred Toegel, Sound Department, Vienna Festival. Commenting on a performance by the Grant Park Orchestra at the Jay Pritzker Pavillion at Millennium Park Chicago IL, Senior V.P. of WFMT Radio Steve Robinson stated "I have never in my life heard sound projected so faithfully and beautifully over such a great distance; it was an ethereal experience"
Kai Harada's article Opera's Dirty Little Secret
states that opera houses have begun using electronic acoustic enhancement systems "...to compensate for flaws in a venue's acoustical architecture." Despite the uproar that has arisen amongst operagoers, Harada points out that none of the major opera houses using acoustic enhancement systems "...use traditional, Broadway
-style sound reinforcement, in which most if not all singers are equipped with radio [headset] microphones
mixed to a series of unsightly loudspeakers scattered throughout the theatre."
Instead, most opera houses use the sound reinforcement system for subtle boosting of offstage voices, onstage dialogue, and sound effects (e.g., church bells in Tosca
or thunder in Wagnerian operas). Acoustic Enhancement systems are most often employed in traditional opera houses to improve the sound of the orchestra, and have little if any effect on the sound of the voices. In a review of the State Opera of South Australia's performance of Wagners' Ring cycle at the Adelaide Festival Center Theatre, Michael Kennedy
of The Sunday Telegraph, London, wrote: “The balance between the orchestra and the voices has been ideal.” The live recording of "Wagner: Die Walküre", the world's first 6 channel SACD "blitzed the 2005 Helpmann Awards, winning ten of its eleven nominations and earning critical accolades." - and the recording of "Wagner: Götterdämmerung" was nominated for a 2008 Grammy award. "
In-line systems with electronic reverberators:
Acoustic enhancement systems include LARES (Lexicon Acoustic Reinforcement and Enhancement System) and SIAP, the System for Improved Acoustic Performance. These systems use microphones, computer processing "with delay, phase, and frequency-response changes," and then send the signal "... to a large number of loudspeakers placed in extremities of the performance venue." The Deutsche Staatsoper in Berlin and the Hummingbird Centre in Toronto use a LARES system. The Ahmanson Theatre
in Los Angeles, the Royal National Theatre
in London, and the Vivian Beaumont Theatre
in New York City use the SIAP system.
Feedback systems with electronic reverberators:
Another acoustic enhancement system, VRAS
(Variable Room Acoustics System) uses "...different algorithms based on microphones placed around the room."
Feedback systems without electronic reverberators:
CARMEN developed by CSTB comprises a number of electro acoustic active cells (approximately from 16 to 40), each of them being composed of a microphone, an electronic filtering unit, a power amplifier and a loudspeaker. Placed around the walls and ceiling of the auditorium, the cells form virtual walls depending on the architecture and the acoustic problem to solve. They only communicate between each other by the acoustic way.
Sound reinforcement system
A sound reinforcement system is the combination of microphones, signal processors, amplifiers, and loudspeakers that makes live or pre-recorded sounds louder and may also distribute those sounds to a larger or more distant audience...
used to augment direct, reflected, or reverberant sound. While sound reinforcement systems are usually used to increase the sound level of the sound source (like a person speaking into a microphone, or musical instruments in a pop ensemble), acoustic enhancement systems are typically used to increase the acoustic energy in the venue. These systems are often associated with acoustic sound sources like a chamber orchestra, symphony orchestra, or opera
Opera
Opera is an art form in which singers and musicians perform a dramatic work combining text and musical score, usually in a theatrical setting. Opera incorporates many of the elements of spoken theatre, such as acting, scenery, and costumes and sometimes includes dance...
, but have also found acceptance in a variety of applications and venues that include rehearsal rooms, recording facilities conference rooms, sound stages, sports arenas, and outdoor venues.
Design and application
Acoustic enhancement systems use microphoneMicrophone
A microphone is an acoustic-to-electric transducer or sensor that converts sound into an electrical signal. In 1877, Emile Berliner invented the first microphone used as a telephone voice transmitter...
s, amplifiers, and loudspeaker
Loudspeaker
A loudspeaker is an electroacoustic transducer that produces sound in response to an electrical audio signal input. Non-electrical loudspeakers were developed as accessories to telephone systems, but electronic amplification by vacuum tube made loudspeakers more generally useful...
s interconnected with some form of processing. The number, type, and placement of microphones and loudspeakers varies according to both the application, as well as the physics limitations that are imposed by the inherent operating principles associated with each manufacturer's equipment. In most instances, however, these systems employ at least one array of loudspeakers that are distributed throughout the venue.
As concertgoers have become aware of the use of these systems, debates have arisen, because "...purists maintain that the natural acoustic sound of [Classical] voices [or] instruments in a given hall should not be altered." When employed properly, however, acoustic enhancement can improve listening quality in ways that would be impossible for architectural treatments to accomplish, and deliver sound quality that the concertgoer desires to experience.
At the Vienna Festival
Vienna Festival
The Wiener Festwochen is a cultural festival in Vienna that takes place every year for five or six weeks in May and June.The Wiener Festwochen was established in 1951, when Vienna was still occupied by the four Allies...
in May, 1995, a LARES
LARES
LARES is an electronic sound enhancement system that uses microprocessors to control multiple loudspeakers and microphones placed around a performance space for the purpose of providing active acoustic treatment. LARES was invented in Massachusetts in 1988, by engineers working at Lexicon,...
system was used outdoors to augment the Vienna Philharmonic's performance of Beethoven's Symphony No. 9 conducted by Zubin Mehta. "This was the first time on this location with classical music that we were not criticised for spoiling the music by amplifying it. "Alfred Toegel, Sound Department, Vienna Festival. Commenting on a performance by the Grant Park Orchestra at the Jay Pritzker Pavillion at Millennium Park Chicago IL, Senior V.P. of WFMT Radio Steve Robinson stated "I have never in my life heard sound projected so faithfully and beautifully over such a great distance; it was an ethereal experience"
Kai Harada's article Opera's Dirty Little Secret
states that opera houses have begun using electronic acoustic enhancement systems "...to compensate for flaws in a venue's acoustical architecture." Despite the uproar that has arisen amongst operagoers, Harada points out that none of the major opera houses using acoustic enhancement systems "...use traditional, Broadway
Broadway theatre
Broadway theatre, commonly called simply Broadway, refers to theatrical performances presented in one of the 40 professional theatres with 500 or more seats located in the Theatre District centered along Broadway, and in Lincoln Center, in Manhattan in New York City...
-style sound reinforcement, in which most if not all singers are equipped with radio [headset] microphones
Headset (telephone/computer)
A headset is headphones combined with a microphone, or one headphone with a microphone. Headsets provide the equivalent functionality of a telephone handset with hands-free operation. Headsets typically have only one speaker like a telephone, but also come with speakers for both ears...
mixed to a series of unsightly loudspeakers scattered throughout the theatre."
Instead, most opera houses use the sound reinforcement system for subtle boosting of offstage voices, onstage dialogue, and sound effects (e.g., church bells in Tosca
Tosca
Tosca is an opera in three acts by Giacomo Puccini to an Italian libretto by Luigi Illica and Giuseppe Giacosa. It premiered at the Teatro Costanzi in Rome on 14 January 1900...
or thunder in Wagnerian operas). Acoustic Enhancement systems are most often employed in traditional opera houses to improve the sound of the orchestra, and have little if any effect on the sound of the voices. In a review of the State Opera of South Australia's performance of Wagners' Ring cycle at the Adelaide Festival Center Theatre, Michael Kennedy
Michael Kennedy (music critic)
Dr. George Michael Sinclair Kennedy CBE is an English biographer, journalist and writer on classical music. He joined the Daily Telegraph at the age of 15 in 1941, and began writing music criticism for it in 1948...
of The Sunday Telegraph, London, wrote: “The balance between the orchestra and the voices has been ideal.” The live recording of "Wagner: Die Walküre", the world's first 6 channel SACD "blitzed the 2005 Helpmann Awards, winning ten of its eleven nominations and earning critical accolades." - and the recording of "Wagner: Götterdämmerung" was nominated for a 2008 Grammy award. "
Types
There exist different types of acoustic enhancement systems: In-line and Feedback systems with or without electronic reverberators.In-line systems with electronic reverberators:
Acoustic enhancement systems include LARES (Lexicon Acoustic Reinforcement and Enhancement System) and SIAP, the System for Improved Acoustic Performance. These systems use microphones, computer processing "with delay, phase, and frequency-response changes," and then send the signal "... to a large number of loudspeakers placed in extremities of the performance venue." The Deutsche Staatsoper in Berlin and the Hummingbird Centre in Toronto use a LARES system. The Ahmanson Theatre
Ahmanson Theatre
The Ahmanson Theatre is one of the four main venues that comprise the Los Angeles Music Center.Through the generosity of philanthropist Robert H. Ahmanson, construction began on March 9, 1962. The theatre opened on April 12, 1967 with a production of More Stately Mansions starring Ingrid Bergman,...
in Los Angeles, the Royal National Theatre
Royal National Theatre
The Royal National Theatre in London is one of the United Kingdom's two most prominent publicly funded theatre companies, alongside the Royal Shakespeare Company...
in London, and the Vivian Beaumont Theatre
Vivian Beaumont Theatre
The Vivian Beaumont Theater is a theatre located in the Lincoln Center complex at 150 West 65th Street on the Upper West Side of Manhattan. The structure was designed by Finnish American architect Eero Saarinen, and Jo Mielziner was responsible for the design of the stage and interior.The Vivian...
in New York City use the SIAP system.
Feedback systems with electronic reverberators:
Another acoustic enhancement system, VRAS
VRAS
The Variable Room Acoustics System is an acoustic enhancement system for controlling room acoustics electronically. Such systems are increasingly being used to provide variable acoustics for multipurpose venues....
(Variable Room Acoustics System) uses "...different algorithms based on microphones placed around the room."
Feedback systems without electronic reverberators:
CARMEN developed by CSTB comprises a number of electro acoustic active cells (approximately from 16 to 40), each of them being composed of a microphone, an electronic filtering unit, a power amplifier and a loudspeaker. Placed around the walls and ceiling of the auditorium, the cells form virtual walls depending on the architecture and the acoustic problem to solve. They only communicate between each other by the acoustic way.