KALAMAZOO, MI – Stage Lighting and Sound, Inc. recently installed a new custom-designed Yamaha Active Field Control (AFC) reverberation enhancement system at Western Michigan University's Miller Auditorium to enhance the acoustics. The venue, built in 1968, is used for touring Broadway productions, concerts by major touring musical artists, ballet, opera and dance, and is the home of the Kalamazoo Symphony Orchestra.
Prior to the new system, some of the problems reported by staff and visiting artists were that the existing hall was a dry acoustical environment. In addition, performers were having difficulty on-stage hearing properly, which was affecting performance due to low energy return from the house. Sound dramatically fell off in the under balcony area, and enhancement of the loudness in the space was needed to provide a more uniform experience at Miller Auditorium.
In late summer 2005, Stage Lighting and Sound, Kalamazoo, Mich., received a telephone call from David Clemens, head sound technician at Western Michigan University’s Miller Auditorium inquiring about the Yamaha AFC system. That telephone call led Elaine Williams, director of Miller Auditorium, Dr. Robert Spradling, director of Instrumental Music at Western Michigan University, David Clemens and Bob Hartman of Stage Lighting and Sound, Inc. on a two-year journey.
Stage Lighting and Sound was asked to do a preliminary cost estimate and Bob Hartman was given the drawings of Miller Auditorium including the stage house and the orchestra shell. The second step in the process occurred when Stage Lighting and Sound sent the drawings to Yamaha’s AFC designer Masahiro (Hiro) Ikeda. Within two weeks, drawings of the speaker and microphone placement, along with an equipment list were sent to Stage Lighting and Sound, Inc. from Yamaha Corporation Japan. In June 2006, acoustic engineers from Yamaha visited WMU and began to analyze and design the components for reverberation enhancement at Miller Auditorium.
Yamaha Active Field Control (AFC) system is a reverberation enhancement system that preserves the natural acoustics in a room. Yamaha DSP technology realizes this system with only a small set of core devices and is used to improve the architectural acoustic characteristics of a room or optimize reverberation time performance in the room depending on the type of event. AFC controls acoustical conditions based on the existing room condition by utilizing an acoustical feedback system making it unique to other popular techniques that are based on the use of digital reverbs to simulate room characteristics. The system enables the auditorium to hold classical concerts in a very large hall without the need of a sound reinforcement system.
Final installation at Miller Auditorium took place in July 2007, and for several weeks afterward, Yamaha Commercial Audio Systems had engineers on campus fine-tuning the system to Miller Auditorium's performance space, ensuring the most precise acoustic results possible.
Miller Auditorium has two AFC Systems. One is a reverberation system for enhancement in the seating area; the other is an energy exchange system for improvement of the uniformity between the stage and seating area. The reverberation system consists of eight microphones and 62 speakers. Forty-two speakers serve in the main seating area and 20 speakers serve in the under balcony area. Three processors are used to manage the input mixing, sound processing, and output controls. Eight microphones are located at the proscenium arch to collect the sound from the stage at around the critical distance where the direct sound energy equals that of the diffused sound.
The energy exchange system consists of an additional four microphones located further into the house. These are used with eight speakers installed over the stage area to provide a more uniform response between the house sound and the stage. Two processors are used to manage the input mixing, the sound processing, and the output controls. The four microphones are located at the ceiling in the seating area to collect the diffused sound in this part of the room. Eight speakers are also located at the stage shell ceiling to enhance the reverberance on stage.
System components include 12 Audio Technica ES945 mics, two HA & AD Yamaha AD8HRs, five Main Unit Yamaha AFC1s, two Yamaha MY8AE-CA interface cards, nine Yamaha MY8DA96-CA interface cards, three Cascade Cables, two AES D24 Cables, nine Breakout DA96 Cables, 18 4-channel Yamaha XM4080 power amps, 42
Yamaha S8AFC loudspeakers, and 28 Yamaha S8AFC-D loudspeaker drivers.
“My first reaction was that everyone on stage could hear each other better and as a result did not have to work as hard to produce the desired sound,” states Dr. Spradling. “We had always been challenged by the need to project additional bass sound in order to achieve the balance that was necessary in the music. In our system test on stage, we found that the bass instruments could relax as they were well balanced without having to over project. In addition, we discovered a new clarity in terms of the audience hearing everything happening on stage. Inner voices in the ensemble as well as soloists performing from various points on the stage were clearly heard without any sense of artificial amplification. What you hear on stage is finally what the audience hears in the hall… good or bad.”
For information, please visit www.yamahaca.com.
