Case study for voice amplification in a highly absorptive conference room using a negative absorption tuning by the Yamaha Active Field Control system
Takayuki Watanabe · The Journal of the Acoustical Society of America · 2006
The Yamaha Active Field Control (AFC) enhances and varies acoustical conditions from the room acoustics using the acoustical feedback in a system, which is properly tuned to the installed room acoustics. The system is primarily used to improve auditory impressions of reverberance, loudness by enhancement of reverberation in time, and energy in a music venue. Here, a negative absorption tuning is demonstrated as beneficial to the presentation room for a simple spoken speech used with a relatively excessive absorption at a middle-sized multiuse conference room. The space occupies 1100 ft2 with a ceiling height of 9 ft. It is designed for demonstration of sound equipment as well as lecture without audio equipment. Since the acoustics in the room are highly absorptive (average absorption coefficient, 0.3), considering a primary use for product demonstration, it causes a flutter echo between longitudinal walls due to less sound energy in a late field. We demonstrate here a system adjustment of the AFC system emphasizing voice amplification as well as an acoustical solution to a defect of a fluttering echo here. Acoustical descriptors such as RT, echo diagram, and SPL are discussed for a tuned room acoustics with the AFC system.