"Active Field Control (AFC) is a reverberation enhancement system that employs electro-acoustic technologies enabling "natural changes" to major auditory impressions, such as reverberance, loudness and spaciousness. The system can be used to realize optimum acoustic conditions for various purposes of sound fields such as concert hall, church, education facility, rehearsal room, arena, etc. AFC is a stable system against the coloration problem caused by a feedback loop, since Time Varying Control (TVC) including EMR and fluc-FIR is implemented in the system." Copyright (C)2009 Yamaha Corporation. All rights reserved.