AFC Yamaha Active Field Control (AFC) Immersive Audio System
What is AFC Enhance?
Not suitable for musical performance
Ideal for musical performance
AFC Enhance controls the acoustic environment via multiple microphones and loudspeakers strategically located throughout the space. This type of system generally employs one of the two following methods.
- “Regenerative approach” uses acoustic feedback, reproducing the sound picked up by the microphones via the loudspeakers and then picking up that sound affected by the room’s acoustics once more, thereby creating an acoustic “loop” that amplifies the room’s acoustic energy.
- “In-line approach” uses convolution signal processing to add a variety of synthesized reflected sound data (measured impulse responses) to the sound picked up via the microphones, to create the desired sonic environment.
AFC Enhance is a hybrid system that employs both of these methods. Through detailed control of reverberation and early reflections that have a profound influence on auditory impression, the sound propagating throughout the room can be adjusted as required while retaining the natural acoustic properties of the room’s structure.
|AFC Enhance Engines*||2, 4, 6|
|Inputs||32 microphones, 24 AUX|
|Sample Rate||48kHz, 96kHz|
|Control devices||ProVisionaire Control, ProVisionaire Touch, MCP1, Third party control|
|System I/O||Dante Only|
|H||7" ( 4U)|
|Net Weight||48.5 Lbs|
EMR: Switching Function for Stability
AFC Enhance employs a feedback loop for acoustic control. For optimum effect it is necessary to feed back as much energy as possible, but the more energy is fed back the higher the risk of uncontrolled feedback becomes. To keep the feedback loop under control at all times, the AFC Enhance system uses EMR (Electronic Microphone Rotator) technology to apply time variation, evenly distributing the loop’s frequency characteristics for dramatically increased howling resistance. EMR: System output is time-shifted to evenly distribute the feedback loop’s frequency characteristics. At any point in time the inputs are aligned with one of the outputs while the other outputs remain independent. The move from channel to channel is accomplished smoothly along with amplitude modulation (the allocation ratio for each channel remains constant).
*EMR is a patented Yamaha technology.
The latest AFC Enhance system features much higher-density FIR processing power than previous versions so that extremely natural-sounding detailed reflection sound can be achieved even in dead spaces that have very little natural reverberation: Up to 10.666 sec at 48kHz / 5.333 sec at 96kHz.
AFC Enhance Patent List
|Pat.No.||Title||Date of Pat.||Contents|
|5,025,472||Reverberation imparting device||1991||Basic idea Feedback/FIR|
|5,131,051||Method and apparatus for controlling the sound field in auditoriums||1992||Energy exchange|
|5,642,425||Sound field control device||1997||EMR|
|6,072,879||Sound field control unit and sound field controll device||2000||YUME-HIBIKI including EMR & Fluc-FIR|
|6,157,724||Apparatus having loudspeakers concurrently producing music sound and ref||2000||Music instrument including EMR & Fluc-FIR|
|7,474,753||Sound field control apparatus, signal processing apparatus, sound field control program, and signal processing program||2009||Hardware Configuration|