AFC Enhance Reverberation Control

What is AFC Enhance?

AFC Enhance controls the reverberation of a space while making use of the natural acoustic properties of the existing structure. Unlike approaches that add artificial reverb to the source sound to create a different impression, AFC Enhance employs technology developed over many years to control sound propagation within the actual space so that reverberation and volume can be altered while the natural sounds of musical instruments and voices are maintained. Relatively dead acoustic spaces such as event spaces, assembly halls, and banquet rooms that don’t have much reverberation are fine for speech, but if a performance of classical music is held in such spaces the sound lacks depth, making it difficult for the performers and audience to enjoy the sound. An AFC Enhance system can create an ideal sonic environment without the need for structural renovations.

Musical performance

Optimize acoustic spaces for any scene or situation

Optimum reverberation can vary greatly depending on the application. AFC Enhance can create ideal reverberation for an extremely wide range of content and situations without the need for soundboards or other physical treatments that require time and resources to set up. Reverberation can even be changed on the fly, providing optimum ambience for different scenes in a theatrical production, for example. The ability to quickly and easily alter the sonic atmosphere of a space makes it possible to deliver the best possible experience to the audience.

Experiential installation

Create unique atmospheres for experiential installations

- Sound is the critical component to create the experience for sound installation such as museum exhibits, theme park, etc.

- AFC Enhance will create unexpected experience by changing the space reverberation drastically which the audience can never experience in their daily life.

Sports event

Enhanced excitement for sports events

AFC Enhance can also be used to enhance the atmosphere at sports events, making the event even more thrilling for both players and spectators. The sounds of voices, applause, and the environment in general are captured, processed, and redistributed throughout the venue to maximize spectator excitement while simultaneously spurring the players on to greater achievement.

See an example here

Rehearsal room

More productive rehearsals

Rehearsals will be more productive and give the artists greater confidence if done in an environment that accurately matches the acoustic characteristics of the actual performance space. Rehearsal rooms are typically less reverberant than the venue, which can make it difficult for artists to prepare properly. With AFC Enhance, a quick press of a button is all it takes to match the acoustic environment of the rehearsal room to the final performance space.

Music and Movement - Active Field Control Brings Music and Dance Together -

Let's Dance With The Orchestra! was a unique collaboration of live dance and orchestral music, staged at the Kani City Cultural and Creative Center, in Japan’s Gifu prefecture. Yamaha’s AFC Enhance and AFC Image immersive audio solutions ensured that the audience, dancers and musicians all enjoyed the best possible sound.

Yamaha Active Field Control Makes World First Classical Performance Possible

In October 2021, a world first saw the Shimizu Cultural Centre Marinat in Shizuoka City, Japan host a unique production titled The Marinart Forest, directed and conducted by Maestra Tomomi Nishimoto and performed by the IlluminArt Philharmonic Orchestra and Choir.

Yamaha and NEXO AFC System is the Sound of Success for Award-Winning Qatar University Installation

Today’s sound, lighting and control technology can offer customers flexibility in multipurpose spaces that, in the past, could only be dreamed about. A recent example is the main hall of the Qatar University Sports and Events Complex (QUSEC) where, thanks to a combination of hard work, close co-operation and cutting-edge Yamaha and NEXO audio technologies, systems integrator and installer Techno Q deservedly won the award for Best Flexible Space Experience for the project at the 2020 AVIXA AV Experience Awards.

Microphone

How many microphones does AFC Enhance use?

One AFC Enhance system utilizes four microphones for operation. If multiple AFC Enhance systems are needed for a single venue, each additional system will also require four microphones. For detailed examples of microphone and speaker arrangement of a single AFC Enhance system, please ask Yamaha subsidiaries or qualified AFC Enhance tuning partners.

What type of microphone should be used?

In order to realize appropriate system, Yamaha recommends to use the microphone below.

Where should the microphones be placed?

Microphones are fixed to or hung from the ceiling. They must be visible from the source point. They are set at or around the critical distance (Dc) from a representative source point. Environmental noise, especially from heating and air conditioning systems, has to be considered. The reverberation enhancement of AFC Enhance will also increase the SPL of back ground noise. This is not necessarily a problem because it is natural, e.g. if the reverberation time is increased by absorption decrease of absorptive materials, the noise level will increase. However, it is important to prevent excessive noise caused by a direct wind to the microphones or proximity to other mechanical noises. A length of 1.8 meters (6 feet) would be criteria for a sufficient distance between a microphone and a supply opening. For Early reflection enhancement, microphones have to receive the direct sound from a sound source, so they should preferably be set at or within the critical distance (Dc). Microphones must be visible from any point on or around stage area. If the microphone can be set at the Dc, the microphones can be used either for Reverberation enhancement or ER enhancement.

How far apart should the microphones be?

The microphones should be positioned so that the closest microphone-to-microphone distance is no less than half the length of the lowest wavelength you want to enhance. For example, if you want to enhance more than 125 Hz, the distance between the microphones should be greater than or equal to 1.4 meters (4.5 feet).

Loudspeakers

What type of speaker does Yamaha recommend?

For AFC Enhance system, we recommend using Yamaha’s VXS series surface mount speakers, VXC series ceiling speakers, Installation series (IF/IS) loudspeakers, and also NEXO’s iD series and PS series point source speakers. For detailed description of products that are used for AFC Enhance, please refer to the “Lineup” section of the site.

Where should the speakers be placed?

For REV system, speakers should be placed beyond Dc from the listening area to avoid the localization of sound from the speakers. Wall speakers should be facing directly horizontal. The height can be determined by the distance from the nearest seat which should be at or beyond Dc. Ceiling speakers should face directly downward.

How far apart should the speakers be?

For ER system, speakers should be placed on the walls. The speakers should be faced to the audience. The distance between speakers should be between 4.6 to 6.1 meters (15 to 20 feet), which corresponds to Dc. Under a balcony, the distance between the seats and the speakers is often less than Dc. In this case, the speaker distance should be the same as or less than the ceiling height.

What will AFC Enhance NOT do?

- For rooms with excessive natural reverberation, AFC Enhance cannot deaden the space’s reverberation.

- Acoustical anomalies such as excessive reverberation, focused echoes, slap-back echoes, diaphragmatic surfaces, noisy rooms, vibrating or shaking floors or structures, and standing waves or room modes cannot be corrected by AFC Enhance. Traditional acoustical means or solutions must be employed for these issues.

- While AFC Enhance can mask flutter echo, actual correction of the echo problem requires traditional acoustical solutions.

- The primary goal of AFC Enhance is to create natural sounding reverberation that correlates with the visual stimulus from the room. Thus, AFC Enhance will not make one room sound like another such as the Yamaha Artist Services, Inc Piano Selection Studio cannot be made to sound like Stern Auditorium at Carnegie Hall. AFC Enhance’s natural sound is assured because the reverberation tail used to start the AFC Enhance process contains the room’s impulse response signature which is then used to create the additional reverberation in the FIR filters which adds to the reverberant level and further lengthens the tail.