What is Diffusion?

In the world of audio, more specifically – the physics of audio, sound diffusion is the act of evenly spreading or “scattering” sound waves throughout a given space.  When a sound wave hits a flat surface, the result is a reflection of that sound wave which can cause echoes, and diminish the quality of the audio within a listening environment.

Diffusion is typically achieved by using Sound Diffusers, which feature a smooth, hard surface (convex or concave) to uniformly scatter the sound at reflection points.  They are typically made of hardened fiberglass, wood, or sometimes plastic or PVC.  Each application is unique to the specific room, but diffusers are commonly utilized on both walls and ceilings to achieve an even distribution of sound at any listening point in a room.

Why is Diffusion Needed?

Rectangular rooms with parallel walls commonly experience “slap echo”, or sound waves bouncing off the parallel surfaces.  Slap echo can interrupt a sound field by destroying the critical phase relationships necessary to develop an accurate sound stage.  These disruptions can be dreadful for environments such as home theaters, recording studios, mixing control rooms, music venues, auditoriums and gymnasiums.

We have all attended an event inside a noisy gymnasium, untreated concert venue, loud auditorium, or been to a restaurant where it is hard to hear the person next to you because of sounds bouncing all over the room.  These reflections and echoes make it very hard to decipher speech, and can hinder overall audibility within a room.  This is why absorption and diffusion are both necessary to achieve a well-balanced, high-quality sound.

Different Listening Environments, and Simple Guidelines

Home theaters, control rooms, and listening rooms can all differ in requirements for proper diffusion.  This is all dependent on the sound field that you are trying to create, the shape of the room, and the sound source.  Without getting too in depth, here are some simple guidelines to consider when investing in, and installing sound diffusers in each of these environments.

• Be mindful of where the sound source is located in the room
• Address areas of the room that experience “slap echo”
• Prior to installing diffusers, make note of each “dead spot” within the room
• Consider locations on the ceiling, where diffusion is needed
• Take the shape of the room into account
• The rear wall, behind the listening position, is the most essential area to add diffusion – next, the front wall and ceiling need to be addressed

Conclusion

The overall goal of sound diffusion is to reduce unwanted echoes and reflections, to fully develop a sound stage, and evenly distribute the sound throughout a listening environment.  Proper diffusion will result in the room sounding larger, or livelier, and will make it seem like the walls and ceilings have “disappeared”.  This is a result of the diffusers “expanding” the proximity of the room, and creating a more even sound stage.

Sound Acoustic Solutions offers two types of sound diffusers – Barrel & Pyramid shaped.  These products both work extremely well on walls and ceilings, and are sold in a standard 2′ x 2′ or 2′ x 4′ size to fit directly in grid ceilings.  They are made up of a rigid E-glass, and are finished with a white gel coat.  Need a quote?  Request a FREE quote by clicking HERE.

For other products related to enhancing acoustic performance, click HERE.

Sources:

Acoustic Fields – How do Sound Diffuser Work?

Acoustic Geometry – Where to Place Sound Diffusers

SoundAssured – Where to Place Acoustic Diffusers in a Room

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