Conventional
acoustic treatments have relied on absorption for reflection
control.
Unfortunately, this can "deaden" the room and make it unsuitable
for speech
or music. Diffusive ceilings are one of the most effective ways
to simultaneously
control room reflections and provide a natural ambiance. The
Omniffusor® uniformly scatters sound arriving from any direction
into many directions, providing ideal distribution and coverage.
It’s
unique shape creates an attractive, visually interesting
acoustical surface.
Problem
Specular reflections from flat, hard surfaces cause strong
reflections
that corrupt speech intelligibility and degrade music quality.
Typically,
fabric wrapped absorptive panels are used to control interfering
reflections,
but in some situations the deadening effect is undesirable.
Solution
The Omniffusor® is the first two dimensional QRD® sound diffuser
of its kind. It offers twice the reflection
attenuation of the 1D QRD®, because it scatters sound uniformly
into
a hemisphere. The Omniffusor® provides uniform, omnidirectional,
broad bandwidth diffusion in an attractive ceiling or wall
design element.
Absorption
It was discovered that phase gratings,
consisting of wells of
different depths separated by dividers, also may provide sound
absorption.
The absorption is caused by viscous losses created by high
particle velocity
flows over the dividers, between wells of different depths and
resonant
frequencies. The absorption can be enhanced by placing a
resistive element,
e.g. fabric, near the face of the phase grating. A supplemental
sound absorption data sheet illustrates
the absorption performance uncovered, with fabric directly on
the surface
and at 2" and 7" above the surface.
Diffusion
The Omniffusor® offers significant
diffusion above the diffraction limit of 565 Hz, which is
determined by the
dimensions of the panel. The chart displays the mean diffusion
coefficient, which is the normalized standard deviation of the 1/3
octave polar responses for angles of incidence between 0° and 90°, the
normalized scattering coefficient for computer modeling calculations and
the A-mount absorption coefficient for reference.
Installation
Wooden Omniffusors® can be wall
mounted.
For wall installation, plexiglass Omniffusors™ should be flush
mounted
into a framed opening. Decorative trim can be added to conceal
the perimeter
joint.