UNDERSTANDING LOUDSPEAKER CABINET VIBRATIONS and how the
vibrations affect loudspeaker sound quality.
When loudspeaker drivers are fed 100 watts, SPL inside the cabinet at times can register
140 dB / 200 pascal / .5 PSI / 72 pounds per square foot which easily
creates enough vibration to the cabinet walls using commonly utilized materials
and thicknesses that the attached drivers distort the sound reproduction.This effect also occurs with in-wall units. Furthermore from the cabinet wall perspective, the SPL is
not smooth-- the waves arrive in Pulses based upon the sound frequency.A 20 hz sine tone will pressure the cabinet
wall 20 times per second and a 20,000 hz sine wave pressurizes at 20,000 times
US Enclosure derived a solution by developing cabinets wall
materials which absorb sound frequencies even at the highest SPL’s and also use
in some cases using just one panel for the entire cabinet—but always using far fewer panels
than required by current materials.Furthermore both the exterior diffraction and the internal
issues degrading sound quality of the least expensive to the most
expensive drivers are also resolved by US Enclosure's technology by
shaped walls both externally and internally which can be mass
manufactured at a
reasonable cost point.
Since 1995 we manufacture cabinet wall materials using 2 factors.
A. Cabinet wall materials which function as an Acoustic Blanket, instead of walls relying only on "Just Mass".
B. Cabinet materials which can be mass manufactured using complex curves to allow low exterior diffraction, low internal reflections and pleasing complex
curved cabinet shapes.
technology is useful wherever higher sound
clarity is required, from cell-telephones to
recording studio monitors to headphones to
home loudspeaker systems to concert
Electromechanical parameters which define the performance of a loudspeaker cabinet material include:
Phase Shift/ Diffraction
Two of our Proprietary Wall Materials, one called
Multi-Modulus and the other named Harmonic Dampening,
are both unlike
any other loudspeaker enclosure
As both materials are specifically designed
absorb internal sound waves using Effective levels of
various material properties in each of several differing layers.
This is Not an Idle
Claim. The finish, strength, and
vibration-absorption characteristics of Multi-Modulus
and Harmonic Dampening are comparable to or surpass the
benefits of any other
loudspeaker cabinet material on the market.
both Multi-Modulus and Harmonic Dampening are especially suited to the challenges of
making loudspeaker enclosures of Any Shape using cabinet
materials that surpass the acoustic qualities of
highest-grade MDF or Plywood-- at a cost equal to these materials, with a finish quality as
good as any wood material. Each material is designed for Constrained Boundary Layer Construction.
US Enclosure has spent 21 years developing loudspeaker cabinet materials by incorporating:
We use all the required engineering elements--
constrained boundary layering, etc. via a potentially single-piece,
multi-layer, thick-wall enclosure with high finish
grades and with Complete Control over all desirable
Unlimited colors and finishes are available with our
well-proven technology system and inherent production
flexibility is designed into the production equipment.
Product performance when viewed from a sound-and-look
perspective will be Equal To or Higher Than to your
current cabinets and are surprisingly cost-effective
compared to your current enclosures.
Our production method has the true potential to dramatically alter
the "look" in the loudspeaker industry and to increase
your company's sales.
We can manufacture virtually ANY Shaped Loudspeaker Cabinet
US Enclosure .44" Cabinet Material in a BOX Shaped Cabinet
compared to MDF or Baltic Birch Plywood .75" Cabinet Wall (BELOW)
Cabinet Frequency Response 8 Hz to 3000 Hz
The MDF Cabinets had the manufacturer's dampening/stuffing for the Test.
Our unit was Without any additional dampening-- Just Bare Walls. All tested used the same driver and same cabinet size.
OUR ENCLOSURE MATERIALS
As OEM loudspeaker
designers/manufacturers, we understand
requirements. We developed a unique
group of loudspeaker cabinet materials after
years of R&D
culminating in a
multi-layer composite material using up to
different components. US Enclosure offers the
specifically designed for loudspeaker
enclosures which can be made into Any
Shape-- from Box to Sphere.
Application. Vented or Unvented.
Wall Materials, called
Harmonic Dampening with optional CBL-- Constrained Boundary-Layer
are specifically designed for Loudspeaker Cabinets.
can have up to
twice the mass of an MDF or
Baltic Birch based cabinet.
Unlike any other quality cabinet wall material, our
can be mass manufactured into
any Curved shape-- finally
loudspeaker manufacturer to easily avoid
damaging transitions ( e.g. edges, slots ) in the loudspeaker
as these transitions themselves
behave as acoustical sources.
from these features always follow the primary
wave in time
and are often reversed in
And with careful design of your cabinet's internal shape, our enclosures
can reduce the @ 50 db reflective
bleed-through from the interior of
the loudspeaker enclosure
through the loudspeaker cones.
The elements we use to Manufacture are simple,
effective and Fully Sound-Tested. Not
only does our wall-materials technology
surpass knock-tests, sound and vibration absorption,
cost is practically the same
as that of wooden box cabinets.
End Result... your loudspeaker system products nearly disappear from
the acoustic soundstage
even when the system uses the least expensive
Our unique enclosure
manufacturing Materials, even with a box-shape,
dramatically increases the look, acoustic quality, and
thus sales performance of your Loudspeaker.
Cabinet Wall Material Physical Properties
Specific Gravity dimensionless
kilogram per cubic meter kg m-3
pound per cubic inch lb in-3
pound per cubic foot lb ft-3
114 (not picture on right)
Multi-Modulus features adjustable densities ranging from in excess of 150 pounds per
cubic foot to as low as 50 pounds per cubic
foot. PHOTO features Multi-Modulus Dyed black on the outside surface and shows photographer reflections. No paint was used.
Harmonic Dampening Cabinet Wall Material Physical Properties
Density for this material is also widely adjustable from over 80 pounds per cubic foot to as low as 10 pounds per cubic foot. Harmonic Dampening material offers this Optional Sound
Absorbing Interior Wall-
This Sample is 124 pounds per cubic foot
(the wood layers and the glue absorb water
from the air)
pound per cubic foot
kilogram per cubic meter
(the wood powder and the glue absorb water from the air)
pound per cubic foot
kilogram/ cubic meter
kg m-3 929.0707
Curved Cabinet Stuffing using Levitated Composite Core
Core Stuffing is
engineered for curved loudspeaker cabinets. Curved interior walls
will focus interior reflected soundwaves toward the center of the
cabinet. Although this system certainly is not required and curved
cabinets can be stuffed in a normal fashion, the engineering takes
advantage of the focused interior soundwaves and places the stuffing
where some of the soundwaves congregate.
Thus some of the stuffing is placed toward the center of the cabinet. (Levitated).
Furthermore as the soundwaves are focused, a composite stuffing material is optimal (Composite).
Following US Enclosure drawings are from September 18, 1993
MANUFACTURING YOUR CABINETS
Enclosure uses a US-based 300,000 Square Foot
production facility with capability of over
2,000,000 loudspeaker enclosures per year.
This plant is the Largest West Coast consumer of our
base-material, with 4 rail
cars of material in-stock.
In today’s rapidly changing markets,
it is critical to speed up development cycles.
US Enclosure’s production techniques enable rapid
prototyping and production runs without the
extremely high cost, slow speeds, or size
limitations of other technologies.
We have very experienced
Subcontractors and materials; ready to manufacture
loudspeaker enclosures for your company.
The manufacturing process for
this technology can be such that the cost impact to
the end user for this added value can be
negligible. If using standard tooling
amortization the cost will be comparable or less
than your current or alternative methods.
The US Enclosure
manufacturing process is inherently superior for
near Total Control over…
Number of layers
Composition of layers
Long or short fiber
strengthening materials, if required
Large or small size
granular strengthening and/or sound absorbing
Sheet materials (if
and other features
useful to the OEM and end-user
NO NEED EXISTS for
deploying YOUR manufacturing to third-world
countries for labor cost reductions. No More 1+ month shipping
times before you can open the container to Inspect
the shipment quality and no surprises when your
products reach your docks. No overseas
shipping costs. We offer stable product
supply with delivery times you choose and without
shipped product defects, at a True Cost which is far
lower than any third-world country's
production. China and many other third-world
countries produce shipped products with 25% Defect
Rates while mass-polluting the local ecology and
paying starvation-level wages to their
manufacturing process is the BEST ALTERNATIVE
for Loudspeaker Production...
We have the Experience to properly execute our
clients exacting & demanding mass-manufacturing
requirements. From 1990 through today,
we perform research and development on loudspeaker
lines using our unique loudspeaker enclosure
materials. And until 2002 we had our own line of
loudspeakers; we understand the OEM loudspeaker
industry. When we became 100% OEM
Subcontractor, we already had located the best
subcontractors to manufacture our materials for you.
When contracted by your company, we apply intensive
R&D and exhaustive testing to finalize the
process to beat your expectations, with results we
both can believe in and are both proud of. In
1990, we approached the problem by looking at the
driver housing as...
(1) dealing with the sonic back wave launched by the
driver into the enclosure, and (2) allowing cost-effective OEM manufacturing of
cabinet shapes that will minimize external
diffraction and distortion.
The two major drawbacks of using an MDF or Baltic
Birch box is that MDF can not be made into non
diffracting shapes and also exhibits a series of
strong resonance's in the 250 - 750Hz region as well
as an acoustic window in the 14,000HZ range.
Our enclosure materials works with stuffing by
efficiently converting back wave sound energy into
heat by using viscoelastic properties and laminated
compounds, dissipated evenly throughout the outer
layers of the cabinet. This process is further
assisted by the available non-symmetrical internal
shape and wall thickness, which also defeats
internal diffraction and sound wave reflections back
through the loudspeaker cones.
We believe all loudspeaker cabinets are active
components of a sound system, and important to the
overall sound as the cabinet is an active energy
conversion system. Its job is to contain and convert
energy. It must deal with the back-wave
produced by the drivers it houses. Recalling
that the back-wave inside the cabinet has just as
much force the sound emanating into the room will
both reflect through the loudspeaker cones as well
as energize the cabinet and cause resonance.
In order to create an acoustically inert cabinet
that is also non diffracting, and,
cost-effective for an OEM, one must apply creative
engineering solutions to supply the best product
possible then provide our clients with a 24/7 level
of backup and service.
cabinets are produced in molds, we strive for no
more than 2 Piece cabinets; standard box cabinets
have 6 pieces. Fewer vibrating panels have
obvious benefits for sound quality. Curved
enclosures have the added benefit of a stronger wall
than the same as a flat piece made of the same
One could wish
for single-piece enclosure construction with no
seams, discontinuities, or other imperfection.
It's possible and perfect for loudspeaker
enclosures-- and ages of high strength engineering
tell us that multiple material layers and special
chemical processes are required to achieve the
Composite Fabrication has an
illustrious role in human civilization, and
has many applications where sound, vibration, and
strength are key issues. US Enclosure has
developed the best loudspeaker enclosure materials
available and they can be mass-manufactured to your
current specifications or your Dream Specifications.
COLOR, FINISH AND APPEARANCE
The cabinet will have a superior
finish and can smoothly blend into existing architecture
or decor. Custom colors and finishes are
available, unmatched by any other manufacturing
technique. The finish can be easily cleaned.
The product is rated for both exterior or interior use,
enhancing the visual appearance of either architecture
or interior design.
CONCURRENTLY, Your product will deliver superior
acoustic performance compared to regular loudspeaker
cabinets available on the market.
Nearly Unlimited Class A
The following chart describes the
various color and finish options:
Varies from high to satin to matte.
perfect white isn't always achievable
out-of-mold. However we can
infinite color palette for the cabinet
can be textured in a variety of ways.
variety of veining options exist.
available in various
the appearance of Gold, Silver, Copper
or other metallic hues. Exotic
two-tone's are also available as well as
Young's modulus, also known as the tensile modulus or
elastic modulus.Young's modulus is
the most common elastic modulus, sometimes called the modulus of elasticity,
but there are other elastic moduli measured, too, such as the bulk modulus
and the shear modulus.Elastic
modulus, or modulus of elasticity, is the mathematical description of an object
or substance's tendency to be deformed elastically (i.e., non-permanently) when
a force is applied to it.The Bulk
Modulus (K) describes volumetric elasticity, or the tendency of an object to
deform in all directions when uniformly loaded in all directions; it is defined
as volumetric stress over volumetric strain, and is the inverse of
compressibility. The bulk modulus is an extension of Young's modulus to three
In linear elasticity, the Lamé
parameters are the two parameters
•λ, also called Lamé's first parameter
•μ, the shear modulus or Lamé's second parameter
(also referred to as G)
•In homogeneous and isotropic materials, these satisfy
Hooke's law in 3D,
In linear elasticity, the P-wave
modulus, also known as the longitudinal modulus or the constrained
modulus, is one of the elastic moduli available to describe isotropic
homogeneous materials.It is defined as
the ratio of axial stress to axial strain in a uniaxial strain state.