Read the July 2015 Voice Coil Magazine article.

Technology and Capabilities:

Topics addressed include:
Technology & Capabilities, Materials, Finishes & Colors, Construction, and Product Manufacturing

CALCULATING AND 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 per sec.

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 reflection issues degrading sound quality of the least expensive to the most expensive drivers are also resolved by US Enclosure's technology by manufacturing curved 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.

Some End Users and Manufacturers

  Concepts include:
Acoustically Engineered Constrained Boundary Layer wall materials

Our technology is useful wherever higher sound clarity is required, from cell-telephones to recording studio monitors to headphones to home loudspeaker systems to concert reinforcement.

Electromechanical parameters which define the performance of a loudspeaker cabinet material include:

CABINET MATERIAL   Capacitance Resistance

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 manufacturing material

As both materials are specifically designed to 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.

And Importantly. 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:

(1) Young's modulus,
(2) Lamé parameters,
(3) Bulk modulus
, and
(4) P-wave modulus

to develop the best Composite Loudspeaker Cabinet Materials for each cabinet application. [1]

D'Appolito Sphere cabinets with 5/8 inch walls denser than MDF or Plywoods

VIDEO:  6000 pound Truck drives onto an old US Enclosure Cabinet with a 1/4" wall
Do not attempt this-- with a 1/4" wall wood or metal cabinet
This demonstration does not utilize our strongest material; Engineer all our loudspeaker cabinet walls for strength and vibration resistance... into Any Shape.

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 acoustic characteristics.

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

                               Cabinet Frequency Response 8 Hz to 3000 Hz Sweep

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.



As OEM loudspeaker designers/manufacturers, we understand
loudspeaker manufacturing 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
6 different components.
US Enclosure offers the only loudspeaker
enclosure material specifically designed for loudspeaker
enclosures which can be made into Any Shape-- from Box to Sphere.
Any Application.  Vented or Unvented.

Proprietary Cabinet Wall Materials, called Multi-Modulus and
Harmonic Dampening with optional CBL-- Constrained Boundary-Layer
are specifically designed for Loudspeaker Cabinets
.  Enclosure walls
can have up to twice the mass of an MDF or Baltic Birch based cabinet.

Unlike any other quality cabinet wall material, our wall materials
can be mass manufactured into any Curved shape-- finally
allowing a loudspeaker manufacturer to easily avoid acoustically
damaging transitions ( e.g. edges, slots ) in the loudspeaker cabinet
as these transitions themselves behave as acoustical sources.
Arrivals from these features always follow the primary wave in time
and are often reversed in polarity.

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, the manufacturing
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 drivers.
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


Baltic Birch:

(the wood layers and the glue absorb water
from the air)

Specific Gravity
pound per cubic foot
lb ft-3
kilogram per cubic meter
 kg m-3


(the wood powder and the glue absorb water from the air)

Specific Gravity
pound per cubic foot
lb ft-3
kilogram/ cubic meter
kg m-3

Curved Cabinet Stuffing using Levitated Composite Core

Levitated Composite 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


US 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… 

     Wall thickness Wall Stiffness
     Number of layers Damping factor
     Composition of layers Long or short fiber strengthening materials, if required
     Large or small size granular strengthening and/or sound absorbing materials Sheet materials (if moldable)
     Finish quality 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 employees.

OUR 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,
(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. 



As our 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 material.

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 ultimate product. 

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. 


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 Enclosure Finishes
The following chart describes the various color and finish options:

(Gloss) Varies from high to satin to matte.
Brights       A perfect white isn't always achievable out-of-mold.  However we can control the
brightness level.
Colors Virtually infinite color palette for the cabinet walls.
Exterior can be textured in a variety of ways.
Veins A variety of veining options exist.
Granules Granules available in various reflectivity's.  (Stone Appearance)    
Give the appearance of Gold, Silver, Copper or other metallic hues. Exotic two-tone's are also available as well as actual Mirroring.




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 dimensions.

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.