General Description

Foamex acoustical materials are designed to perform a number of specific and seemingly opposite acoustical functions...ether reducing sound levels, or passing sound undistorted and undiminished...each determined by both the basic of the foam and its method of application. Certain non-reticulated foams are ideal for sound absorption and attenuation. Reticulated foam can absorb sound very effectively or can be completely acoustically transparent. Noise absorption applications include: commercial aircraft ventilation ducts; headliners and back panels for tractor cabs and off-road vehicles; data-processing equipment; portable air compressors and power units; appliances; snowmobiles; as well as headliners and panels for automobiles. Sound fidelity applications include; stereo speaker grilles, earphones, and microphone covers. Benefits included are: predictable sound absorption in board band(low, mid, high) frequency range from engineered foam grades; nearly "total perfection in sound transparency application (polyurethane foam is 97% air) from other selected grades; fabrication design flexibility; functional/decorative laminate capabilities; installation ease; excellent shape retention, and resistance to wear and abrasion.

 

Noise Absorption 

Acoustical foam will absorb the activity of airborne or fluid-borne noise, causing a loss in energy by weakening reflected vibrations. The sound vibration pulses are literally "tired out" by their effort to force the foam strands to vibrate...and the noise reflected level is, therefore, immediately reduced. Acoustical foam for sound absorption provides the foam high efficiency, consistent throughout, and predictable from installation to installation.

 

Applications Include

Automobile headliner, truck, tractor, off-road vehicle cab liners, office equipment, industrial machinery, marine applications, anechoic test chambers.

 

Acoustical Functions

Product

Function

Application

*SIF (Fine & Coarse Pore)

Sound Absorber

Anechoic chambers and noise test facilities

*SIF (Medium Pore)

Air Diffuser

Microphone wind screen covers,

power brake units, mufflers

*SIF II (Medium Pore)

Acoustically Transparent

Hi Fi speaker grilles

*SIF Felt

Sound Absorber

Tuned for mid and high frequencies

*Aerofonic

Sound Absorber

FAR 25.853 extened environmental

use felt designed for aircraft

**Aresto II

Sound Absorber

General use where flammablily

and economy are important

**Pyell

Sound Absorber

General use where maxium flammablily

protention is a concern

Hyfonic

Sound Absorber

An extended environmental foam where

flammability is a concern

Fine-Pore Acoustical

Sound Absorber

General use where economics is

the major concern

Custom Lamination

Sound Absorber

Where special barriers are needed

and/or aesthetics are important

Moisture Barrier

 

CX

Sound Absorber

A slow recovery, damping,

acoustical absorbing foam

*Engineered to be predictable from to run based on close tolerances, for density permeability and fores per lineal inch

**Available in 4 lb/ft2 density

 

Typical Physocal Properties of Foamex Acoustical Materials 

 

SIF Industrial

Foam

SIF Felt

CX

Aresto II

Pyell

Hyfonic I

Aerofonic Felt

Grade

(PPi)

90

3-900

70

70

70

65

4-700

Density

(lb/cu. ft)

1.9

n/a

3.5

2.0

2.0

1.7

n/a

Tensile

35

n/a

13.0

20.0

22

14

n/a

Strength

 

 

 

 

 

 

 

Elongation (%)

415

n/a

195

190

220

 

n/a

Tested in accordance with ASTM 3574. Physical properties not to be used as a specification

 

Vibration Isolation 

Noise transmission sound barriers are used to reduce the noise level being transmitted through a housing when the housing itself does not satisfactorily perform that function. When noise levels are severe, an additional high mass transmission reduction wall or septum is often required. Acoustical from is applied as a decoupler between the housing and the inner septum, and as an absorber on the outer septum wall, to effectively absorb and reduce the noise energy flow.

 

Applications Include

Acoustical panels, aircraft, turbine engines, broadcast studios' data processing equipment, power generator housings, automotive headliner.

 

Vibration Damping

Acoustical foam are used to reduce vibrations of physical structures that, in run, produce noise due to that vibration. In some cases, for maximum vibration reduction, acoustical foams are used conjunction with a damping layer, such as a viscoelastic material.

 

Applications Include

Air conditioning equipment, dishwashers, aircraft compartments, high-speed rail cars, data processing machines, enclosed power units, engine housing.

 

Sound Fidelity

Reticulated acoustical foams have been proven virtually acoustically transparent; effectively invisible to sound waves in audible frequencies. This is true even of foam two inches thick. A leading California stereo speaker manufacturer made this fact well-known by introducing a line of speaker that offered nearly perfect sound transparency through striking design-sculptured foam grilles in a variety of colors.

 

Applications include

Stereo speaker grilles, earphones, microphone windscreen cover, smoke alarm grilles,

 

Acoustical Foam Types Industrial Foam (SIF)

SIF is reticulated, 90 pores-per-linear-inch (ppi) polyurethane foam with excellent uniformity and predictability. It is particularly effective where it can be used in a thickness above two inches...in the anechoic chambers of sound testing facilities, for example.

 

SIF Felt Acoustical Foam

SIF Felt is 90 ppi reticulated foam that has been permanently compressed by both heat and pressure; sound absorption properties can be tuned to selected frequencies by specifying thickness and final felt "firmness grade." SIF Felt is specified where both space and predictable performance are important factors.

 

Custom Lamination

perforated vinyl, Mylar adhesive, or other approved substrates, can be specifically flame-bonded to Foamex acoustical materials according to specific customer needs.