bopro introduces Butyl for manufacturing top-quality speakers. Butyl provides the best of all for the three requirements

associated with world premier speaker surrounds.

1. Light weight
2. High damping property
3. Optimal flexural properties
   
   

1. Light weight. Butyl is tightly controlled for its specific gravity to insure the consistency of the high efficiency. This is an essential and a requirement for the design of a top-line speaker.
2. High damping property. The method used to measure the damping degree of rubber is the rebound. Low rebound means good damping. Butyl has a low rebound and therefore is promptly responsive, precise, and clear. Butyl produces goo-quality sound to satisfy customers¡¥ need.
3. Optimal flexural properties. Although speaker designers have different opinions on flexural properties and material hardness. They do agree that must be able to move freely so that it can provide the necessary mechanical support to handle power loading, and Butyl surround has it all.

Advantages of bopro's Butyl surrounds:

• Environmentally safe
• Thermosetable (from-50¢J to + 130¢J)
• Excellent damping performance - Superior physical properties

bopro introduces NBR surround for the speaker applications. NBR surround provides the three required properties for the world premier speaker surround;

1. Controlled specific gravity
2. Damping property
3. Optimal flexural property
   
   

1. Controlled specific gravity. NBR surround is tightly controlled for its specific gravity to insure the consistency of the high efficiency. This is an essential and a requirement for the design of a top-line speaker
2. Damping property. The method used to measure the damping degree of rubber is the rebound. Low rebound means good damping. NBR has a lower rebound and therefor is promptly responsive, precise, and clear. NBR produces good-quality sound to satisfy customer's need.
3. Optimal flexural properties. Although speaker designers have different opinions on flexural properties and material hardness. They do agree that the cone must be able to move freely so that it can provide the necessary mechanical support to handle power loading , and NBR surround has it all.

Advantages of bopro's NBR surrounds.

• Environmentally safe
• Thermosetable (from-30¢J to + 120¢J)
• Good damping performance
• Good physical properties

PULUX is a thermoplastic elastomer. It is specially developed for speaker surround applications.

Characteristics PULUX has several characteristics which are good for speaker surround requirements.

1. The lightest weight of rubber surround. It has 0.96 of specific gravity, which can meet the high efficiency of speaker design requirement.
2. Optimum damping ¡® excellent fatigue resistance: PULUX is made with two phase materials: one phase provides optimum damping property, and the other provides excellent flexibility and fatigue resistance.
3. Excellent Weatherability: Brittle point of -63¢J and heat resistance of +135¢J provides wide temperature range meeting the toughest weather requirement.

PPM is specially formulated with a unique combination of mineral filled polyolefin. PPM is a composite material specially designed for superior quality speaker cones. Top-speaker designers are in favor to the PPM as speaker cone material because of its outstanding damping performance and high modulus. Mineral in polypropylene is the key to the optimal balance of damping performance and modulus. It provides the low distortion needed for top-quality speaker cones.

The aluminum alloy has density of 2.8, which is a very light and high stiffness metal material. The physical properties are another choice for speaker cone application. The people therefore use the properties for speaker application. The aluminum foil is a good choice for speaker use; there is good sound performance.

The good speaker cone need optimum damping, high stiffness and lighting weight properties. The Sandwich structure provides the physically highest stiffness and lightest weight; the cell structure of honeycomb creates very good damping property. The upper and down layer material could be several options such as kevlar, fiber glass or cloth fabrics. The inner honeycomb material could be Nomex; Aluminum or even resin dipped paper. The Sandwich structure is the ideal material of cone body, but the process and material causes the cone body has higher cost.

The traditional cone paper had been used for speakers more than 50 years. It is take grants to be a good material for cone application. When human being steps into 21 century, the people should seriously consider protecting the environment and the earth. The people should stop cutting the tree for satisfy their ears. The synthetic paper is another choice for human being. Following table is the comparison of synthetic paper vs. traditional cone paper.

Excellent
Fixed material source
Fixed process
No chemicals
No mood problem

The natural fiber cone is our new developed material to replace the cone paper. The material is a natural source, which also won't damage to our environment and the earth. The natural fiber provides good stiffness, lighting weight and excellent damping after proceeding with the resin fixing process. Following table is the comparison of natural fiber cone vs. traditional cone paper.

Bofoam 10P, an open cellular-structure rubber foam, is made by special formulas and foamed by diazo foaming agent (Nitrogen Gas foaming process). There is no "CFC" contamination to the environment. The base material of Bofoam 10P is synthetic rubber, which is completely different from the traditional sound absorbing materials, such as PU foam, wool, Glass fiber wool, and others. The rubber of Bofoam 10P has been vulcanized in the manufacturing process. This is the reason why Bofoam 10P has outstanding physical properties compared with other foam material.

Characteristics

Bofoam 10P has several special characteristics that are difficult to find among other sound absorbing materials. The followings are the characteristics of Bofoam 10P.

1. CFC-free manufacturing foaming process
2. Outstanding low-frequency absorption
3. Flame retardant (ASTM D1692-74)
4. Excellent oil resistance
5. Excellent chemical resistance
6. Corrosion free to cupreous metal
7. Good weatherability (ASTM C548-71)
8. Good shock absorption

Performance

Because of the special formulation and manufacturing process, Bofoam 10P has very outstanding sound (noise) absorption ability compared with other sound absorbing materials. The following data is provided by MECHANICAL INDUSTRY RESEARCH LAB.

Test Method and Results.

A.Equipment and Instrument

• B¡®K 4002
• Function Generator
• Power Amplifier
• B¡®k 3360
• HP9826 CPU
• HP9872C Plotte

B. Test Procedure (Method)

• Sine signals generated by the function generator
• Enlarging the sine signals through the power amplifier
• Sound outputs from the speaker of B¡®K 4002
• Reading the figures from B¡®K 3360
• Calculating and plotting the data in HP CPU system

C. Test Specimen

• PU Foam Sponge
• Glass Fiber Wool
• Bofoam 10P D. Thickness of test material¡G50m/m

Applications

Bofoam 10P can be used in any places where there is a need to reduce or eliminate the sound or noise.

A. Air Condition

• Central control of an air condition system.

B. Appliance

• Air condition
• Refrigerator
• Dehumidifier
• Speakers of TV set
• Speaker cabinets of audio system

C. Electricity

• Diesel power generator system
• Power generator system
• Motor

D. Construction

• Room decoration
• Audio room system

E. Automobile

• Under the hood
• Interiors

Processing

In general case, Bofoam 10P is supplied to customers in foam sheet. Bofoam 10P can be fixed on substance by mechanical method or chemical adhesion. Almost all kinds of adhesives can be applied to adhere Bofoam 10P. The double-side tape is also good in fixing Bofoam 10P on the substance.

*The advantages of bopro's rubber and pulux dust cap

1. Good damping property
2. Good appearance
3. Excellent durability
4. Excellent low-temp. resistance (-60¢J)
5. . Excellent damping stability

*Comparisons between our rubber , pulux and PVC caps on their characteristics¡®performance.

We provide high quality tweeter diaphragm for high performance dome tweeter diaphragm for high performance dome tweeter application. The diaphragm is made by the finest grade of natural silk fabric coated with damping resin.

The factors of high performance dome tweeter.

A. Light, even and consistent fabric or plastic structure diaphragm.

The material of dome diaphragm should be even and consistent. Fabric is a good option for dome diaphragm. The performance of fabric dome diaphragm rely on the damping resin coating and control the modulus of fabrics well.

B. Damping.

The optimum damping resin coating on dome diaphragm is an very important factor in tweeter or mid-range dome. The damping resin coated on fabric diaphragm will make the vibration gradually reduced from voice coil to center of dome diaphragm. The damping resin formulation plays an important role, which should be good consistency ¡® heat resistance.