JBL S4800 manual See Figure

Neodymium

Magnet

Phase Plug

Aluminum

Edge-Wound

Voice Coil

Aluminum-

Alloy Cover

3" (75mm) Pure- Aluminum Diaphragm

Binding-

Post Input

Terminal

Figure 4. Cutaway view of 435AL high-frequency transducer.

is attached to a die-cast alu- minum-alloy frame. This provides accurate, rigid support for the motor and cone mounting points, as well as doubling as a massive heatsink by providing a huge sur- face area for heat dissipation.

The 1500FE has a central cooling duct that effectively cools the voice coil and reduces the likeli- hood of hot spots. By reducing the operating temperature of the voice coil, power compression is signifi- cantly reduced, which enables the low-frequency driver to operate in a more linear fashion over a wider sound pressure level (SPL) range.

The voice coil itself is constructed from edge-wound aluminum wire on a massive 4-inch-diameter fiberglass former. This configura- tion provides for further cooling ability in conjunction with the motor design.

The Aquaplas-coated, Kevlar- composite cone, along with the EPDM rubber surround, provides excellent damping and transient response characteristics.

435AL ALUMINUM DIAPHRAGM/ NEODYMIUM MAGNET HIGH-FREQUENCY COMPRESSION DRIVER

See Figure 4.

The 435AL neodymium high- frequency compression driver is based on the professional JBL 2430 device. It incorporates a rare-earth neodymium magnet structure, designed by extensive computer modeling, including finite element analysis, which combines the attributes of efficiency, strength, low mass and compact size. This motor structure is coupled with

a 3-inch aluminum diaphragm. Aluminum provides improved low- distortion characteristics and flat frequency response.

High-temperature materials and adhesives allow the driver to han- dle extremely high power levels over extended periods of time. The SonoGlass horn is acoustically inert and precision-molded to exacting tolerances.

6