JBL S4800 manual See Figure, 1500FE LOW Frequency Driver

Figure 2. Height of S4800 speaker system in relation to listener.

the sound seems to come from the combination horn. Music imaging is more realistic since the sound appears to emanate from one point and not from multiple points at dif- ferent times.

The S4800 is a constant-angle sys- tem without regard to frequency. Careful horn design enables the loudspeaker to strictly adhere to a 100° horizontal/60° vertical cover- age pattern. This controlled cover- age arrangement precisely defines the optimum listening area and minimizes room effects. At the

The following sections describe the primary features and compo- nents of the S4800 loudspeaker system.

The enclosure of the S4800 is specially designed to transfer unwanted mechanical energy away from any acoustically active surfaces, virtually eliminating coloration.

The massive enclosure, along with its specially designed brass modular feet, couples directly to the floor, and the system literally becomes a structural part of its environment. Any vibration is transmitted harmlessly down the

Thanks to the combination horn, both the UHF (ultrahigh-frequency) and HF (high-frequency) drivers are located at the ear level of the listener.

See Figure 2.

The large 3-inch HF transducer allows the 15-inch woofer to be crossed over at a frequency low enough to eliminate any audible effects of its exact location and proximity.

Full image coherency is main- tained, resulting in an acoustically stable pinpointed stereo image. All

same time, it provides a generous “sweet spot” for more comfortable critical listening sessions.

THE 1500FE LOW-

FREQUENCY DRIVER

See Figure 3.

In order to achieve the lowest pos- sible distortion and compression along with the high linear excur- sion necessary, the 1500FE is equipped with a ferrite magnet. As with earlier JBL low-frequency drivers, it utilizes forced-air cool- ing. The entire magnetic structure

channel provided by the ring/ disc axes and into the floor. The SonoGlass combination horn maintains a smooth energy transmission path.

The S4800 transducer/enclosure arrangement represents the best possible balance of the various tuning options and avoids the mid-bass response buildup found in other vented systems. Response works with, rather than against, the effects of “room loading.”

The unique design of the system is the platform for its equally unique acoustical attributes.

Surround: EPDM Foam Rubber

Pigtail Leads:

Silver-Plated

Cadmium Copper

w/Conex Core

Spiders:

Nomex®

Dust Dome:

Paper-Pulp

Composite

Spider Spacer:

Extruded Aluminum

6063

Trim Ring:

NBR Rubber

Frame:

Cast 380

Aluminum

Terminal Base: Glass-Filled ABS

Cone Body:

Special Paper-

Pulp Composite

Terminals:

Gold-Plated 5-Way

Binding Posts

Magnet:

Ceramic

olepiP ece: teelS SAE-1008

Back Plate:

Steel SAE-1008

Pole Sleeve: High-Purity Copper

Voice Coil:

Aluminum Ribbon Wire ES-1350 on High-Temp Fiberglass Former

Figure 3. Cutaway view of 1500FE low-frequency transducer. 5