KRK E8B manual Design Elements, Enclosure, Amplification, Tweeter

Page 5

Design Elements

The Enclosure

The contoured shape of the Exposé E8B enclosure creates a striking appearance; however, its design is every bit as functional as it is beautiful. More rigid than conventional rectangular designs, it improves the linearity of the bass response, and increases off-axis response, resulting in a wider sweet-spot. The E8B’s gently curved front baffle and wide-radius edges reduce the diffraction effects for better imaging.

Cabinet rigidity is extremely important to a loudspeaker’s performance characteristics. A properly designed enclosure should not resonate and produce its own sound. All sound should emanate from the transducers and be focused in a single direction—from the front of the cabinet. With its non-parallel, internal walls, the E8B reduces the chances of standing waves inside the cabinet. The thinnest point in the construction of the cabinet walls is 1-inch. Further, the thickness of these walls is continuously variable due to the curvature of the enclosure’s exterior, which also helps prevent any resonant buildup in the walls themselves as a result of sound that is being transmitted from the drivers. Further, the base of the E8B is made from a non-slip, sound absorbing rubberized material that eliminates vibrations transferring to the surface the monitor is sitting on as well as insuring the enclosure will not “drift” on its pedestal, or mounting stand.

The Exposé E8B is video shielded to ensure maximum protection against magnetic interference with video monitors.

IMPORTANT NOTICE: These monitors are heavy! Please use care in handling them and ensure that the enclosure is placed on a suitable surface capable of supporting the weight.

NEVER TOUCH THE TWEETER ON YOUR E8B MONITORS, AS THIS CAN DAMAGE THE TWEETER MATERIALS BEYOND REPAIR.

Amplification

As a 2-way design loudspeaker, the Exposé E8B utilizes two discrete, 120-watt (RMS) Class A / AB power amplifiers. The system runs Class A up to approximately 8 watts (the crossover point). This is a dual mono system—one amplifier each for HF and LF— with symmetrical heat sinks built into the sides for cool running, reliable operation. Special circuitry in the E8B eliminates turn on/off “thumps.”

The Exposé provides maximum circuitry protection against AC power surges, amplifier DC output, and thermal overheating of the amplifiers.

The Tweeter

The HF tweeter in the E8B is made from beryllium and aluminum in a composite material known as AlBeMet. The aluminum in this composite helps dampen the metallic characteristics of pure beryllium. The advantage of beryllium over the more conventional titanium-type tweeter is very high stiffness to weight resulting in an extension of frequency response, thus increasing the overall bandwidth of the monitor. The resonances that occur with beryllium are far beyond the normal human hearing range; hence, this eliminates any other second or third order harmonic distortion that is audible in the normal listening registry. Further, the voice coil diameter on this tweeter has been increased, resulting in improved power handling capability. The resonant frequency has been lowered which improves the phase relationship.

5

Image 5
Contents P O S É Page Introduction Spectral Balance Timbre Design PhilosophyDistortion Management Resonance ManagementEnclosure Design ElementsAmplification TweeterHF Shelf Switch System Level AdjustRear Panel Controls WooferHF Level Adjust Connecting Your SystemLF Adjust Voltage Select Switch for AC MainsPositioning Your Monitors Installing Your MonitorsLow Frequency Adjustment Considerations Channel Setup Channel Surround Sound Setup Subwoofer SetupChannel Surround Sound Setup Page Problem If the monitor suddenly stops working… Problem If you can’t hear any sound…Problem The sound quality changes… E8B Powered Studio Monitor Specifications