User manual JBL 4344MKIIL

[. . . ] The cone is a rigid paper composite, treated with AquaplasTM for strength, speed, and damping. JBL's Symmetrical Field Geometry is employed in the form of an aluminum sleeve around the pole piece. This sleeve reduces second-order distortion through induced flux control. Its aluminum composition is also a more efficient conductor of heat, so it assists in dissipating heat away from the voice coil to extend the power capacity. [. . . ] Titanium possesses the essential requirements for a high-frequency transducer. The goal is to maintain a piston-like action as high in frequency as possible. Should the material flex easily, the diaphragm will break up into random vibrations. Second, titanium is virtually immune to fatigue, unaffected by the cumulative effect of millions of flexures over long operating periods. These factors coupled with the higher power handling that titanium affords, allow us to produce an extremely smooth highfrequency transducer with extended frequency response that can handle all the demands of today's digital programs. The Horn/Lens assembly ensures controlled distribution of the high frequencies, resulting in a wide soundstage with pinpoint imaging. No. 5 ultrahigh-Frequency Transducer For the ultrahigh-frequency transducer, we chose a 1-3/4" compression driver with an edge-wound aluminum voice coil. This driver reproduces all of the ultrahigh frequencies above 8000Hz with incredible clarity and detail. Dividing Networks The job of the dividing network is to distribute the various frequencies to their respective transducers. The network is also designed to complement component location on the baffle. Slopes are chosen to match the exact response of each driver in its respective frequency range, as well as to ensure that the high-frequency transducers are adequately protected from dangerous low-frequency components. For the 4344MkII system, we chose our Charge-Coupled Linear DefinitionTM Dividing Network. The inductors are all designed for highcurrent, low-distortion operation. Connecting the systems in this manner ensures that they will operate in phase; that is, they will work together rather than in opposition. Connecting the speaker system out of phase will not cause damage but will adversely affect the speaker's sound. Figure 3 Connections Bare Wire Connecting Method JBL INCORPORATED 8500 BALBOA BLVD. NORTHRIDGE, CA USA HIGH FREQUENCY LOW FREQUENCY Banana/Spade Connecting Method JBL INCORPORATED 8500 BALBOA BLVD. NORTHRIDGE, CA USA HIGH FREQUENCY LOW FREQUENCY No. 9 Figure 4 Standard Connecting Method JBL INCORPORATED 8500 BALBOA BLVD. NORTHRIDGE, CA USA HIGH FREQUENCY LOW FREQUENCY Bi-Wiring The 4344MkII's outer connection panel and internal dividing network are designed so that separate sets of speaker cable can be attached to the low-frequency transducer and midrange/high-frequency transducer portions of the dividing network. Bi-wiring can provide several sonic advantages and considerably more flexibility in power amplifier selection. The advantages of bi-wiring are as follows: Reduction of Intermodulation The majority of current flowing between an amplifier and speaker is devoted to bass reproduction. In fact, 60% or more of an amplifier's output is destined for the woofers. When current flows through a wire, it produces an electro-magnetic field (EMF) that expands and collapses at a rate equal to that of the music's complex frequency components. If a single speaker wire must conduct the full musical frequency, the preponderance of lowfrequency information can interact with or modulate high frequencies. The resulting intermodulation can create audible changes to the high frequencies even before they reach the loudspeakers. [. . . ] For passive and bi-wire connections, set the switch to the Normal/Bi-Wire position (Figure 5a). The external "strapping bars" that normally connect the 4344MkII low-frequency and high-frequency terminals must be removed before bi-wiring. To remove the shorting straps, simply loosen and slide the bars off to the side (Figure 8). Never connect two amplifiers to the same loudspeaker without first removing the strapping bars. [. . . ]