Technology - VA4

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VA4 - The Fourth Dimension


VA 4™ Technology While Virtual Array™ Technology significantly reduces interaction between arrayed enclosures in the horizontal plane, VA4™ Technology extends array control to the vertical plane. Simultaneously, VA 4™ technology also solves the fourth dimension problem in audio: Time. A True Point Source Developed for the KF750 Series, VA4 technology unifies the space/time origin over the entire audible spectrum. This eliminates the temporal smearing plaguing previous loudspeaker designs. With a broadband, unified wavefront, clarity and impact are significantly enhanced. Essentially, the KF750 is a very large MF horn with the LF and HF subsystems mounted within its flare. Since all three subsystems' acoustic centers are on the same axis, appropriate signal delay creates a unified space/time origin for the entire system. This results in a three-way array system that acts as a true point source.
It's About Time Unlike the relatively smaller geometry of a compression driver's diaphragm, there is a slight but noticeable difference in the sonic origins of a cone transducer's dustcap, cone, and edge surround. Particularly in the upper midrange, these different origins cause differences in arrival times at the listener resulting in a "smearing" of the attack of sounds (transients). This smearing effect degrades the clarity and impact of the sound. Furthermore, these differences in arrival times can affect overall fidelity even when out of the passband and substantially lower in level. To remedy this problem the KF750 incorporates EAW patented Radial Phase Plug™ Technology into the loudspeaker's midrange subsystem. This radial slotted phase plug eliminates temporal smearing for astounding, unsurpassable intelligibility.
The KF750 Full Range Loudspeaker Array Module is essentially a very large mid frequency horn with the low and high frequency subsystems mounted within its flare. Since all three subsystems' acoustic centers are on the same axis (as shown at right), appropriate signal delay creates a unified space/time origin for the entire system making it the only three-way array system that acts as a true point source. While the Dipolar Array LF section's dual woofers are positioned above and below the mid/high axis, their acoustic center is exactly on that axis. Since all acoustic centers are on the same line, simple signal delay makes the entire broadband audio image originate from one specific location at one specific point in time. Acoustic Singularity design makes this the first and only three-way concert touring array module that acts as a true point source. This advancement increases clarity and impact of all sonic events and greatly improves array performance.	The KF750 shown in a cutaway view to illustrate Acoustic Singularity design.
The VA⁴mid cone and phase plug shown in exploded view.	It's About Time Unlike the relatively simple geometry of a compression driver’s diaphragm, there is a slight but noticeable difference in the point of origin of a cone driver’s dustcap, cone, and surround. Particularly in the upper midrange, these differences create a “smearing” of arrival times at the listener that degrades the clarity and impact of mid-frequency sonic events: most notably vocal reproduction. Because they are what the ear hears first, early arrivals out of the passband can affect overall fidelity even though they are substantially lower in level.
The distance from a cone driver’s voice coil to its dustcap is shorter than the distance from the voice coil to either the cone or surround. Therefore, the energy radiating from the dustcap most often leads the energy from the rest of the system. Traditional phase plug designs have isolated this energy and routed it through a longer path than that which faces the energy from the cone or surround. In so doing, the phase plug attempts to equalize the arrival smear. Conventional phase plug designs use a circular entrance and exit to the phase plug, converting the output from a point source into a ring radiator. A ring radiator, however, exhibits a more dramatic narrowing of beamwidth with increasing frequency than a cone transducer. Thus the mid frequency device’s directivity narrows to the point where it no longer fills the bell of the horn, leaving upper mid holes in the frequency response on the seams of an array. The KF750 mid/phase plug assembly attacks the problem at the source, precisely aligning the cone/dustcap/surround geometry to maintain temporal unity. The phase plug, whose geometry is matched to the cone, then serves to leave this unity intact. Expanding radial slots within a compressing frame lower the mechanical reactance of the load facing the transducer without modifying the directivity associated with the source. This allows for faithful reproduction of upper mid frequencies without any narrowing of beamwidth. KF700 Series: VA4 for general purpose applications The KF750 is the high "Q" full range loudspeaker system that serves as the primary array building block. Even with its exceptional long throw capabilities, its smooth power response and coherent tonal quality allow it to work in nearfield applications as well. At its core, a KF750 is a very large mid frequency horn. Allowing the horn to fill nearly the entire front of the enclosure enhances pattern control in the lower midrange, minimizing interaction between adjacent modules. The 10-in mid frequency cone transducer and phase plug assembly was developed specifically to eliminate the temporal smearing that degrades vocal intelligibility in all other array systems. It is so unique that US and international patents are pending. The high- and low-frequency subsystems fit within the mid horn, minimizing both size and weight. The KF755 provides dedicated downfill coverage in array configurations where trim height requires additional nearfield output. The KF755 can be inverted to provide upfill to auditorium balconies and can even be used as a stand-alone system in applications requiring that coverage angle. In addition to the single 12-in woofer, it contains the same mid and high frequency transducers as the KF750 loaded on vertically asymmetrical horns. The MQ Series: VA4 for permanent installation EAW's MQ Series of mid/high VA4 modules is engineered solely for optimized performance in permanent installations. Portability played no part in its design. By allowing the mid- and high-frequency horns to expand to their optimal sizes achieved two important goals of VA4 Technology: expanded the frequency range of the system's pattern control smoothed power response to a lower frequency The MQ Series uses the patented VA4 10-in mid frequency cone/radial phase plug assembly. This design uses a more logical cone geometry than previous designs to achieve a significantly more unified arrival over the upper portion of the mid frequency band. Low frequency output is provided by dedicated MQ Series LF modules or TD Series Tuned Dipolar Array™ systems. Sound system designers use these systems to create precision arrays for arenas, stadiums, theme parks or any large space where oratory or musical performance is given.

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