3.0 Designing an EVF/EVH Cluster (cont’)

3.5 Multiple-Source Interference in Clusters

Whenever two or more sources serve a single venue, some seats will receive strong signals from multiple sources. Consider two EVF-1122S/64 60° x 40° systems clustered side by side with their axes 60° apart to form a 120° x 40° cluster. If these systems maintained their rated coverage patterns into the low- frequency range, there would be essentially no interference. But the 12-inch-square waveguides used in the EVF series will begin to “balloon out” at about 2 kHz and below, an effect discussed in Section 3.21 Directivity Break Frequency Defined, above.

On the axis of the cluster, the output of both systems sums perfectly, since the listener is equidistant from each system and the output of both reaches the listener at the same time. This is the axis-of-cluster line shown in Figure 4. If the listener moves to the left (as viewed in the figure), the left loudspeaker will be closer and the sound will arrive sooner. At some angle and at some frequency, the time difference will be equivalent to reversing the polarity of one signal, causing a complete cancellation of cluster output at that frequency.

Figure 4:

The two loudspeaker sources sum perfectly only on the axis of the cluster (as shown); to the left and right of this axis, distance differences produce arrival-time differences that cause cancellation of some frequencies (see text for more details)

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Electro-Voice EVF/EVH User Manual

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Electro-Voice EVF-1122D, EVF-2121S, EVH-1152S, EVF-1152D, EVF-2151D, EVF-1181S Multiple-Source Interference in Clusters
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EVH-1152S, EVF-1152S, EVF-1122S, EVF-1122D, EVF-1152D specifications

Electro-Voice is renowned for its high-quality audio solutions, and the EVF series embodies this commitment. The EVF-2121S, EVF-1121S, EVF-1181S, EVF-1151S, and EVF-2151D are a collection of loudspeakers designed for a variety of professional audio applications, each with its distinctive features and capabilities that cater to different sound reinforcement needs.

The EVF-2121S is a dual-12-inch full-range speaker that combines exceptional power handling with a wide frequency response. It utilizes a coaxial driver arrangement, providing even sound distribution and a cohesive audio experience. This model is ideal for medium to large venues, offering a robust SPL (sound pressure level) output and clear reproduction of vocals and instruments.

In contrast, the EVF-1121S features a single 12-inch driver, delivering precise, high-impact sound suitable for smaller spaces. Its design emphasizes clarity and detail, making it perfect for live sound applications. The compact and lightweight design also ensures ease of transport and installation, appealing to mobile sound reinforcement professionals.

The EVF-1181S is a dedicated subwoofer that amplifies low frequencies, featuring an 18-inch woofer for deep, powerful bass response. Its extended low-frequency output enhances the overall sound experience, making it an ideal choice for high-energy music events and professional club environments. Designed with rugged construction and efficient power handling, the EVF-1181S is built to withstand demanding conditions while delivering reliable performance.

The EVF-1151S combines a 15-inch woofer with an advanced high-frequency driver for a full-range sound that works well in theatres, concert halls, and corporate events. The speaker ensures clear mid and high frequencies, maintaining vocal intelligibility even in challenging acoustic environments.

Lastly, the EVF-2151D is a dual 15-inch subwoofer that enhances overall system performance with its ability to produce deep bass. Its compact enclosure design allows for seamless integration into various sound setups, ensuring it can meet the needs of both portable and installed sound systems.

All models in the EVF series incorporate advanced technologies, including proprietary transducers and custom-engineered waveguides, which contribute to their impressive performance. With features like durable enclosures and efficient power handling, these loudspeakers are engineered to provide reliable sound reinforcement for both live and recorded applications. Whether it’s a concert, event, or installation project, the Electro-Voice EVF series stands out for its versatility and audio excellence.
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