Linear arrays. Features of sound reinforcement systems

Today, no major event can take place without modern equipment and sound reinforcement systems. Complex technical systems allow for good acoustics of the venue:

• They facilitate comfortable listening to music and speech, create the effect of presence
• They provide the highest possible sound pressure level of useful sound, conveyed to all listeners (clean, transparent sound in the correct dynamic and frequency range with sufficient volume)
• They prevent sound concentration and eliminate other acoustic defects

Sound and sound reinforcement research, the search for technologies and technically advanced systems that allow for the transmission of the purest, loudest and undistorted sound, led to the creation of linear arrays and served as a transition from spherical sound waves to cylindrical ones. And although line arrays as equipment for mass events have been used in professional acoustics relatively recently, it is already difficult to imagine constructing good quality sound at a large-scale event without them.

What is a line array?

This concept was first introduced in 1957 by Harry Olson, who was convinced of the undeniable advantages of line arrays in transmitting sound over long distances. In acoustics, a line array is a group of non-directional radiating elements arranged in a straight line, closely located and operating in phase with the same amplitude. A line array is highly directive over a wide frequency range, it excites the reverberation field much less and noise is reduced in space. That is, simply put, line array systems can distribute sound over long distances with a low level of distortion. For example, at a distance of 16 meters from a point source of 110 dB, the sound power will be 86 dB, and a line array shows figures of 98 dB under equal conditions.

How Line Arrays Work

Line arrays work by combining sound waves from a large number of closely spaced sound sources in a coordinated and orderly fashion. Line arrays build sound based on constructive and destructive interference. The main property of line arrays is to provide high directivity in the vertical plane, which works equally well for a vertical row of omnidirectional emitters and for the horizontal plane of the array (unlike a single emitter).

The behavior of line sources and the sound directivity patterns have been predicted by mathematical models for over 70 years. And in recent years, using computer modeling that sums up the complex values ​​of sound pressure from all emitters, it is possible to predict the frequency response of the system at a specific point in space.

Why are line arrays becoming more popular?

• Predicted result. Instead of an uncontrollable spherical wave, a line array can be used to obtain an easily controlled and predictable sound wave source
• A smaller drop and a more uniform distribution of sound pressure over long distances of the concert venue. That is, loud, clear, high-quality sound

Main types of line arrays

• Compact low-power line arrays. Most often, they are a vertically elongated case with loudspeakers mounted in front with an embedded digital processor. Each loudspeaker is adjusted by a multi-channel amplifier
• Concert line arrays consisting of at least 4 vertical columns of acoustic systems. The sound field is adjusted by giving the line array a curvature in the vertical plane