RE/P Files: Concert Sound Reinforcement Approaches Maturity

House Mix Position

The increasing use of linear systems has powerful implications for concert sound engineers. Just as Compact Discs highlight the sonic differences between various recordings, so linear reinforcement systems tend to strikingly reveal the differences among various mixing styles.

For this reason, the responsibility for subjective sound quality is shifting away from the loudspeakers and toward the input signal, where it rightly belongs. Many live performance mixing engineers are still learning to adjust to this concept.

As concert sound systems continue to improve, however, attitudes will change. Once we fully accept the concept of linear sound reproduction, we open ourselves to dramatically broader creative possibilities.

In order to fully exploit the capabilities offered by improved systems, concert sound engineers will inevitably make increasing use of the same tools used in studio recording. The sonic differences among various limiters and equalizers, for example, will assume greater importance; in fact, outboard processing in general will play an ever-widening role in concert sound, and mixes will become more and more complex.

The Prism, developed and built by Showco. Shown here is a full Prism rig for a recent Genesis concert at the Reunion Arena, Dallas.

Ultimately, the goal will not be to simply equal the sonic complexity and clarity of studio recordings, but to provide the audience wish a sonic experience that surpasses that of recorded music in scale, dramatic impact and immediacy.

Obviously, all of this will make the mix engineer’s job more demanding, because he or she will still have to contend with the inevitable pressures of live production.

Recording engineers at least have the luxury of taking their time, reconsidering and fine tuning a track or final mix. In live sound, however, there are no retakes. Consequently, concert reinforcement engineers will need to be able to pre-plan their use of effects to some extent, while retaining the flexibility that concert work requires.

Therein lies one of the greatest potential benefits of current advances in sound system testing and equalization. Coupled with in-concert measurement (using the program as source material), complementary equalization assures an unprecedented degree of consistency in sound system behavior.

Because the technique acts to linearize the entire loudspeaker/room system, it effectively erases the local acoustics to a controllable extent, and even permits imposition of an “ideal” (arbitrary) acoustic signature in its place. Given that one can thus idealize the acoustics of even the most reverberant venue, it becomes possible to standardize processing and console settings, to the extent that very sophisticated mixes are practical.

In all likelihood, we will see snapshot-style console automation come to be used in concert reinforcement in the foreseeable future (dependent upon the music’s stylistic requirements). Add the potential for MIDI-based automation of signal processor parameters – synchronized with the console automation system – and the creative possibilities become truly staggering.

Concert engineers who keep themselves abreast of these developments, and help to demonstrate effective use, face a bright future.

The Future of Concert Sound

With developments of the past decade, the current generation of sound reinforcement technology is nearing its maturity. Further improvements will only be made through radically new design approaches, requiring major changes in the way that sound systems are operated.

To understand why this is the case, consider the difference between a studio monitoring system and a concert PA.

The studio monitor works in a relatively controlled environment. Any open mics are acoustically isolated from the monitors, and the characteristics of the control room are essentially stable. In such an environment, it is relatively easy to assure that the monitor system is consistently linear.

Therefore, the recording or production engineer has a high degree of control, and the results are predictable and repeatable. By contrast, a concert PA is a complex and dynamic system. The acoustics of the space are affected by temperature, humidity and audience size, and are thus in a constant state of flux.

Open microphones abound, and their signals are routed in a number of ways to loudspeaker systems located both in the house and onstage. Because the positions of some microphones inevitably change in the course of the show, their acoustical relationships to the loudspeakers vary.

Finally, gain, equalization and signal processing changes are made continually, at many points in the system, by several different operators.