Intelligent audio design

Digital technology allows events organisers to hear how sound will behave in a venue long before it is built

Specifying and designing an audio system for a stadium – or any large venue – is one of the most demanding tasks that can be undertaken by a professional audio system engineer. So many requirements – often conflicting – are set out at the initial briefing stage that it is a wonder that the design ever gets completed. However, audio designers are a determined breed and most will stop at nothing to produce a result that will excite and energise the crowds.

Speakers positioned on the Olympic Stadium
in Sydney in Games mode

So what are these requirements? Well, first and foremost, the system must be suitable for the particular environment that it finds itself in – particularly if it is an outdoor stadium with all the potential weather hazards and changes in climate that could affect the loudspeakers. The sound must be clearly audible, whether it is being used as a pubic address (PA) system, or as an entertainment system.

In a large stadium or indoor arena this means specifying the correct loudspeaker in terms of quality and throw, getting the design of loudspeaker layouts correct and creating signal path delays to deliver even sound coverage. The system must be right for a multitude of uses. It must come in at the right price, to meet budgetary requirements. It has to be correctly installed to meet health & safety requirements. And these days it must also be future-proof: a system must be capable of being networked, line monitored and compatible with the control devices of the future.

This last requirement is becoming increasingly important, particularly where a stadium is built for a specific event that will last only a short period of time. Every element of the installation needs to be reusable – either on site or elsewhere. Consideration has to be made for the future use of the venue: will it become smaller after a major event, will it be moved, or will its use change?

Addressing these questions at the outset can save time and money at a later date. From the outset, the designer has to take into account the type of loudspeaker dispersion, its size, its weight and its ability to be re-configured for another venue after the event. The only elements that have to be written off and considered redundant are cables, specialised brackets and labour costs.

There are many different software packages available for audio system designers, including the Bose proprietary Modeler software used in designing audio solutions for Olympic venues in Sydney, Athens and Beijing, as well as Euro 2004 in Portugal. Most recently in the UK, the Premiership football club Portsmouth FC’s stadium at Fratton Park was designed by Bose engineers using both Modeler and Auditioner.

Sydney’s experience
In Sydney, 23 of the Olympic venues used Bose loudspeaker systems to support everything from music to public address announcements. Careful design ensured that each spectator, athlete and official could understand every announcement, ensuring that events ran smoothly and the experience was truly special. As part of the bidding process, the engineering drawings of each venue, information about materials used in construction, and crowd fluctuation scenarios were fed into the Modeler software program. This enabled the team to select appropriate loudspeakers, create effective cluster configurations, and determine the optimum positioning.

The unique Bose Auditioner system was then used to demonstrate how the sound system would perform, a long time before the Olympic Stadium’s completion. Having the ability to actually audibly demonstrate to the representatives of the organising committee of the Olympic Games gave them something tangible to assess the proposal by. This unique tool enables designers and their clients to actually hear the difference in how the sounds in a stadium will differ when full of people as compared to when half full. The design engineer then compensates for the variances by setting a number of equalisation settings within the digital sound processor; these settings can then be instantly recalled by the sound engineer for each event.

Sound control
Control of the audio is another vital consideration during system specification. There are many different controllers available, and most these days use digital signal processing. These add much greater flexibility, increased reliability and are easier for the end user to operate than older analogue systems. However, the real value lies in the complex system set-up, undertaken by a skilled engineer and reliant on a very specific brief.

By configuring the hardware to match the job, a good control system can add power, sophistication, flexibility and future-proofing to almost any loudspeaker system. So if an indoor sports venue is in “match” mode during the day, it can be switched to “dance” mode at night and the correct sound level and inputs/outputs are delivered at the literal flick of a switch. Stadium sound can be configured for large or small crowds, and a PA message can be delivered to individual zones or to the whole venue, making crowd control easier to manage – this is where the safety factor benefit really assists stadium managers and their customers alike. The Bose ControlSpace ESP-88 processor is just one of the systems available to bring real power to engineered sound in large venues. The associated control centres and zone controllers are easy to use for non-technical personnel.

Sound can do so much more than merely deliver a message. It can help to create an atmosphere of excitement and anticipation. Imagine sitting in a stadium where everyone is quiet and there is no amplified sound. The mood is very subdued. Then picture being in a stadium where the sound is of poor quality; you can’t hear the announcements, the sound reaches you in a series of echoes, and the music is too loud or fuzzy or crackly – this is just annoying.

Now steer your thoughts towards a stadium where the announcements are as clear as a bell wherever you are sitting. The music is exceptional and at just the right level and everyone around you feels comfortable, excited and happy. Enthusiasm is catching, isn’t it? Creating a wow factor and making the whole event memorable; this is what quality sound can do for even the largest event.

This article was contributed by Bose Limited