WSDG completes Mineirão Stadium audio makeover

Years ago, John Storyk established himself as one of the premiere acoustical designers, and throughout its four-decade history, the Walters-Storyk Design Group (WSDG) has been widely regarded as one of the top companies in its field.

The company has offices in South America (the Walters-Storyk Design Group/Brazil recently completed work on the renovation of the Mineirão Stadium), and it is currently working on two other major stadium renovations in that country. Built in 1965, the Mineirão Stadium seats over 62,000 people, and that many routinely watch soccer matches at the facility.

Forty-five years after its construction, Mineirão Stadium was ready for an upgrade to its audio and video components. On that front, WSDG designed the audio and video for the entire stadium, including all public areas. Pinning meters in the red was not the goal, according to Renato Cipriano, Partner/GM, Walters-Storyk Design Group/Brazil, who also answered several other questions with Broadcast Engineering.

BE: How long has WSDG had a presence in Brazil... does the company have a presence in any other Latin American countries?

RC: Thirteen years in Brazil, almost twenty years in Argentina.

BE: How active, if at all, is John Storyk in the company at this time?

RC: John Storyk remains a key component of a creative group, which has grown to over fifty full time acousticians, designers, project managers, systems integrators and related experts in WSDG offices in Argentina, Brazil, Switzerland, Spain, Mexico City, Miami, New York and San Francisco.

BE: Have the advancements in theatrical and home theater affected the expectations of fans regarding the audio component of large, outdoor arenas? How has WSDG responded to these changes?

RC: Although there is little direct relation between audio for theatrical and home theater environments, we see an evolution in these areas, including not only the technology behind the equipment, but also the acoustics of the spaces. New developments in both audio systems (loudspeaker systems, distribution systems and signal processing) and in testing/measurement technology are constantly raising the bar as to what the audience expects to hear.

This natural evolution extends to broadcast production facilities and large arenas. Standards for audio in arenas are still largely based on the security level for evacuation systems, which in terms of sound, reflects on high sound pressure levels (SPL) and Speech Intelligibility (STI) but only at the frequency range of the human voice, starting at around 150Hz and extending up to about 4kHz. We know that all arenas constantly display a huge amount of media content on their giant screens. Therefore, in all of our designs, including our recent stadium projects we make every effort to extend the full frequency range coverage of sound. It may seem obvious that this would improve the overall quality of the audio reproduction system without affecting the intelligibility of sound but in fact the opposite is true. As we increase the bandwidth of the system there is a natural increase in total SPL, which generally leads to lower STI values.

When you add that to the fact that large arenas have naturally high (local) reverberation times that are not only hard to deal with but are sometimes necessary to convey the crowd’s emotion (loudness) it becomes very tricky to make things work the way they are supposed to. Advanced prediction and analysis tools and careful analysis/calibration of installed systems have been playing a major role in this process. The more we employ them in such difficult environments, the better we get at it and the better the quality we can deliver to the fans.

BE: Do the differences in culture between North and South America affect, in any way, the work that goes into a huge project like the Mineirão Stadium installation?

RC: No doubt this affects our work and there are different areas where this becomes a real issue. The economic factor is one of the most critical issues. The ideal design solution does not often fit the established budget. Import taxes, especially in Brazil are way above average compared to the rest of the world and so, any imported equipment becomes a very expensive addition to the investment. In many cases, due to the size of construction projects in South America, these issues are not considered at the beginning of the project and can become an "extra" cost at the end.

Another important factor is manufacturer support which is usually a demand imposed early in the design process. Thanks to our improving economy, we are beginning to see this situation changing. Many large projects are being built in Brazil, and that has lead to an increased demand for better design earlier in the process. WSDG has been working in South America for about 20 years, we have watched this change closely and this recent increased demand has had a direct impact in our business, especially for large venues.

BE: Have there been any major technological advancements in the last decade or so that improve the quality of audio product that can be delivered to arenas that seat 60,000 people or more? If so, what are they?

RC: Significant advances on DSP controlled arrays with targeted directivity and audio over IP networks are the most significant changes in audio technology that affected the way we design for large spaces. However, I believe that the software we use for analysis and prediction, together with the measurement and listening exercises that we practice on all of our projects are still our most important tools.

BE: What are the “stipulated FIFA STI mandates,” and do they affect North and South America identically?

RC: Yes. The FIFA standards are universal. We hope to see some changes in the demands for STI, which is currently in the 0,5 range. This could lead to better sounding systems and consequently to improved acoustics, which lead to safer communication and a higher comfort level for the fans. This would be a challenge for large arenas and we would surely have fun with such task.

BE: What “sophisticated simulation programs” did you use to assess the reflections in Mineirão Stadium? Were these tools internally designed, or are they commercially available products? If software based, what platform do they run on?

RC: This was a particularly interesting moment in our design process. As mentioned earlier, we perform extensive listening, measurement and sampling tests in every project. In the case of the Mineirão Stadium, in the beginning of the design process, I went to the field, on a quiet day, empty arena, and during my precise observation/listening process I began to notice very distinct echoes bouncing off the inner concrete ring of the stadium. Later in the process, these observations were confirmed by the expert team in our European office, with virtual prototyping simulations done in CATT acoustics, a highly accurate, professional acoustical engineering software.

These findings led us to design custom acoustic treatments for the stadium’s upper ring, in order to achieve the desired STI values for the system. Again, had the STI demands been higher, we would have had to exercise even more acoustical measures to provide better quality for the audio system. This would have been challenging, but we enjoy the opportunity to apply our experience and tool set to resolving these issues.