You can forget everything you know about sound installations with a clear conscience. An acoustic engineer from the renowned Wroclaw University of Technology and a sound engineer from the equally reputed audio company M.Ostrowski are breaking new ground with the installation of a new PA system in the Wroclaw opera house: a system that has about as much in common with conventional PA systems as the Starship Enterprise has with the first flying machines.
The history of a great opera house
Let's start right at the beginning. The "Opera Wroclawska", one of the best known, most famous and also the largest opera house in Poland, was designed by the famous architect Carl Ferdinand Langhans and built between 1831 and 1841. The fates, however, did not initially smile too kindly on the neoclassical building. It was burnt to the ground by a devastating fire in 1865, only 24 years after the building was completed. By 1867 it had been carefully rebuilt according to the original plans, but the celebrations were short-lived: the building was destroyed again by another fire in 1871. It again took just over a year before the show could go on.
The theatre was at least spared from the flames during two world wars, the Nazi terror and communism. In the end, however, plundering and time took its toll on the building and in 1997 it was decided that this icon on the smart Swidnicka shopping street in the Lower Silesian metropolis (pop. 600,000) should be completely redeveloped and restored to its former glory.
Science and technology: top specialists in the country lend a hand
The opera house had to remain empty for eight long years, a huge challenge for director Ewa Michnik, while the country's top specialists left hardly a brick in place. Two of these highly-qualified specialists are Dr. Piotr Kozlowski, an acoustic engineer and system designer from the Wroclaw University of Technology, and Wojciech Grzadziel, a former student of his who is now sound engineer and head of the Audio Team at M.Ostrowski, the company whose impressive concept won the contract to install the opera house sound system.
The task in hand was considerable: A large, digital 5.1 audio system of the highest quality for the entire signal path with a very natural sound was required – audible but not visible to the audience. So it needed to be discreet – with the sub-bass directed at the audience if possible so that neither the musicians in the orchestra pit nor the performers on stage would be disturbed by the deep, energy-rich frequencies. Of course, it also needed to be able to supply radio and television with all the signals in their purest form – fresh and untainted – from the microphone inputs. EUR 1,000,000 was approved for the audio system by the investor, the Lower Silesian Government.
The technology in detail
Dr. Piotr Kozlowski was aware that he had to perform the almost technically impossible. But as a scientist he knew how to tackle the problem. He knew, for example, that the entire signal path could only be made up of the highest quality devices, as a chain is only as strong as its weakest link. For this reason, the head of renowned acoustic company Pracownia Akustyczna opted to install 12 top quality Yamaha AD8HR microphone preamps/DA converters, which can be remotely controlled from the control room. The devices digitally split the signals to provide the monitoring and FOH consoles with two identical packets, each with 96 microphone channels. All the channels - had been splitted in the analog domain just before they've reached the preamps (this happens before the DA conversion inside the AD8HRs) to feed any outside broadcast van that may be necessary.
Two cascaded Yamaha DM2000 mixing desks for the audience mix are located in the gallery control room. These receive the microphone channels and various media players. A third DM2000 is available on the stage as a monitor desk for large productions. For less extravagant events, stage monitoring is provided from the FOH consoles in the control room. The monitors in the control room consist of a ITU-5.1 circuit with five Yamaha MSP10 studio monitors and a Yamaha SW10 subwoofer.
Pure luxury: two Yamaha DME64Ns for FOH and monitoring
At the core of the system, two fully-configured Yamaha DME64N are dedicated to routing and loudspeaker signal processing, one for FOH and one for the monitors. The devices are located opposite the control room, approx. 40 meters away at an angle on the fourth balcony. The DSP engines have (like the Yamaha consoles) MY16-AE cards in the slots that provide a fully digital interface to the outside world in AES/EBU format. On the output side, the FOH-DME is also equipped with two MY16-C-CobraNet cards that allow the CobraNet-compatible FOH loudspeakers from the US company Renkus-Heinz to be digitally not controlled but fed with digital audio (4 x LFE, 3 x Center and 8x L/R). The rack also holds five Yamaha DA824 converters, which transmit the available signals in AES/EBU format for the stage monitors, the surround sound loudspeakers and other systems ("Voice of God" on the ceiling, in the foyer, etc.) in analog format to amps (incl. three XM6150, one P7000, two XM4220).
Networking is everything, even when you're in a circle…
But how do the signals travel the long distances in the opera house to their destinations? The answer to this question is an ultra-modern Optocore network, which connects the three main areas: stage, control room and rack room to each other. The AES/EBU signals coming from the AD8HRs are received by the Optocore interfaces (four DD32/one DD32E) in the stage rack and transmitted via two fibre-optic cables (one for redundant signal routing - redundancy ≈ backup). Optocore interfaces are also to be found in the destination (rack and control room). The signals from the circular Optocore network (AES/EBU format again) can be extracted from the interfaces for processing before they are transmitted across the network again or returned. Up to 512 digital channels can be transmitted across this fibre-optic ring – a figure that leaves plenty of headroom for even the most complex application.
Dr. Piotr Kozlowski and Wojciech Grzadziel on their installations
"The investor's requirements for the installation were very demanding, so we had to come up with quite a few ideas", explained Dr. Piotr Kozlowski from Pracownia Akustyczna. But neither the acoustic specialist and system designer or his partner from M.Ostrowski, Wojciech Grzadziel, were put off by the challenging objectives. "Being able to use the best equipment on the market was a huge help in achieving these goals. The Yamaha preamps and consoles, the DME64Ns and the Renkus-Heinz loudspeaker systems are, without a shadow of a doubt, fantastic – the sound is very natural and detailed. They also have numerous varied and flexible connection options to enable a fully digital system to be created – perfect for our needs", says Dr. Piotr Kozlowski.
"Ground loops and costly system maintenance are a thing of the past here", adds Wojciech Grzadziel from M.Ostrowski. However, the wordclock synchronisation proved to be a real challenge: "After all, we have countless different digital formats here, all of which have to be synchronised to the same wordclock. In fact at first there were digital clicks in the signal path, but we managed to get rid of them by changing the settings of the Optocore interfaces. The difficulty lay in actually finding the cause of the problem."
How do you make a huge PA system simply (or not so simply) disappear?
Another ambitious task was to make the entire system practically invisible. "We needed to hang a curtain in front of the LCR loudspeakers – and I spent ages trying to find a material that would barely affect the sound", explains Dr. Piotr Kozlowski. Five inconspicuously positioned loudspeakers, partially painted in the same colour as the wall, were positioned level with the audience so that visitors would perceive the sound to be coming from stage level.
"The directivity of the LFE bass required by the investor was achieved by specially programming the DME. On the stage and in the orchestra pit we can reduce the sound pressure by 7 dB at sub-bass frequencies compared with the level in the auditorium. Bass often poses a problem here. But with the extremely flexible programming of the Yamaha DMEs anything is possible, which is why we always use these devices in all of our installations - without exception. They allow us to easily implement our basic principle of giving each loudspeaker its own optimised signal – with no compromises!" adds the University assistant professor.
Programming of the DME itself was carried out by Wojciech Grzadziel, and the head of the Audio Division at M.Ostrowski knows this job inside out: "I've configured just about every single DME sold in Poland. They're usually FOH PA systems – and I almost always have the configuration in my head before I begin. We tried other signal processors, but the DMEs deliver the most predictable results. Also, the many different connection options, analog, digital, ADAT, AES/EBU, are a huge help – never mind the completely user-configurable DSP modules, effects, dynamics, etc.". But according to Wojciech, the most important things are that the DMEs work perfectly, they simply do not crash.
Fig. 8: The team: Dr. Piotr Kozlowski from Pracownia Akustyczna and Wojciech Grzadziel from M.Ostrowski leaning against a Yamaha DM2000.
Combined know-how for an unprecedented modern system
The way Dr. Piotr Kozlowski from Pracownia Akustyczna and Wojciech Grzadziel of M.Ostrowski have combined their skills and knowledge during the installation of this system has been impressive. With their experience and feel for outstanding equipment they have created an audio system that sets new standards in Europe. In this renowned cultural city, despite all the science, theory, practical experience, precision and refined tastes, hard manual labour is also involved. Loudspeakers with a combined weight of more than a tonne are concealed at a dizzying height behind the famous red curtain. "You'd be forgiven for being nervous", remembers Dr. Piotr Kozlowski with a smile. However, he can't hide the fact that he enjoys a good challenge.
Company profile:
M.Ostrowski, with its headquarters in Wroclaw (Breslau), Poland, was founded in 1990 and sells musical instruments and professional audio equipment. Their range of products covers everything that has anything to do with music. As the company has grown rapidly, so too has the variety of the products it sells. To keep up with the increasing demands of its customers, the company started to work closely with numerous foreign manufacturers.
In 1999 the Acoustic Design Division was set up. With highly qualified employees, specialist software and in-depth knowledge of modern technologies, M.Ostrowski provides top-quality services.
The company's biggest asset is its staff; their comprehensive technical knowledge and wealth of experience has secured the company its place in a highly competitive market. To maintain its competitive edge, the company regularly sends its specialists to workshops and seminars run by foreign partners. This ensures their level of knowledge is always current and enables M.Ostrowski to implement the most modern solutions in the acoustic design field and in the installation of the latest audio systems.
Pracownia Akustyczna
The specialists at the renowned audio organisation Pracownia Akustyczna, based in Wroclaw (Breslau), Poland, have 10 years experience in the audio field and have made a name for themselves across Poland since the company was set up in 2004 (by Dr. Piotr Z. - Kozlowski). The group, called “The acoustic laboratory” in English, works on event projects at every stage of their development. In other words, their work includes everything from basic concept through design and implementation to final tuning. They also provide high-quality live mixes, the second key skill of this Polish company.
Their impressive references cover numerous projects, such as outside broadcast vans, small recording studios, large concert halls, live studios and even enormous sport stadiums or famous opera houses. Their work deals with all aspects of the project that may have an effect on the acoustic result. This even includes the design and implementation of structural (e.g. for spatial acoustics, sound proofing) and electroacoustic measures. Sound level measurement, computer simulations and meticulous final tuning of room acoustics are routine for Pracownia Akustyczna. Another highlight is their collaboration with other engineers and designers from various disciplines in the construction of, for example, ventilation systems or entire buildings with regard to acoustics and acoustic emissions.
The Group's employees are all high-calibre scientists, many of whom have doctorates. However, they all have plenty of practical sound engineering experience. They are able to assess precisely what the customer really needs. Completely satisfied investors are the most important objective – and perhaps the best reward for the committed Pracownia Akustyczna team.
e - mail: pracownia@akustyczna.pl
