Brilliant new sound in the Bolshoi Theatre

Finally, after a six-year construction period, the Bolshoi Theatre in Moscow will reopen with a gala performance on October 28, 2011. This day, then, also the acousticians and media technicians of Müller-BBM in Planegg near Munich will have very good reasons to celebrate. Since 2005, acoustic specialists and planners have supported the most complex overall restoration and modernisation of this world-famous Russian cultural institution.

Müller-BBM is an international market leader in the field of acoustics for concert halls and opera houses. The company also has wide experience with the restoration of historic theatres. Its previous projects include major illustrious names such as the "Teatro La Fenice" in Venice or Europe’s oldest opera house "Teatro di San Carlo" in Naples. Certainly, with the Bolshoi Theatre, Project Manager Jürgen Reinhold had to face a very special challenge. The entire structure of the 150-year old building had to be stabilised. Parts of the building even had been in danger of collapsing. Except for the auditorium and the historic ballrooms, the historic building was almost entirely gutted, extended by six new underground levels and placed on an entirely new foundation. The auditorium was to shine once more in the former lustre of the 19th century – and listening to the orchestra, choirs and soloists would be as clear and brilliant as it was back then. The original sound of the Bolshoi had been lost throughout the centuries due to wear and tear, refurbishments and building alterations. Both objectives, the technical and constructional modernisation as well as the historic and acoustic reconstruction were very challenging for the acoustic design. "After working six years with high intensity it really was a wonderful moment to see the happy faces and the immense joy of the singers and musicians at the end of the first rehearsal", summarizes Jürgen Reinhold.

A close experience of music

In close cooperation with the restorers and with much attention to the historic example of architecture, the experts of Müller-BBM succeeded not only in recreating the once excellent acoustics of the auditorium – they could even improve it. The two most apparent acoustic measures are the now steeper rise of the stalls and the enlarged orchestra pit. The increased inclination of the floor in the stalls area creates a much better view to stage and improves the sound propagation. Size and depth of the new orchestra pit can be modified using modern stage machinery, allowing it to adapt to orchestras of different sizes for an optimum in acoustics. In addition, the so-called Cassa Acustica has been reinstalled under the pit’s wooden floor – recreating the historic design. Its semicylindric resonance body concentrates the orchestra sound, especially that of low-pitch instruments, as it did in former times. Also, the concrete floor slab under the stalls, which was installed in the 20th century, has been removed. A solely wooden construction now makes the acoustic experience even more intense as it is excited by the orchestra sound to perceivable vibrations.

Further acoustic optimisations are integrated into the gold-plated and refined surfaces of the auditorium. The sound of the orchestra and the singers’ voices are reflected by the wooden surfaces and thus provide the acoustic envelopment of the audience, while fabric curtains and seat cushions create the necessary sound absorption. All materials – from the wooden wall claddings to the upholstery of the auditorium seats – have been analyzed for their acoustic properties in the laboratories of Müller-BBM in Planegg near Munich. This allowed to determine the optimum materials for the hall. The interaction of all the selected materials defines the theatre’s acoustical character and contributes a lot to the original brilliance in sound.

Orchestra Manager Alexander Shanin is enthusiastic about the new acoustics. "Everybody has had doubts about how the auditorium would sound after the reconstruction. But when the orchestra first started to play after this long time, the sound was brilliant, clear and precise."

Beethoven to be honoured with a concert hall of his own

Below the theatre square, a new venue has been created – the Beethoven hall. Having its wooden floor built on height-adjustable podiums, this underground space can be transformed to be used for orchestra rehearsals, for chamber concerts or as a foyer for the historic theatre. To meet the diverse acoustic requirements, Müller-BBM developed a detailed and flexible acoustic concept. The height-adjustable podiums, mobile partition-walls and retractable curtains optimise volume and surface properties and thus adapt the acoustics of the venue to the relevant use.

Vibration control – good sound first

The concert hall's location below the theatre square and the now deeper foundation of the main building also brought one formerly unimportant, interfering sound source closer to the theatre: Moscow’s Metro. Two Metro lines in the theatre’s direct vicinity pass vibrations through the foundation into the building, where they become audible. Most affected is the new concert hall with its mere 40 m distance to the tunnels of the Samoskworezkaja line.

Based on numerous vibration measurements, carried out before and after the new foundation was set, Müller-BBM elaborated a number of acoustic measures, invisible to the audience, which protect against the vibrations of the Metro. Heavy walls with resilient mounting, special suspended ceilings and floating floor constructions protect the new concert hall and also the historic theatre against the vibration noise from the Metro. In November 2011 the last part of the control measures, a resilient mounting of the Metro tracks, will be executed.

Electro acoustics and media technology – high-tech inside a magnificent building

In the course of the restoration process, the building was not only equipped with modern stage technology but also with new, up-to-date audio and video technology. Centrally controlled, all productions, whether visual or acoustic, can be recorded and played back at the required location at the touch of a button. Apart from the main theatre hall, the system designed by Müller-BBM also supplies five additional, smaller historic halls, three ballet rehearsal stages, a large opera rehearsal stage above the theatre hall, which is also used for events, and the new underground Beethoven hall.

As complex the audio and video equipment may be, as user-friendly it is designed. On the central server, even the artists themselves might easily find and play music or video recordings for rehearsal purposes or for performances. Also here, all components for sound reinforcement and video projection are tuned for the theatre’s special architecture.

In total, 400 kilometres of cable runs have been designed and have been integrated into the theatre's architecture. Broadcasting corporations and television production companies from all over the world can now be connected without spoiling the theatre’s historic character with visible cables.

The next upcoming highlight for the experts of Müller-BBM will be the official opening of the "Parco della musica e della cultura", Florence’s new opera house with almost 2000 seats on December 21, 2011.