Müller-BBM masters acoustic challenges in the new opera hall in Florence

As the culmination of Italy’s 150th anniversary celebrations, the inauguration ceremonies of the Nuovo Teatro dell’ Opera di Firenze are planned, which will start on 21st December. In the modern event centre, a new opera hall will be inaugurated by world-class musicians. In order to achieve a brilliant sound experience in the avant-garde auditorium, the acousticians of the company Müller-BBM demonstrated all their skills.

At present the location, which is situated a bit outside of the historical city of Florence and which is to establish itself as a new Italian musical and cultural centre, still seems to be a construction site. However, the hall which will primarily serve as an opera hall with 1,800 seats has been completed and offers the best acoustic conditions required for its use. Here, the architect Paolo Desideri presented Munich’s acousticians with a special challenge: "The architects have chosen a very modern interpretation of the historical gallery theatre with a horseshoe shape", the acoustician Jürgen Reinhold describes the situation of the Florence opera hall challenging him and his colleagues from the international engineering company Müller-BBM GmbH based in Planegg. "This form of the hall has had a decisive influence on our acoustic design."

As elegant as the opera hall appears to be with its seemingly elliptical shape, as narrow is the leeway which this geometric design gave the acousticians. However, Reinhold and his colleagues found a smart solution: "One characteristic of the auditorium is that its visually perceived form does not correspond to the acoustically effective space", explains Jürgen Reinhold. "We have planned an acoustically completely transparent fine metal mesh inside the hall. This mesh conceals the traditional rectangular shape enclosing the room." Behind the mesh, acoustically effective elements and surface structures are hidden from the audience’s view. These are, for example, diffusers for scattering sound of medium and high frequencies, or horizontal lamellae which together with the vertical walls direct sound reflections to the audience. The curvatures of the hall are optically preserved, but the sound behaves like in the traditional rectangular shape of a concert hall.

Jürgen Reinhold, who has also helped the Bolshoi Theatre in Moscow and the Teatro "La Fenice" in Venice to regain their famous brilliance of sound, also favoured the resonant material wood: "We have taken up a construction method used in opera houses from the 18th and 19th centuries, which has fallen into oblivion in the past decades", Jürgen Reinhold explains. "All audience seats are supported by a pure wood construction. The wooden girders are covered by a spruce board with a thickness of 45 millimetres, which, in turn, supports the oak parquet."

The new Parco della Musica e della Cultura, which is the official name of the culture complex, will be the new home of the Maggio Musicale Fiorentino and will provide space for 5,000 guests in three venues which can be used simultaneously: the opera hall - called Teatro dell’Opera - with 1,800 seats, the concert hall with 1,000 seats and the so-called "Cavea", an open-air auditorium on the roof for an audience of 2,200. Another task for the acousticians: "To allow for simultaneous performances and rehearsals in the three areas, it is essential to ensure an optimal acoustic separation", says Jürgen Reinhold. The sound insulation between the opera and concert hall could only be achieved by separating the two areas as far as possible and by installing an acoustic joint between the two buildings.

The engineers have also provided for a possible wider use of the opera hall. For example, curtains are hidden in cavities, which can be dropped behind the metal mesh, if required. This leads to a reduction in the reverberation time and enables rock and pop music performances. However, tomorrow’s inauguration will be classic: Zubin Mehta conducts Beethoven’s Leonore Overture in a very modern setting - with acoustics committed to the highest musical standards.