Concert Hall Acoustic
The Concert Hall primarily serves as a music theatre (complete with orchestra pit) and as the Vienna Boys’ Choir’s own concert hall; but – as can be seen from its schedule – it also hosts other types of productions, such as Rock Opera, Children’s Opera, and events staged by schools and children’s groups.
Quiring Consultants, from Aldrans near Innsbruck, were responsible for designing the room acoustic. Their brief included taking electroacoustic factors into account. Quiring had previously undertaken major commissions in the arts world, including projects such as the new halls in Musikverein Wien, the Museum Quarter, the entire campus of the Vienna Musical University, and the new Festival Hall in Erl.
From a spatial acoustics perspective, the Concert Hall constitutes a chamber opera or chamber music hall, in terms of both its use and its size (an audience capacity of 400).
In plan view the hall follows a classic concert hall design: the side walls are arranged like overlapping scales, and their structure causes sounds from the stage and the orchestra pit to be reflected back to the audience rapidly. The effect is one of being surrounded by music, creating a sense of both intimacy and spaciousness. The acoustician ensured that construction and fit-out – including the various material densities used – achieved the effects desired across a broad bandwidth.
Other notable features include an apron curtain and an orchestra shell by the side of the stage, designed to improve communication between players and provide optimal sound projection into the Hall.
The Concert Hall was originally intended to be both wider and deeper. To conserve the gatehouse/ servant’s quarters at the Augartenspitz, the Concert Hall had to be somewhat truncated on its left side (when viewed from the rear). However, in practical terms this had no real impact on the room acoustic design.
To balance the hall’s acoustic, it was also important to have the ceiling high enough to achieve the required room volume. Expanded metal mesh is used to conceal the ceiling visually, but acoustically the ceiling forms a fully integrated part of the hall.
The textures used in the seating were designed so that the difference between an empty seat and an occupied seat, in acoustic terms, is extremely small. These seats replicate the acoustic characteristics of the human body almost perfectly.
Room acoustic and projection
The sound system is attuned to the Concert Hall; here, the sounds of voices and instruments can reach the audience by purely acoustic means. This therefore demands a disciplined approach to electronic amplification, to ensure that nothing works against the Hall’s natural acoustic. The surfaces which form the Hall’s boundaries are designed to allow for the use of electroacoustic equipment – and most of all to avoid strong feedback.
The Hall has no parallel planes, as these could create flutter echoes. The back wall of the Hall and the front of the balcony are designed to avoid creating any unfavourable sound reflections.
When it came to carrying out preliminary testing on the acoustic design, Dr Quiring, who served as both room acoustician and contractor for this project, did not take any short cuts. He constructed a 1:10 scale model of the Concert Hall, in order to gather data which would be useful during construction, and to take detailed measurements forward when actually shaping the Hall.
Acoustic: Quiring Consultants