PHILHARMONIC ACOUSTICS 

Harold Marshall Marshall Day Acoustics LTD
P O Box 5811 Wellesley St.
1000 Auckland, New Zealan
harold.marshall@marshallday.co.nz

Joanne O. Valentine
Marshall Day Acoustics LTD
P O Box 5811 Wellesley St.
1000 Auckland, New Zealand
joanne.valentine@marshallday.co.nz

Thomas Scelo
Marshall Day Acoustics LTD
P O Box 5811, Wellesley St.
1000 Auckland, New Zealand
thomas.scelo@marshallday.co.nz

Popular version of paper 1pAAb4
"Acoustical considerations in the design for 'La Philharmonie de Paris'"

The 2006 competition for “La Philharmonie de Paris” included what is arguably the most comprehensive acoustical design instructions ever provided in such a context. The “programme acoustique” was supported by a general requirement that the design should be a “new typology” and specifically that the recognized “types” of concert hall (shoebox, vineyard terrace, fan) were unacceptable.

Of course no design ever takes place in a vacuum – at the very least there are the first principles that define both the characteristics of the concert experience and the architectural and acoustical dimensions that enhance it. The preferred acoustical conditions have been painstakingly established over a century of research, while the architectural possibilities have been demonstrated in an astonishing variety of concert spaces during the past 5 decades.

The acoustical brief for the Paris competition was very specific. The room was to sustain multiple (musical) uses in an environment both reverberant and clear, and with a high lateral energy fraction. That is, “clarity with an ample reverberation“. For most of the last century the conventional wisdom decreed that these objectives were mutually exclusive. Where they had been attempted together, compromised performance for all functions usually resulted.

There were two groups of concert halls which contradicted the conventional view. In a first attempt to provide early lateral reflected sound in a non-rectangular hall some 40 years ago, the principal reflectors in the Christchurch Town Hall (2750 seats) were separated from the reverberant boundaries of the space which contained them. (In conventional halls the same surfaces provide both the early reflected sound and the reverberant boundary.) That hall and its successors, the Michael Fowler Centre in Wellington, Segerstrom Hall in Southern California, and the Hong Kong Cultural Centre, firmly establish this approach as one way to fulfill the programme acoustique. The interior surfaces in such halls are placed to provide each listener with the desired early reflections while the reverberant boundary defines the space within which the reverberation can develop. (The “reverberation time” is directly proportional to the room volume.) The designer is thus freed from the constraints of size and geometry.

The second groups of halls is much more recent. These are basically small rectangular halls (never more than 1900 seats) with operable wall surfaces opening into auxiliary reverberation chambers which are a significant fraction of the total volume. (1/4 to 1/2) Adjusting the opening area allows control of the total reverberant volume and audibility of the reverberation. The most imminent example of this approach is the Lucerne Concert Hall. The control between the volumes is more direct in this case, but the size and form limitations constrain the design.

The solution proposed for Paris

The acoustical/architectural solution proposed is found in two nested chambers – an inner space producing visual and acoustical intimacy between audience and performer for all of the programmed functions and an outer space with its own architectural and acoustical presence. The acoustical interaction zone shared between them gives the possibility for the full range of acoustical adaptability required in the acoustical programme. The audience enters the hall through this in-between realm, beautifully realized by the architects in the form they have given to the acoustical idea. It is the architectural realization of the anticipation of a concert during orchestral tuning.

The material included in this presentation is limited to the competition phase of the project. The rigorous testing of these concepts in both computer and physical models is proceeding.