Command Performance

Acoustics is the key to Pringle Richards Sharratt’s Shrewsbury music school, says Dean Hawkes.

The relationship of built form to structural logic holds a central place in the history and theory of architecture – from the preoccupations of Pugin and Viollet-le-Duc in the nineteenth century through to Kenneth Frampton’s recent book Studies in Tectonic Culture. It is perhaps curious therefore that the formal implications of the physical processes of the environment in buildings have received relatively little historical or theoretical attention. This may be because the analogue of environment and form is less immediately evident than that of structure and form. Nonetheless it is possible to establish a clear relationship between environment and form in all aspects of environmental performance. In the music school at Shrewsbury School, Pringle Richards Sharratt have done just this.

The first and most obvious environmental issue in a building for music is acoustics. This is the area of environmental design in which the explicit relation of form and performance has been longest established. There is also a substantial body of empirical and theoretical understanding of the acoustic performance of material and constructional details. All this has played a part in the Shrewsbury design.

The thermal aspects of building performance have not usually benefited from the same correlation with form. Recently however the growth of interest in ‘bioclimatic’ or passive approaches to heating, cooling and ventilation have begun the process that might be described as ‘form follows environmental function’. It is this school of thought to which this design-makes a useful contribution.

Since the end of the nineteenth century Shrewsbury School has occupied a site on the southern bank of the River Severn as it sweeps around the historic core of the town. The site is divided by its contours into two distinct territories, Upper Common and Lower Common. The music school is located between these at a point where the ground slopes steeply down to the west, close to a group of brick bul1dings, Tudor Court, and in the midst of a group of fine specimen trees.

Music plays an important part in the life of the school. The programme for the building was a direct reflection of the organisation and activity of the music department, which wanted spaces for practice, teaching and performance for music of all styles, from classical to rock. This led directly to the establishment of a clear hierarchy of room sizes: small for practice; larger for teaching; and a single large space for full orchestral rehearsals and, with retractable seating, for ensemble performance for an audience of 200.

The design is a lucid response to context and programme fused with the resolution of the acoustic and wider environmental questions. The location of the building provides the benefits of relative acoustic isolation from other functions that might affect it and, equally significantly, that might be affected by it. An inhabited elliptical brick base rises from the westward slope of the ground down from the plateau of Upper Common. This continues the brick of the nearby buildings into the landscape and offers the opportunity to place the main entrance at the upper level, with the rake of the auditorium aligned with the contours. The timber structure of the perimeter ring of practice and leaching rooms sits on top of the base, while above rises the cedar shingled roof of the central auditorium. The base is occupied by more teaching and practice rooms, including those for rock music that are thus acoustically separated from the gentler sounds of unamplified instruments.

The structural system follows the logic of the form. All internal walls are of dense blockwork; this is loadbearing where necessary and provides effective sound insulation between rooms. The external wall above the brick plinth is a ring of timber posts that support a glulam edge-beam. The posts are over-sized so they provide a barrier against external sound transmission between adjacent rooms. To improve acoustic separation, the support for the concrete ground slab of the principal floor is independent of the enclosure of the auditorium. The roofs of the perimeter block and the auditorium use the German Dickholz (‘thick timber’) panel system that provides both structural and acoustic performance. Over the auditorium they support the cupola that supplies natural and artificial lighting, natural ventilation and an element of acoustic control.

Axial symmetry is one of the fundamental parameters of auditorium acoustics. But some symmetrical geometrical figures must be avoided acoustically and the ellipse, with its focusing effects, is one. So the auditorium becomes an elongated octagon inscribed within the generating elliptical figure. The effect of this is to articulate the ring of circulation that divides the auditorium from the perimeter teaching and staff rooms, so that places are formed for occasional seats and built-in instrument storage. The dividing walls between the small rooms are ordered along the radii of the geometrical centres of the ellipse. The non-rectangular forms that result therefore avoid the acoustic problem of standing-wave interference.

The thermal design of the building is based on passive principles. The most difficult problem is posed by the auditorium and, to judge by a visit on one of the hottest days of the last month’s heatwave, the design is a clear success. Incoming air enters through the thermally massive brick undercroft and is supplied to the auditorium through acoustic attenuators.

Assisted by the height of the space, it is extracted through remotely controlled louvres in the cupola. Natural light flows down into the space from a continuous strip of glazing in the cupola, sufficient to illuminate the space for daytime teaching and performances – a nice reminder of the fact that all concert halls were daylit until the advent of electric lighting. In winter a dual system of warm air and underfloor heating provides heating.

In its rejection of the elaborate apparatus of ‘high technology’ this is, in the best sense of the term, a naïve building. In place of plant and machines it makes a form that expresses the physical processes of heat, light and sound as they flow, reflect and resound in architectural space. To this end, scientific abstraction has to be turned into concrete reality and this is, almost of necessity, an empirical process.

The music school has now been occupied for some months and is a demonstrable success with its users. But, perhaps not inappropriately, it is undergoing a period of fine-tuning. Experience has indicated where additional acoustic absorbers might go and which rooms should have window blinds. This is entirely in the spirit of the architects’ philosophy and provides the users with a sense of ownership of the building, through their direct participation in this process of refinement. Far better this than the remoteness of design code standards mechanically delivered.

Link: Architecture Today 

© Architecture Today 2001