This page contains a Flash digital edition of a book.
INTERVIEW 027


The purpose built labs are all floated rooms, with acoustic treatment, a large projector and screen, client facilities and use an Ambisonics surround-sound system to replay calibrated simulations using 12 Dynaudio BM5 speakers running off six Quad power amps.


“A shoebox hall is a very good thing because it’s not too wide. A potential problem with the design is when a venue gets to about 2,000 seats and you have to keep it narrow, people can end up too far away from the stage.”


Sugden, led Rob back to design for the performing arts. The first major project for the practice that was a huge project, even by today’s standards, was the Hong Kong Shanghai Bank HQ, which was well under way when Rob started. The team in Hong Kong was Arup’s first dedicated acoustics team to be established outside the UK. He comments: “Our work on the Hong Kong Bank building in 1985 helped launch Arup Acoustics’ presence in Hong Kong and worldwide.” Rob’s first major role as principal acoustician was Bridgewater Hall, Manchester, in 1989. The 2,400-seat home of the Hallé Orchestra in Manchester, widely acknowledged as one of the best concert halls for acoustics in the UK. It is also one of several that Arup Acoustics has isolated from the ground borne noise of adjacent rail tracks or roads. At Bridgewater, the 22,500 ton structure has no rigid connection to its surroundings; instead it is supported on a matrix of steel springs. The undercroft beneath the hall has also become a popular filming location. Most concert hall designs fall into one of two forms. Traditional shoebox-shaped concert halls have their design roots in the 18th and 19th Century rectangular court ballroom form in which the classical orchestral concert was born. The prototypical shoebox room is tall, narrow, with parallel side walls, and most of the audience is formally arrayed in front of the orchestra, such as Musikvereinssaal Vienna, Birmingham Symphony Hall, or Kilden concert hall Kristiansand, a design by Arup Acoustics. Acoustically the reason for the shoebox design is that when listening to music it is important for an audience to hear sound that arrives quite soon after the direct sound to give clarity and intimacy. For orchestral music it is also very important that the sound comes from the sides. So the building needs to have surfaces to the sides which aren’t too far away from where the audience. Rob explains: “A shoebox hall is a very good thing because it’s not too wide. A potential problem with the design is when a venue gets to about 2,000 seats and you have to keep it narrow people can end up too far away from the stage. Birmingham Symphony Hall is a good hall but a few hundred people are stuck away towards the back.” The other form of design is the vineyard. These are, for the most part, a 20th Century development, following an arena concept that wraps the audience around the performers. The result is that the audience is seated closer to the performers, in a less hierarchal arrangement than found in the shoebox model. These rooms are typically wide, with audiences organised in terraces around the orchestra, and whose wall surfaces provide critical early reflections of acoustic energy. The Berlin Philharmonie, St. David’s Hall Cardiff, and Suntory Hall Tokyo are examples. The auditorium is divided into sections with walls created between the sections. They in a sense make up for not having a narrow hall.


At Bridgewater Hall, Rob tried to find a hybrid solution, somewhere between the shoebox and the vineyard. That was a fairly bold thing to do. With a concert hall you only get one go at it. So the prototype is the final thing. Rob adds: “Working with the architects we developed a hybrid design which we think works really well. It has good acoustics and a sense of space as a hall. I feel very much that to get a great auditorium you have got to have this balance between acoustics, architecture and what you might call theatricality and functionality as well as safety and technical systems. If any one of those is too strong you have an imbalance. I could take you to a hall that looks good and sounds terrible or I could take you to ones that sound good and look terrible. There is always a balance to be struck.” Bridgewater Hall was one of the first projects to use computer modelling for acoustics, using a programme called Odeon, which they still use today. The software tool is used for room acoustic design to predict the acoustic quality of interior spaces. For an acoustician the most efficient way to start a design process is to have the architect’s 3D model and import it into the software. They are then in the position of using it to inform either the ground up creation of a building space or putting in sound systems in existing building spaces. At later stages analysis is made to select the final layout of surfaces, choice of material properties and loudspeakers to obtain the optimal spatial coverage and the optimal values for acoustical parameters such as reverberation time (RT), clarity and the Speech Transmission Index (STI) used to measure speech intelligibility. For reverberation time Rob says what he is aiming for. “The longest times you want are for things like choral and organ music. You might want a mid frequency RT time of about 2.5 seconds. For symphonic concerts two seconds, for opera somewhere between 1.5 and 1.9 seconds, for recitals 1.2 to 1.8 depending on the size of the hall. Then going right down for drama you want one second and for conferences 0.8. And ideally for a speech based recording studio you don’t want anything at all. Maybe 0.5 seconds.” Steering sound in particular directions and pinpointing targeted areas and zones are all important factors for consideration when discussing architectural audio. Subtlety and accuracy are key. But it is the ability to disguise audio technology, and be flexible, whilst still satisfying the aural requirements of a space that Rob feels, demands a great deal of time and attention.


AURALISATION A major part of Arup Acoustics current practice is their pioneering use of auralisation (the sound equivalent of visualisation) as a design and demonstration tool. Arup’s SoundLabs in New York, London, Glasgow, Melbourne and Hong


www.mondodr.com


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62  |  Page 63  |  Page 64  |  Page 65  |  Page 66  |  Page 67  |  Page 68  |  Page 69  |  Page 70  |  Page 71  |  Page 72  |  Page 73  |  Page 74  |  Page 75  |  Page 76  |  Page 77  |  Page 78  |  Page 79  |  Page 80  |  Page 81  |  Page 82  |  Page 83  |  Page 84  |  Page 85  |  Page 86  |  Page 87  |  Page 88  |  Page 89  |  Page 90  |  Page 91  |  Page 92  |  Page 93  |  Page 94  |  Page 95  |  Page 96  |  Page 97  |  Page 98  |  Page 99  |  Page 100  |  Page 101  |  Page 102  |  Page 103  |  Page 104  |  Page 105  |  Page 106  |  Page 107  |  Page 108  |  Page 109  |  Page 110  |  Page 111  |  Page 112  |  Page 113  |  Page 114  |  Page 115  |  Page 116  |  Page 117  |  Page 118  |  Page 119  |  Page 120  |  Page 121  |  Page 122  |  Page 123  |  Page 124  |  Page 125  |  Page 126  |  Page 127  |  Page 128  |  Page 129  |  Page 130  |  Page 131  |  Page 132  |  Page 133  |  Page 134  |  Page 135  |  Page 136  |  Page 137  |  Page 138  |  Page 139  |  Page 140