In the end, thanks to a tip from the man responsible for the rebuilding of the concert hall within the Royal Festival Hall and all its attendant acoustic challenges, I got in touch with Alan Saunders, the softly-spoken, 58 year-old managing director of his own firm of acoustics consultants.
Saunders’ company has an international reputation for dealing with the aural challenges not just of numerous modern buildings such as the entrances to hotels and office buildings (he worked on the boardroom in Enron’s London HQ, for example, and in the end his company was left with an outstanding debt of only £1,500, he told me proudly) but also, most recently, to the possible noise implications from a proposed oil pipe line in Azerbaijan on ancient cave paintings in a part of the countryside it will pass through.
What I didn’t realise as we sat down to lunch in Kensington Place, a restaurant as well known for its continually high noise levels as for the accomplished cooking of my colleague Rowley Leigh, is that Saunders is an enthusiastic cook, describing himself as ‘a bit of a tyrant in my own kitchen with only his 21 year old daughter ever allowed to help,’ and that this was his first visit to what has come to be known by its many regulars as KP.
As we sat down just after 1pm the restaurant was more than half full and already quite noisy – something Saunders chose to explain even before I could him ask any questions. “Perhaps, not surprisingly, it’s the acoustics I notice first whenever I walk into any building. Others may look at the space and find particular charms but I am always struck right away by whether a building is acoustically good or not. And it is trying to convince my clients of this, and its importance on those who will use the building in the future, that is my biggest professional challenge and frustration.”
“But let me start with a few generalisations. The most important is that given the number of people who are already in this space, and I reckon that there must be about 80 or more, whatever they were doing in here would generate a pretty high level of noise. It is not like this simply because it is a restaurant. The most influential factor in the noise level here and in so many other restaurants is the space and the proximity of so many tables within it. The restaurateur has done this not just to create an ambience by allowing as many people to see one another as possible but also for sound financial reasons which I fully appreciate. If you were to halve the tables in here you would halve the volume but you would have to double the prices, I expect. But the effect would be significant. I reckon with half the tables in here you would cut the noise level by 10/15 decibels which is about what you achieve when you close the front door of your house on the traffic noise outside.”
As he tucked into an imaginative first course off the set lunch menu, a salad of wild asparagus and mousseron mushrooms topped with a poached egg, Saunders continued, “But what will happen pretty soon with such a concentration of people as close together as this in a restaurant is that what we refer to as ‘the Cocktail Party Effect’ will take hold. That begins to happen when, invariably induced by a glass of wine or two, people begin to talk louder and louder and then, to make themselves heard against the increasing volume their voices just continue to rise until many of us have to resort, consciously or otherwise, to lip-reading.” Saunders was to be proved right and the second half of our lunch took place against a much noisier background than the first.
Having discovered that Saunders had also been chairman of the Association of Noise Consultants, I asked him what practical advice he could offer to those who wanted to enjoy the conversation as much and as easily as the food and wine.
“The important thing to remember about acoustics is that it is a fairly new profession and I think it is one that is getting a lot of attention at the moment because there is no doubt that as people age their hearing suffers, just as their eyesight does. People suddenly become aware of this and want solutions. But in a restaurant setting these are invariably difficult to introduce effectively because either the architect or the interior designer has not bothered to consider the subject or, if they have, because the restaurateur does not have any budget to deal with what is, in reality, an invisible problem and one that only affects a certain percentage of his customers.”
But would tablecloths, curtains, an abundance of soft furnishings and that old but unscientific tactic of sticking pieces of felt under the restaurant’s tables have any effect I asked Saunders? “On their own each of these has little effect. Collectively, and only collectively, they do help but for example soft floor coverings don’t do much because the floor is then covered by tables which in turn have to be covered by sound absorbent tablecloths to maintain the effect.”
“Let me deal with the physics, briefly. In any room there is direct sound, perceived exclusively by the listener at no more than 1.5 metres from the speaker and at distances greater than this, reverberant sound, which you hear more of the further away you are from the speaker. This combination, plus the consequences of the cocktail party effect, means that the restaurateur is basically up against it. No form of intervention will completely control the problem only make it better although any form of minimalist interior design will only make it worse than it need be.”
“You can only reduce direct sound by putting the listener further from the speaker, the very opposite of why people come to restaurants, or by introducing a screen between them.” Taking my notebook, Saunders drew a diagram of the restaurant with two floor-to-ceiling screens in place, one at either end, which would do just that. “These could be glass but if they were material they would absorb the sound much better as would some banquette seating.”
“The amount of reverberant sound is related to how acoustically hard the surfaces in the restaurant are. Today, most modern interior design invariably incorporates glass, metal and plasterboard which only absorb sound at low frequencies and, unfortunately in the frequencies associated with the intelligibility of speech, these reflect sound almost completely.” To prove his point, Saunders pushed the restaurant’s glass exterior and added “This just bounces the sound round and round.”
“To absorb sound a room needs soft materials and for these to be most effective they need to be on the walls or ceiling where they are uncluttered. Acoustic foams, mineral or rockwool, glass wool (like loft insulation) all have good acoustic absorption, that is they do not reflect much of the sound which hits them and to-day, to make them aesthetically acceptable, they can be placed behind perforated plasterboard, timber or metal panels. Also, again unlike here, anything that the designer or restaurateur can do to diffuse the sound by using the shape of the room, or surfaces within it, to reflect the sound as much as possible and in as many directions as possible will also help. This is the principle used in the design of concert halls and recording studios but contoured artefacts, such as those on the walls of TGI Fridays do the job, too.”
“The moral of all this, “ Saunders concluded with a smile, “is that the old-fashioned Indian restaurant with banquette seating, flock wallpaper and thick velvet curtains gave a much better acoustic environment for eating than so many modern restaurant designs today.”
