It took me far longer to track down the most suitable person to answer the question FT readers have been putting to me for some time now - why are so many modern restaurants so noisy? - than to think of the most appropriate restaurant in which to meet.

In the end, thanks to a tip from the man responsible for the rebuilding of the Royal Festival Hall's concert hall, I got in touch with Alan Saunders, a softly spoken, 58-year-old acoustic consultant.

Saunders's company has an international reputation for dealing with the aural challenges of numerous modern buildings such as the entrances to hotels and office buildings. Most recently, he consulted on the possible noise implications of a proposed oil pipeline in Azerbaijan.

What I didn't realise as we sat down to lunch in Kensington Place, a restaurant as well known for its 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 his21-year-old-daughter ever allowed to help.

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 that 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. However 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 of salad of wild asparagus and mousseron mushrooms topped with a poached egg, Saunders continued. "What will happen pretty soon with such a concentration of people as close together as this 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 with the second half of our lunch taking place against a 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 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?

"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 1.5m from the speaker. At distances greater than this, there is 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 the tables." Taking my notebook, Saunders drew a diagram of the restaurant with two floor-to-ceiling screens that 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 incorporates glass, metal and plasterboard, which only absorb sound at low frequencies and, unfortunately in the frequencies associated with the intelligibility of speech. In fact, they reflect sound almost completely." To prove his point, Saunders touched 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 by other objects.

"Also, anything the designer or restaurateur can do to use the shape of the room or surfaces within it to reflect the sound in as many directions as possible will 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."

Alan Saunders Associates, tel: +44 (0)1962-872 130; www.alansaunders.com

More restaurant columns at www.ft.com/lander