Why guests at the same table cannot hear each other, and what you can do without refurbishing

Every operator has seen it: guests lean across the table, repeat themselves and leave earlier than they otherwise would. The first response is usually to turn the music down. It helps for five minutes, then the level climbs back, because the room itself is generating the noise.

The cause is reverberation time

Reverberation time is the time it takes for sound in a room to decay by sixty decibels. In a restaurant built around conversation the target is roughly 0.6 to 0.8 seconds. Once it exceeds a second, syllables overlap and speech becomes unintelligible.

Contemporary interiors lengthen that time: large glazing, concrete or smoothly plastered ceilings, ceramic floors, tables without cloths, chairs with hard seats. Every one of those surfaces reflects sound.

The vicious circle

When people cannot hear each other, they speak louder. Because they speak louder, staff raise the music so it does not disappear into the noise. Because the music is louder, guests raise their voices again. A room that felt pleasant on opening night is exhausting at full occupancy.

What works without refurbishing

The following measures require no building work and can be introduced gradually:

• Acoustic panels on the ceiling, made in the colour of the existing ceiling. Visually almost invisible, and the single most effective measure on this list.
• Heavier curtains alongside large glazing. They work even when drawn back, provided there is enough fabric.
• Textile on the seating. Cushions and upholstered backs absorb more than you would expect.
• Timber slats on one or two walls, with absorbent material behind them.
• Rugs in circulation areas. They reduce the noise of footsteps and of chairs being moved.
• Felt pads under chair legs. The cheapest item on this list and surprisingly effective.

The order matters

These measures work incrementally and add up. It makes sense to start with the ceiling, since it is the largest uninterrupted surface in the room, and to check after each step how the space performs at full occupancy. Often two measures are enough and the third is never needed.

Where the limit lies

If a room has a four-metre concrete ceiling, glass on two walls and stone floors, cushions alone will not save it. In that case it is better to plan a serious intervention and match it to the look of the room than to add small measures for a year with no visible result.

The same applies to formal noise measurement: where one is required, for instance following complaints from neighbours, it is carried out by an accredited body. Room acoustics and environmental noise are two different matters.