Good acoustic design is integral to delivering a great customer experience, but all too often it is overlooked in the design of an operation.
Controlled acoustics means that your guests are more comfortable and will stay longer, potentially spending more. But, particularly in restaurants, acoustic considerations are left to the end of the project.
Hotels fall under the remit of the Building Regulations, of which Approved Document Part E (ADE) stipulates acoustic performance criteria for all separating walls and floors, including the provision of acoustic absorption in communal areas. It requires guest rooms to comply with performance criteria for "rooms for residential purpose" and should be considered at the early design stage.
However, restaurants are not governed by any statutory building performance criteria and are usually only subject to client-specific requirements. A client's brief will typically include a summary of what level of acoustic performance must be achieved, with some restaurateurs placing little importance on acoustic design. Others will consider acoustics to be critical in addressing customer satisfaction.
Academic research shows that noise can affect how we taste food intensity and quality, with noisy restaurants perceived to be serving less sweet or less salty food. Such findings may well come as a surprise to many restaurateurs.
As a worst-case, therefore, a poor acoustic experience could impact on revenues by curtailing repeat business.
Alex Krasnic is an acoustic engineer at ZBP Acoustics
Acoustic design considerations
1 Reverberation times in communal and dining areas are critically important. Spaces which contain a lot of "acoustically hard" surfaces (such as glass, metal, unperforated timber, stone and ceramics) will result in very reverberant or "echoey" conditions. The longer the reverberation time, the greater the sound will be amplified.
2 Noise from building services is crucial and one that often defines the most comfortable establishments. Noise from public health and mechanical services including lifts, should all be considered with a view on the acoustics.
"Cross-talk" is another acoustic issue often overlooked. This describes how speech can invade one space to another, whether through services ducts or through free air in a dining area.
3 Site orientation and local ambient noise are important during planning, in particular where the hotel forms part of a wider, mixed-use development. Local planning authorities will usually expect provision of ambient noise data and noise ingress assessments.
4 Achieving good speech privacy between rooms involves striking a balance between low ambient noise and partition sound insulation. The minimum performance to ADE is unlikely to be sufficient in achieving good speech privacy with partitions separating quiet guest rooms requiring superior performance.
5 Most architectural elements, from glazing optimisation (including weather-stripping and opening lights) to specification of doorsets, will require a good acoustic performance. Resiliently-mounted TVs and loudspeakers help to minimise structure-borne noise and voice alarm systems must be intelligible throughout.
ADE also stipulates performance criteria for impact sound through floors, which can be controlled using specialist acoustic techniques. In certain cases, balconies can also be used to provide some degree of external noise reduction.
6 Reducing noise in dining areas may be important for certain operations. The Lombard (or "cocktail party") Effect describes how talkers in a closed space will attempt to compete with one another through ever-increasing speech levels (a common phenomenon in reverberant or naturally noisy spaces).
7 As with hotels, ingress from external sources will only add to operational noise levels resulting in a less palatable experience (and most likely exacerbating the Lombard Effect).
8 Spatial arrangement can also affect the acoustics. Is it necessary for a noisy kitchen observing area to be close to dining areas, or are screens, partitions or lobbies preferable?