Dining is a social activity with deep cultural and emotional underpinnings. Gathering around the table with our families and friends to share a meal enriches our lives and strengthens personal connections with others.
As individuals grow older, the likelihood of isolation and withdrawal from social activities can increase because of the increase in health problems, including hearing loss. Hearing loss is the third most prevalent chronic condition in older Americans, and it is the number-one communicative disorder in this population; 25% to 40% of the population aged 65 years or older has hearing loss (Yueh et al., 2003; Frisina et al., 2006).
The social activity of dining in long-term care facilities becomes even more important to maintain a sense of well-being. Because good communication is fundamental to social activities, a key factor in designing dining spaces for an older population is the acoustic environment. When considering older diners, designers should assume that many have some degree of hearing loss. Because of variations in age, gender, medical condition, and use of amplification devices, achieving the ideal acoustical balance for any given population requires attention to a number of factors.
In most situations, the speech we want to hear needs to be louder than the background noise (the signal-to-noise ratio). In the design of dining spaces, the two primary acoustical factors to consider are background noise, or noise criteria (NC), and reverberation time (RT). If the NC and RT in the dining room are too low, diners will sense a lack of privacy for conversations. Conversely, if NC and RT levels are too high, speech intelligibility may be lost in conversations at each table. The ideal dining room acoustics require background noise and reverberation to be just high enough to make conversation at one table incomprehensible at an adjacent table, but just low enough to keep the same conversation intelligible and accessible to everyone seated at the table.
In dining spaces, background noise can arise from noise outside the facility (such as traffic) or inside the facility (from the heating and ventilation and other mechanical systems or from noise in other spaces, such as the kitchen or dishwashing area via the tray-return window). In a room with minimal background noise, it may be desirable to increase the background noise level through speakers that pump music or "white noise," which the brain generally disregards after several minutes because of the low frequency. Reverberation time is a affected by the amount of hard or soft materials within a space. In a room with mostly hard, reflective surfaces, the sound takes a long time to die. In a room with mostly soft, absorbent surfaces, the sound dies away quickly. If the goal is to reduce the acoustical "liveliness" in a space, adding carpet, draperies, linen table cloths and upholstered seating with some padding are possible options.
Speech Intelligibility Zones
Separating and isolating the noise from the kitchen can help when creating zones for better listening. These zones can be planned in the dining room to permit a more pleasant dining experience for all diners regardless of their hearing abilities. Design strategies to be used in planning these zones include the following:
- Provide sound-absorptive materials on one side of an open room and hard surfaces on the opposite end.
- Reduce reverberation time by creating irregular room angles with soft materials applied to wall surfaces.
- Establish secondary smaller rooms with lower ceilings, which lower the RT, adjacent to primary large rooms with tall ceilings. Include wide double doors between the two spaces to enhance acoustical flexibility and degree of connectedness. When the doors are closed, the space will be separated acoustically from the adjoining larger open space (better if intimacy is desired); when the doors are open, the space will feel more connected to the larger space (more desirable during a special event or large gathering).
- Apply appropriate hard or soft finish materials on walls and ceilings where they are most effective. In many instances, the amount of carpet on the floor has less acoustical impact in dining spaces, due to the amount of furniture on the floor and the fact that the sound from the occupant's speech is travelling horizontally in many different directions. Furthermore, flooring materials favored by many dining venue operators—hard surfaces like terrazzo, resilient goods, or porcelain tile—have good durability and are easier to keep clean; as a result, carpet may not be an option under any circumstances.
- Differentiate large open spaces with architectural elements. In such rooms with mostly hard surfaces (and high RT), the addition of partial-height walls or drapes help to subdivide the single large space into several smaller zones that are not as acoustically lively. These features also enable the application of softer materials to help absorb sound.
- Furniture type and layout is an interior design consideration that also affects the acoustics of a dining area. For flexibility, use a mix of various types of furniture and arrangements to accommodate a range of hearing abilities. Standard, square, four-seat tables can be arranged throughout the room individually to accommodate either two or four (for those who have difficulty hearing conversations in large groups); the same tables can be pushed together in a row or U-shape for a larger banquet function or lecture. Spacing of tables is also important. Tables spaced too closely will result in the distraction of hearing a neighbor's conversation and diminished speech intelligibility.
A possible downside to the creation of acoustical "zones" is the tendency of diners to segregate by congregating in groups throughout the room because of their subconscious acoustical preferences. Although this tendency may be overcome with proper staffing, it is likely that people are already somewhat segregated by age and social preferences. The benefit of having wide range of dining options with carefully crafted acoustical conditions can promote greater interaction.