Sound masking technology that allows guests to control their room’s acoustic ambiance
by NIKLAS MOELLER
Noise frequently tops the list of complaints from economy to luxury. It irritates guests during the day, prevents them from relaxing in the evening, and affects their ability to sleep long after they have otherwise acclimatized to their surroundings. However, as demonstrated by the JD Power North American Hotel Guest Satisfaction Survey, the majority do not complain about this problem. Instead, they simply decide not to return to the property, leaving owners/operators in the dark – until they read the unflattering online reviews.
An incomplete approach
Once aware of this problem, most hotels attempt to address it using traditional tools. For example, in an effort to block exterior noise and prevent interior transmission, properties typically increase construction standards for walls, windows, floors and doors. They also try to make noise sources within the rooms (e.g. HVAC, plumbing, minibars) quieter. Although these methods are a necessary part of an acoustical plan, it is impossible to eliminate all noise.
Furthermore, the lower a guest room’s background sound level becomes as a result of these initiatives, the easier any remaining noises – even those at low volume – are to hear. In fact, owners/operators might be surprised to learn that noise peaks to which guests are subjected are often not much greater than 40 A-weighted decibels (dBA). While one would not usually describe these sounds as ‘loud,’ they are disruptive in the context of the pin-drop background sound levels (i.e. 28 to 32 dBA) exhibited by most guest rooms.
What disrupts sleep?
Studies show that as the change between a room’s background sound level and intermittent noises increases, so does the likelihood of sleep disruption. Essentially, the more significant the variation in volume, the harder it is for guests to ignore a noise. That is why, for example, the bursts of noise from infrequent traffic are far more disruptive to sleep than the relatively constant sound produced by high-density traffic. Individuals sleep better in environments with continuous sound of a certain level than in environments with intermittent noises of the same average level.
Noise can also impact guests’ sense of privacy. Beyond general annoyance, when a noise or voice enters an occupant’s room (e.g. from another guest’s television or a conversation in the hallway), the intrusion can violate their sense of physical separation from others and make them self-conscious about their own level of privacy.
Controlling background noise
In order to reduce the number of disruptions caused by noise, one has to control the frequency and magnitude of volume changes within guest rooms. While steps should be taken to reduce the amount of noise generated in the first place, it is clearly impossible to achieve silence. Providing a higher and more consistent baseline level, on the other hand, can easily be accomplished.
Adding more sound to a space may run contrary to most people’s understanding of how to control noise, but the premise is simple: any noises that are below the new background sound level are covered up, while the impact of those above it is lessened because the degree of change between the baseline and any volume peaks is smaller.
This is an effect with which most people are already familiar. Everyday examples include the drone of an airplane engine, the murmur of a crowd in a busy restaurant, the hum of highway traffic, and the rustling of leaves in the wind. All have the potential to mask sounds a listener would otherwise hear. Indeed, out of frustration, guests often try to use the HVAC system in this manner because they instinctively know it will cover up at least some unwanted noises. However, these systems are not designed for this purpose. They cycle on/off and do not produce the correct sound spectrum or level. When used excessively, energy consumption and maintenance costs also increase.
The background sound level is best controlled by introducing sound masking technology to each guest room. Though this sound is typically compared to softly blowing air, unlike ventilation, clock-radio style ‘white noise’ products or mobile apps, a commercial-grade masking device produces a sound that follows a particular spectrum that is engineered to balance acoustic control and occupant comfort. The sound is produced over a high-quality loudspeaker and adjusted via fine volume and frequency controls.
Because most noises entering guest rooms are near or below 40 dBA, they are easily masked by a relatively low level of masking (i.e. 40-45 dBA). Though the masking sound will not always completely cover an offending noise, it will substantially reduce its disruptive impact. Because noise can span a wide range of frequencies, the masking device must be capable of outputting frequencies down to the 100 hertz (Hz) level. If it does not output frequencies at the frequency of the noise, the sound will not provide as great a degree of masking benefit.
A surface-mounted control pad or wall-mounted dial allows guests to adjust the volume according to personal preference or as needed to cover disturbances. In other words, occupants can control their room’s ambiance the same way they control its temperature and lighting.
Introducing sound masking to guest rooms shows a proactive approach to dealing with noise. Alternatively, if a hotel identifies problems after opening, this solution is far more cost-effective than pursuing further structural improvements or replacing equipment, particularly given the recent introduction of ‘bolt-on’ commercial-grade masking solutions. That said, in the hospitality industry, it is far better to prevent a poor experience than try to fix one after the fact. ■
Niklas Moeller is the vice-president of K.R. Moeller Associates Ltd., manufacturer of the LogiSon Acoustic Network and MODIO Guestroom Acoustic Control. He has more than 25 years of experience in the sound masking field. Moeller can be reached via e-mail at [email protected].
PHOTO CREDIT: ANA BLAZIC PAVLOVIC/FOTOLIA