If you rise early enough in the day — well before sunrise, when most folks are still sleeping but when nature awakens and the wheels of commerce begin to turn — listen carefully. The still morning air is a cacophony. You might hear the newspaper deliverer, your wall clock, the HVAC system, and perhaps a train or highway traffic in the far distance. It's amazing that people can sleep with that "racket" around them; however, we have developed the ability to shut out certain sounds so that we can rest or concentrate.

That's one of the reasons it's difficult for restaurateurs to be objective about the sound levels and noise in their establishments. (As I will discuss, noise and sound level are different concepts.) We become accustomed to sound and noise, in the same way a teenager becomes used to listening to music at a volume that would drive her parents out of the house. Different customers have different expectations of what sounds and sound levels are acceptable in their environment. The teenager's parents would like a relaxing and soothing household at the end of the day. The daughter seeks more energy and stimulation. In the same vein, you need to match the "acoustic environment" of your business based on your concept, customer base, and venue.

A loud environment also affects the morale and safety of your employees. High levels of noise, over time, can affect a person's hearing. Studies have proven that sound vibrations cause fatigue, headaches and nausea. -- Susan Dickson

 

That's why among the many factors to take into account when planning your restaurant are noise and sound level. Maintaining acceptable levels can play a part in your success. But, again, understand that an appropriate "sound level" is a function of the ambience you desire. At a football game, the deafening cheers of the crowd add to the excitement and fun of the experience. In a library, a quietly tapping pencil is distracting and annoying; i.e., noisy. Consider the owner of a Mediterranean-style restaurant who enjoys the din of lively conversation and kitchen sounds, as it reminds him of an energetic European bistro. Based on the popularity of his establishment, his patrons, who seek excitement and fun, share his opinion. A white-tablecloth establishment seeking a sophisticated and romantic atmosphere might want to keep the sound level low enough for quiet conversation. Certainly, couples out for a romantic evening or business people conducting matters over dinner do not want to have to shout to be heard.

In regard to sound level, there are two objectives to consider when planning your restaurant. Your first objective is to prevent unnecessary noise or objectionable sound levels in your restaurant. The second objective is to manage the sound that occurs, whether because it is not preventable, or is acceptable within limits.

Reducing Noise

Noise is unwanted sound. Sounds that seem out of place, startling, or too loud are noise, and can adversely affect the otherwise carefully planned ambience of your operation. Just as weeding a garden involves selectively removing unwanted plants, reducing noise is simply a matter of selectively reducing unwanted sounds, whether they be conversation, heating, the venting and air-conditioning system, equipment, side-station clatter, music from an adjoining venue, or footsteps.

There are many things that can be done structurally to block or mute unwanted sounds in your dining room, such as careful placement of HVAC systems, utilities, and pipes. Use of construction materials, such as gypsum board, plaster, plywood, egg crate materials and sealant should be based, in part, on their sound-absorbing qualities. Proper location of machines that have constant noises such as ice machines that dump ice with compressors that go off and on, minimize the cumulative effect of sound. For example, if you have a small restaurant with the dining room adjacent to the bar, you will want to consider an ice machine with a roof-mounted condenser. (For more information, see "Ice: The Hard, Cold Facts for Startup Restaurateurs," Restaurant Startup & Growth, February 2004.)

If, for aesthetic or concept reasons, you choose a hard surface for your dining room, such as wooden or tile floors, you might want to consider carpeting high-traffic areas to reduce footstep noises, such as outside restrooms or in the waiting area. Requiring your staff to use soft rubber souls can reduce footstep noise and protect them from slip-and-fall injuries.

If your restaurant has a number of windows to allow guests to enjoy a dramatic view, realize that glass tends to reflect sound. You might want to consider textured wall surfaces or coverings that dampen the noise level. Window treatments, such as valances and curtains, perform the same function. Even placing a sound-absorbing material, such as foam or carpet remnants, under seats provides a sound-dampening function that is out of sight, literally.

Other hard surfaces include marble and granite, which are elegant but bounce sound like a pingpong paddle. If you have a hard floor, you should have a soft ceiling, using acoustical ceiling finishes or baffles of foam and cloth hung from the ceiling. The trick is to employ techniques that do not interfere with the concept or aesthetics of your restaurant. Arbitrary use of sound-absorption techniques, such as hanging tapestries on the wall, might work in a restaurant with an "Old English" theme, but might seem strange in a hip martini lounge geared for young professionals.

Controlling the Sound Level in Your Restaurant

A classical music recording played quietly is relaxing; turn up the volume too high and you'll run for the door. The sound of conversation and dinnerware clanking is inviting and pleasant at appropriate levels for the venue. Managing sound involves selecting sound-absorbing materials that cumulatively allow you to reach your goal: not too loud or too quiet.

On that note, why would you want to make a room more "lively," with reflective materials? Some spaces are too quiet. A "dead room" is an acoustical term for a room that has so much sound-absorbing material that there is little or no reverberation, making the acoustical environment seem dull.

The size and layout of your restaurant will affect sound level. If your bar features a live band and shares a space with a dining room, your architect might need to employ more sound-absorbing materials than if you have canned music, the volume on which is easy to adjust. When planning your restaurant remember that sound ricochets in unbroken spaces. That is why some restaurants are divided into several dining rooms or levels rather than one. Partitions can also achieve this effect, and are useful in segregating a portion of your dining area for banquets, as necessary. Work with an interior designer or acoustics specialist to find materials that will help you maintain a desirable sound level.

As noted, ceilings are ideal places to use soft sound-absorbing and reverberation-controlling materials. They don't get walked on, leaned against or easily damaged. Acoustic ceiling tiles are highly rated. Drop ceilings that have air space can "trap" sound. Baffles suspended vertically have saved many a restaurant after an opening when sound management became apparently lacking. Installing differing ceiling heights is a common tool that restaurant-experienced architects use to control sound.

Using walls and half walls is an effective way to impede sound's progress. As with so many other materials, it can be aesthetically pleasing as well, giving a sense of intimacy to your space. High booths can trap the individual conversations of their occupants and screen out other noise.

Consider the Effect on Acoustics with Every Change or Addition

You need to consciously weigh every design or decorating change against the effect it will have on your restaurant's acoustics. For example, while remodeling a former bookstore space, a restaurateur who wanted to become known for his innovative menu put lovely blue paint on the acoustical ceiling tiles, substantially altering its sound-absorbing feature from a soft surface to a hard surface. He told me that he had to use several coats as, "It just kept absorbing the paint." This faux pas earned his restaurant a reputation for an unbearably high sound and noise level.

Your intuitive sense of acoustics can deceive you. You would think that a display kitchen would seem to make for a noisy and sound-reflective environment. However, the many broken surfaces, hoods and exhausts in a kitchen make it more sound-absorbing than most would think. Chandeliers, with their glass and metal surfaces, appear to have hard reflective surfaces, but, like baffles, they are useful in breaking up sound waves. They are especially useful when hung from curved surfaces, such as domed ceilings where sound waves travel like a ventriloquist's voice. Again, that's why it might pay to hire an acoustical expert to consult with you on your design.

Preconstruction Considerations

A desirable acoustic environment begins with your blueprints. I remember dining in an elegant private dining room that shared a wall with a busy side station. Every time someone used the water tap we heard a disruptive noise. Your architect can employ various techniques (such as proper placement of plumbing) to avoid problems like these. Placing side stations, air-conditioning units, intercom systems, tables, doors and walkways at sufficient distances from the dining area, will minimize noise and make your guests happier.

Does the restaurant share a wall with another business? Consider the French-style bistro that competed with booming music of a dance club next door. Everything about the restaurant was perfect, the food, the decor, and the service. But the loud music next door every Friday and Saturday night all but ruined the ambience. Always consider your neighbors when selecting a site.

Sound Control and Your Employees

A loud environment also affects the morale and safety of your employees. High levels of noise, over time, can affect a person's hearing. Studies have proven that sound vibrations cause fatigue, headaches and nausea. A kitchen where loud equipment operates constantly can wear on a person. Employing sound-absorbing techniques and maintaining equipment properly will help maintain a quieter atmosphere and allow instructions to be clearly heard.

The Occupational Safety and Health Administration (OSHA) has directed employers to implement feasible administrative and engineering controls whenever employee noise exposures exceed an average of 85 decibels during an eight-hour period. If this occurs, OSHA requires employers to notify employees, to establish and maintain a hearing test program, and to train workers how to prevent occupational hearing loss.

The noise level in restaurants can exceed 85 decibels, exposing your business to costly fines. At particular risk for hearing damages, according to OSHA, are employees, usually teenagers who use headsets in drive-through restaurants. If the sound volume is improperly adjusted, they can be exposed to harmful noise levels.

Be forewarned: A busy restaurant can average 70-90 decibels, which is about as noisy as a subway. If you believe that your business even comes close to this sound level, whether in the kitchen or dining room, you should have the sound levels monitored to determine whether you need to comply with hearing-protection measures for your workers. For more information on OSHA industry standards, visit www.osha.gov.

Planning the Acoustics of Your Restaurant

Addressing sound level with your architect or acoustical engineer in the building or remodeling stage can save time and money. Fixing sound problems after you've completed construction or remodeling often requires less-than-elegant solutions, such as baffles that distract from the architectural lines of the building. If you brief your architect regarding your desired ambience and sound level in the design stage, she can specify the materials you need to help achieve your goals. As noted, there are numerous construction and decorative materials that absorb or reflect sound without interfering with the aesthetics of the space. Like an artist mixing paints to achieve a variety of colors, a skilled architect or interior designer can mix hard surfaces to reflect sound in combination with sound-absorbent materials for a desired effect.

-- Restaurant Startup & Growth

Sound Bites: Concepts, Definitions and Explanations

Noise. Noise is simply unwanted sound and can be loud or quiet. Sound-absorbing materials help reduce noise. This is called noise reduction. This is different from soundproofing, which makes a room impervious to sound. Sound-proofed rooms would be uncomfortable for guests. A padded cell is soundproof.

Sound. Sound is that which is heard, according to one Webster's dictionary. If a tree falls in a forest, and no one hears, does it make a sound? Well, no, but it does still create waves, they just aren't reaching our ears. Sound is produced by an oscillation in pressure in a medium. If the medium is air, sound will travel at 1,130 feet per second. (In water, sound travels at 4,900 feet per second.) As these oscillations pass through a medium, air in our case, they produce wavelike motions. The distance between two identical waves determines its wavelength. The time interval between each oscillation determines frequency.

How Sound is Measured. Sound frequency is measured in hertz (Hz), or cycles per second. A person with normal hearing can perceive all sound frequencies from about 20 to 20,000 Hz. Most acoustic materials are rated according to their ability to absorb in hertz. Understanding this can help in selecting materials that will absorb the amount of sound you desire not to hear reflected.

Length of sound varies with frequency and the lower the frequency, the longer the wavelength. Our ears are less sensitive to low frequencies than high. Low sounds measure fewer hertz than high-pitched sounds. We don't hear longer wavelength variations as easily as shorter ones. A shrill noise seems more grating than a low hum. In a bar, guests will perceive the pitch of a blender as more irritating than beer coolers that are less discernable. The blender will also seem more intrusive because it starts and stops unpredictability, while our ears will become accustomed to a constant hum.

Sound intensity is expressed in decibels, or dB. This is a logarithmic scale where basically the more intense a sound, the higher the decibel rating. For example, a conversation averages 20 dB while sounds on a street corner might register 50 dB. A busy restaurant averages 70-90 dB. That is about as loud as a crowded subway station. Does that fit your ambience? If it doesn't then chances are you also think subways are noisy.

Acoustics. Acoustics is defined as the science of sound, its production, transmission and effects. When we refer to sound reflection, absorption, reverberation, and so on, we refer to the acoustical properties of sound and of materials. An acoustical environment takes into account the components of an area in reference to its ability to absorb sound. Every construction material can be rated for its ability to absorb sound. Most materials have sound-absorption specifications rated in hertz.

Initial Sources

Acoustics.com is a Web site that has a wealth of information on managing sound in public establishments. Acoustics.com touts itself as an alliance of educators, experts and design professionals dedicated to promoting the importance of acoustics in the architecture, design, construction and building communities, as well as to the general public. Among its useful resources is its collaborative arm RestaurantNoise.com.

Among the valuable information provided by the site is the article, "Do You Want Earplugs with Your Soup? The Importance of Acoustics in Restaurants." Check it out at acoustics.com/ ra_restaurantnoise.asp.