Quieting a Noisy Restaurant

Posted by AcousticalSurfaces on 05/13/2008 1:43 pm | 8 Comments

V.S. Writes:

We have tile floors, wood and rod iron tables and chairs, a lot of glass windows. On a Friday night it is so loud in there I have customers complaining. We are looking for ideas and products to quiet the noise levels. Hope you can help.

Thank You

I just took another call today with someone who was also looking to quiet down a restaurant, so I thought I would put together another entry about restaurants and the challenges they pose. Almost all restaurants, even fast food restaurants, are set up an furnished in relation to the menu. The surfaces that make up the interior of the restaurants do not only need to maintain a certain aesthetic, but they need to be cleanable to maintain a sanitary environment, it is very rare to very much see carpet and carpet pad in a restaurant.

The tough part about treating a dining area is that the owner or management of an establishment does not want to change the existing look of the room that has been carefully planned. The problem with this becomes that without covering up some of the hard surfaces of the room, you can not absorb any echo. This basically means that we need to introduce some wall or ceiling panels that are either an accent to the look of the room, or install product in such a manner that it blends with the paint scheme of the room. Both can be challenging, and will usually require discussing the problem with someone at ASI, and getting some product samples and literature sent out to you.

For this example, I am going to use a dining area that is 30′ x 40′ with 12′ high ceilings. The floors in this room are made from decorative dyed concrete, the walls are painted in earth tones and the ceiling is a blacked-out painted metal roof deck with black painted HVAC ducts. This hypothetical restaurant has standard stand-alone tables in the middle of the room with wooden chairs and booths around the perimeter with vinyl covered padding. Let’s throw in some fake plants throughout the room and some pictures on the walls. The decor of the restaurant has been carefully planned to accent the food that is served.

If I were to be presented with a situation like this, my first approach would be to put panels on the ceiling. I would suggest that the panels be adhered directly to the ceiling, flush with the metal roof deck. Although there may be joists in the space that one could use as supports for a baffle type installation, this usually won’t fly because most restaurants have a fire suppression sprinkler system, and a baffle installed on the joist would inhibit the throw of the sprinkler system. That is not only unsafe, but a fire marshal would probably make the restaurant remove the panels before they opened.

What is the best panel for me?
My first suggestion for product would be the 1″ thick, #3lb density Echo Eliminator. These are panels made from recycled cotton and are available in a 2′ x 4′ panel size. They are very light, very effective acoustical panels that are some of the most cost efficient panels on the market. I am usually asked to explain the difference between the one-inch and the two-inch panels. For most restaurants, I would only recommend the one-inch thickness because of the cost to effect ratio. One of the main advantages of the two inch panel is that it absorbs more low frequency noise than the one-inch panel. For restaurants that are not pumping out music with a lot of bass in it, the one-inch and two-inch panels will perform nearly identical so there is little reason to go with the thicker panel. The one-inch panel will provide great absorption at a lower cost.

Let’s assume that the customer has gotten some product samples and decides to choose the Echo Eliminator over a few other options which I have not discussed in this write-up, the next question is quantity.

How many panels do I need? Do I need to cover the whole ceiling?
The answer to this question is going to be up to you. I have some simple guide lines that we can use to get started, but different restaurants are going to have different needs. You very well might need to get some panels into the space and assess the situation. It may be enough, and you may need to add more, the exact number might take some time to figure out based on your needs and expectations for the space. Now that I’ve explained my disclaimer, here is the equation that I use to get the ball rolling in terms of quantity, I take the cubic volume of the room and multiply it by 3% for a smaller room, and 4% for a larger room. The room that I noted above, I would consider a larger room, so I would multiply the height, width, and depth of the room to determine the cubic volume of the room. I would then multiply that number by 4% (.04) which would be the approximate square footage needed for that room.

Example: (30′ x 40′ x 12′ = 14,440) (14,440 x .04 = 576) A room of this size needs approximately 576 square feet of paneling, or seventy-two (72) 2′ x 4′ panels.

So, by now, we’ve selected the type of panel that the restaurant is going to go with as well as the quantity that needs to be installed into the space to treat that room. The next question is location.

Where do I put these panels to get the best performance?
The answer to this question surprises most people. The acoustical panels will perform the same regardless of where they are put in the room as long as they are spaced out fairly evenly throughout the room. I would suggest covering up the hardest surfaces first, but really, if seventy-two panels are glued to the ceiling of the hypothetical room above, both the returning customers and employees are definitely going to notice the difference.

The nice part about acoustical panels is that after they are installed, people will tend to be able to talk quieter and still be understood by their party. When only a few people are in a restaurant, they are able to speak in normal, soft voices and the people sitting near them are able to understand what they are saying. If the restaurant is filled to capacity, and people are not only talking, but plates and silverware are clanking, drinks are being poured, servers are taking orders and there is a little bit of background music, people have to talk in MUCH louder voices to be heard over the background noise. This phenomenon is commonly called the “cocktail party effect”. Now there are not only lots of noise sources, but these noise sources continuously increase in volume so the space is louder and louder and louder. With hard surfaces surrounding the noise sources, it can actually be louder in the room that the sum of all the noise sources because of the sound energy not being absorbed and being heard multiple times. When absorption is introduced, this problem becomes a decreasing spiral instead of an increasing one as I just explained. If people can talk in a quieter voice and still be heard by the people around them, there is less energy to be absorbed and less energy that is being reflected off of the remaining hard surfaces in the room.

Some other products that have been chosen for restaurants can be explained further, so feel free to call. These products are:

Decorative Fabric Wrapped Fiberglass Panels and Baffles

Sound Silencer P.E.P.P.

Sound Absorbing foam

Additional Resources

Creating Better-Sounding Rooms

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Solutions to Common Noise Problems

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