Acoustic improvement in restaurants, bars, cafes and other hospitality stores

In addition to the right soundproofing materials to avoid noise leakage to sound receivers, a particularly important acoustic factor is the right architectural acoustics inside an acoustically sensitive area.

The overall sense of satisfaction that a patron receives from a hospitality space is heavily dependent on the acoustic comfort that is defined by the sound absorbing material of the space. It is important to remember the difference between soundproofing materials and porous sound absorbing products.

Modern architectural philosophy includes minimal structures with marble floors, plenty of glass, hard surface tables, modern ceilings, mirrors, etc., which all have a low sound absorption coefficient. All of these contribute to increasing the noise produced through reflections and a generally unattractive experience no matter how good the food or the service are.

In practice, poor acoustic design is assured by the need for a high sound level of speech (screaming) to communicate with adjacent people who are usually no more than a meter away. The end result that a client receives is a stressful, not relaxing experience.

Cutlery, chairs, coffee makers, glasses, etc. They add to the overall noise level and often even communication between staff is difficult, which can lead to mistakes in orders.

The generated noise level inside the restaurants depends on many variables such as the relevant license / legislation, the character of the store and the culture of the country.

For example, as shown in the diagram below (Lauren H. Christie Victoria University of Wellington) in New Zealand, the average measured sound level of background noise is significantly higher than bars and cafes.

graphAccording to the same study, restaurants are the most popular going out destination for communication (compared to a bar / café) as shown in the diagram below:

graph yellowConsidering the above acoustic data, this study concludes in the following diagram of noise ratio.

graph purple

As is clear, human communication of other patrons accounts for over 60% of the generated noise.

In view of the above, it is clear that achieving a suitable audible atmosphere for restaurants in order to allow for an understanding of the conversation between patrons at the same table is not an easy task. It is also important to mention that the use of soundproofing materials will not assist at all to sound absorption which requires materials with acoustic porosity.

In order to further study the subjective impression of acoustic comfort, analytical sounds were performed by the Monika Ryhavakora team at the University of Lausanne in Belgium.

A large database of 11 restaurants with 75 measurements for each (825 in total) gathered for analysis. The results show that a certain narrow range of reverberation time can produce audible comfort for restaurant customers of all ages. Other physical and acoustical conditions of the dinning area appear to have little or no consistent effect on comfort recording. The results also show that the various subjective components of acoustic comfort – quietness, communication, privacy – vary considerably by age group with specific implications for audible design of restaurants for different customers. For this reason, the acoustic comfort of indoor space is more difficult to predict than sound insulation and sound-insulating materials to transmit noise to the environment.

According to the more extreme research findings, some restaurants may be noisy to a level that exceeds the instructions for noise at work. This may give the illusion that the store is “alive” but in practice a remarkable percentage of customers the research shows they will not return.

Taking into account the use of relevant applications, social media and general use of the internet, a poor critique or negative rating can directly affect potential guests of the café, bar or restaurant.

A notable example of restaurant rating is Michael Bauer of San Francisco Chronicle, who uses “bells” as a measure of hearing comfort. In this way, it can classify the noise level in the restaurants that are considering judging from the final result, and not if sound-absorbing materials have been used to increase the property or, in general, there is sound absorption in the room. Specifically for restaurant reviews: one bell (under 60 decibels), 2 bells for conversations that are easy to talk (60-70dB), 3 bells means speech is usually difficult (70-75dB). 4-bells, prevailing voices and communication is done only with difficulty (75-80dB) and “bomb” when it is very noisy. (Over 80dB).

Solutions

With the significant progress in sound insulation materials and sound absorption materials over the last few years, the available solutions for an acoustic engineer are diverse. The challenge is to combine a right acoustic environment with proper aesthetics and ergonomics, so that it is balanced in all levels.

The overwhelming majority of audible improvement of bars, cafes, or restaurant areas has to do primarily with interventions on the ceiling and secondarily on the walls. This is because in high ceilings the ceiling surface is often free with air conditioning, ventilation and lighting fixtures. ALPHAcoustic AP Cloud sound-absorbing panels can easily be placed between the obstacle gaps and make use of the ceiling’s free surfaces.

Indicatively, below some pictures of sound absorbing frames mounted on ceilings and restaurant walls, cafes and bars to reduce reverberation time are presented below:

Restaurant acoustics21

Our company, aiming at the continuous development and improvement of solutions for sound absorbing materials, has created a new range of acoustic materials for use in hospitality areas. These new products are called ALPHAcoustic-AM and can be used as sound insulating materials for primary noise reduction or as sound absorbing products that reduce reflections in space.

What are the self-sounding ALPHAcoustic-AM sound absorbing frames?self standing

ALPHAcoustic-AM self-supporting sound absorbing frames consist of a strong internal frame. They are covered on all sides with a special sound-proof fabric in a variety of colors. Inside, they carry a fibrous, non-combustible, sound absorbing material that can be covered with an additional protective film.

They have increased sound absorption capacity across the range of acoustic frequencies with a sound absorption coefficient of 0.9 at 1000 Hz, according to ISO 354.

They offer a flexible and affordable solution to a lot of room acoustic improvement by improving sound diffusion and preventing the production of stagnant waves.

Where can they be used?

They can be used as dividers between similar spaces as well as for separating musical instruments and patron tables eliminating the direct diffusion of sound. They are also a recommended solution in cases where it is desirable to partially isolate in public places by offering appropriate privacy and relative compartmentalization of the site.

They are easy to install in any room and are moved with the same ease of change in space.

APPLICATIONS / MODIFICATIONS OF IMPROVEMENT

Insulation of Sound Absorbing Frames

ALPHAcoustic-AM sound absorbing frames can, depending on the architectural and aesthetic requirements of the space, adjust their final surface and investment.

In this way, the frame is not only limited to its utilitarian value (acoustic improvement), it is also a decorative intervention in the space itself, offering the flexibility of forming a dynamic frame adaptable to any decorative option without distinguishing it as belonging to the soundproofing class.

Alternative 1

Initially, the ALPHAcoustic-AM soundproofing self-supporting frames can be externally coated with fabrics of different types and colors.

 Alternative 2

A new alternative to lining the frames is to cover the final surface in a “button style” form. In this way the feel of the panel is more light, while its edges round and smooth. This proposed additional specification is presented in the following photographs and is a unique aesthetic feature for soundproofing materials that rarely combine acoustic results and high aesthetics.

alternative 2

Self-supporting panel in the form of a bottler and a color of two-tone brown fabric

Installation of Sound Absorbing Frames

Alternative 1

ALPHAcoustic-AM self-supporting sound-absorbing frames can be supported at the bottom in 2 metal legs, so they can easily be mounted on the floor of the room or even between tables for application as sound insulating materials in restaurants, cafés and bars.

This way of stacking gives them the following advantages:

  • autonomy of each panel in the space
  • Create any desired layout and placement at any distance between them
  • Easy to move and store.
  • By using legs, the seat frame is very safe in any overturning action, and the overturning of one does not pose the risk of overturning other frames due to the aforementioned autonomy provided in this way of restraint.

However, this particular mode of attachment has some disadvantages to be mentioned:

  • The footrests protrude at the bottom of the panel by 17cm on each side. This creates the necessity of having a space of at least 40cm to correctly push the panels.
  • The leg projection is dreaded to cause accidents from people in the area.

legsLeaning of frames using legs

It should be noted that in this scenario it is possible to replace the metal legs by wheels that will lock when placed in their intended position and will allow easy movement for position change when desired, depending on the use of the soundproofing materials.

Alternative 2

Another alternative method of supporting and installing the sound absorbing frames is the use of special hinges.

In this alternative, the following two configurations are available:

In the first configuration it is proposed to supply the panels separately and to assemble them (hinge fitting) on site.

It should be noted that different types of hinges are proposed to meet aesthetic and functional requirements.

  •  Large INOX hinges that will be placed at the top and bottom of the two frames for their retention.

inox

fabric panel

By applying the above hinge, the acoustic panels (soundproofing materials) are supported by creating a mating configuration between them and essentially holding each other. However, a small gap is created between the frames which can cause loss of sound absorption. Also, the rotation of the frames between them is only observed at 180 ° (see Annex 2).

  • Small INOX hinges that will be placed at the top and bottom of the two frames to secure them.

small inox

By applying the above hinge, the opening between the two frames is even more limited. Moreover, due to its size it is a more discreet choice in terms of aesthetics.

  • Place a small blade at the top and bottom of the panel assembly in front of the hinge.

hinge

v shaped

With the installation of a small stainless steel blade, it is ensured that the frames are connected, without the coil being clearly visible. It is also possible to rotate the 360 ° frames, thus allowing greater freedom in the selection of the panels in the space.

The advantages of the above configuration are:

  • Freedom to place panels that are required each time
  • Easily move and store individual frames.
  • Ability to have a smaller bearing surface (Annex 2)

However, there are some considerations in this configuration, such as:

  • Difficult installation of soundproofing materials (acoustic panels) every time
  • Falling one frame means dropping all the dominoes
  • There is no complete freedom in the arrangement of the soundproofing materials in the space since in terms of static the horizontal arrangement is considered dreadful and in the case of the classic hinge the opening of the frames is up to 180 °.

It should be noted that in order to address the problems of installation and the creation of domino in the event of a fall, double coupled frames are strongly proposed.

Brief installation scenarios

Table English
Below are some suggestions and scenarios that can be followed by a choice in a restaurant for audio cut-off between the tables.

restaurant 1

Acoustic Panel structure with hinges

restaurant 2

Acoustic Panel structure with metal legs

curves

Surface on the floor required for both cases

panel 1

panel 2

drawing 1Width of panels connected with hinges

drawing 2

extend of acoustic panelsExtend of panels connected with metal part

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