Work With Island - Is the acoustic booth really soundproof?

Is the acoustic booth really soundproof?The solution for a quiet working environment

According to a study by OpinionWay, 60% of workers in all sectors say they are bothered by noise in their workplace and this has a strong impact on their productivity. In this context, the acoustic cabin seems to be the perfect answer to this problem. Whether you need to isolate yourself, concentrate or make a phone call, the phone box has been designed to improve the quality of life at work. But is it really soundproof? Are all phone boxes equal? Our return below.

What is sound insulation?

To understand how a sound booth works acoustic booth it is
important to distinguish between acoustic insulation and
phonic insulation.

Acoustic insulation aims to avoid the propagation of all
noises while sound insulation is intended to absorb
voice sounds.

It is therefore important to look at the total reduction of the
speech level in decibels of your soundproof booth. The reduction is interesting from 25 decibels. Beware of phonebooth manufacturers who promise you an insulation of more than 40 decibels, this is surely the performance of a wall and not of the booth.

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Composition of the acoustic cabin

Sound has a series of different frequencies and amplitudes. Each material,
depending on its properties, absorbs a certain type of wave. Below, you can
discover the different phenomena when sound comes into contact with a surface.

As can be seen in the diagram to the left, four phenomena can occur depending on the surface material. For example, if the medium is a very solid and hard material such as wood or glass, most of the sound will be reflected. Rubber, on the other hand, absorbs much of the sound. In the case of foam, most sound will be absorbed, although some will penetrate it and reach the other side. These events can sometimes occur at the same time depending on the material. However, in order to guarantee a perfect acoustic insulation of the phonebooths, it is essential to superimpose several types of materials. 

Note: Absorption is the key to avoiding an echo effect. Good absorption will allow the person on the other end of the line to hear you clearly.

What materials are used to make the
the Island cabins?

As we have seen previously, the materials used are very important because they have a direct impact on the acoustics. These materials vary from one manufacturer to another, so we will focus on those used by the Work With Island teams.

The walls

To make up the walls of our Island cabins, we sandwiched three different materials to absorb the overall noise. Let's take a closer look at the materials we chose. We use an asymmetrical wall structure. Placed between the wood and the felt, Métisse®, an acoustic insulation made from recycled textiles, will act as a spring and contribute to the sound attenuation.

The diagram on the left illustrates the principle of operation. The first rigid wall reflects part of the noise. Partly absorbed by the insulation, the residual noise will be reflected by the second facing panel. In the end, only a small residual part of the sound emission will pass through the 3 layers.

The door

The door is a very important element of the acoustic cabin because once closed it must guarantee the absorption of noise. Our engineering team opted for an 8mm thick tempered glass door, which is denser and therefore more insulating than Plexiglas. Also, its transparency allows the light to penetrate inside and not suffer from the smallness of the cabin.

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What is the ISO 23351-1 standard?

Issued in 2020, ISO 23351-1 is specific to partitioning elements such as office phone booths and other semi-enclosed furniture assemblies (conventional workstations, partially enclosed sofa groups, etc.). Its purpose is to measure the ability of booths to reduce the user's speech level. The ISO 23351-1 score evaluates the speech privacy and noise reduction of the product. It calculates a number called "speech level reduction". This indicates the degree of speech privacy the product provides. And the higher the score, the better the privacy.

Why is it necessary to take into account the ISO 23351-1 standard?

The main criterion when a company invests in an acoustic booth is noise reduction. While acoustics is the primary selling point, it can also be a source of confusion for the customer because some manufacturers are not certified and decide to measure the performance of their booths themselves.

What is the problem with this practice?

These companies tend to embellish the acoustic level by measuring only the performance of the acoustic panels rather than the overall performance of the cabin. As a result, they will only communicate on the sound reduction index (Rw). This index characterizes the ability of a material or a partition to attenuate the direct transmission of noise. And not surprisingly Rw has better performance than the index communicated by the ISO 23351-1 standard.

The concern with this process is that it does not take into account glass doors or ventilation ducts which contribute to the overall insulation level.

How is the test conducted
ISO 23351-1 : 2020 ?

The test is quite simple. We measure the speech level with and without the booth (see diagram on the right). The measurements are then compared to calculate the total reduction in speech level in decibels achieved by the acoustic booth.

For information, the ISO 23351-1 standard classifies booths into several categories: A+, A, B, C or even D according to the reduction of the speech level. Those classified in categories A+, A and B guarantee the best soundproofing.

Please note: All Island cabins are rated Category B, which offers you considerable comfort and privacy for your conversation.

Would you like more information or would you like to test the acoustics of our cabins?

We invite you to contact us by email at contact@workwithisland.com.