Acoustic fabrics allow to improve the acoustic comfort of enclosures offering a wide range of acoustic solutions in both acoustic insulation and conditioning. Acoustic fabrics can be used in a multitude of enclosures such as theatres, private homes, restaurants, shops or studios.

In addition, acoustic fabrics offer numerous advantages. Some of them are:

  • Versatility: they can be used in all kinds of activities.
  • Easy to install: their lightness makes them easy to install, reducing its installation time and avoiding in shops the need to stop the activity.
  • Design element: their variety of colours and sizes gives them decorative value.
  • Compatible with other acoustic solutions.
  • More economical than other acoustic solutions.
  • They can be used as separating elements without the need of raising partitions.
  • They can be used to cover windows, to guide and control the lighting in the room.

WHICH FABRIC DO I NEED?

ACOUSTIC SOLUTIONS: ACOUSTIC INSULATION AND CONDITIONING

In general, we can divide problems generated by excessive noise into two main groups.

acoustic isolation

Against noise coming from outside Against noise coming from outside.

Problems due to noise coming from outside: noise from a noise source outside the enclosure – another enclosure, the street, traffic, etc. – reaches the room.

acoustic conditioning

Against noise generated inside the room: acoustic conditioning.

Problems due to noise generated inside the venue: in its normal activity, reverberation is generated inside the venue, creating a feeling of noise that makes it difficult to hold conversations -common in restaurants, studios, minimalist venues, etc.

In TEXTIL BATAVIA we have ACOUSTIC FABRICS for both acoustic insulation and acoustic conditioning solutions. All our products have been tested by specialized laboratories to certify their acoustic quality.

CASE STUDIES

Our acoustic engineers have advised our customers on numerous projects in the field of acoustics. Here are some of them, as a sample of the multiple actions that can be carried out with our fabrics.

More about acoustic insulation and acoustic conditioning

  1. WHICH FABRIC DO I NEED?

    At TEXTIL BATAVIA we have a wide range of acoustic fabrics that allow us to adapt to any need. All our fabrics have been tested according to international standards to know in detail their acoustic properties and thus be able to guarantee their performance.
    To choose which fabric best suits your needs, the first step is to identify what your circumstances are.
    If the enclosure or room where you want to place the fabric has any of these problems:

    – Noise produced by the movement of the neighbours -children running, heels, etc.
    – Noise from the premises located on the ground floor of the building – bars, pubs, cafes, etc.
    – Noise from the terrace of a bar.
    – Noise from traffic.
    – Noise from the mechanical door of a garage.
    – Noise from the lift of the building.
    – Noise from the neighbour’s television.

    Then you need a fabric suitable for acoustic insulation. To find out more about acoustic insulation, see our frequently asked questions about acoustic insulation.

    On the other hand, if the room where you want to install the fabric produces noise at the slightest activity, whether it is listening to music, watching television, playing a musical instrument or even having conversations, then you need a fabric suitable for acoustic conditioning. To find out more about acoustic conditioning, please consult our frequently asked questions about acoustic conditioning.
    However, if you have any doubts, do not hesitate to contact us and any of our acoustic engineers will guide you with no obligation.

  2. What do the acoustic conditioning parameters in the catalogue mean?

    tabla parametros acondicionamiento acustico

    Both the graph on the left and the tables on the right provide information on the absorption coefficient of the curtain.

  3. What is the absorption coefficient?

    The absorption coefficient is a dimensionless parameter that has a value between 0 and 1 and indicates the percentage of sound absorption that a material possesses. Thus, a value of 0.6 of the absorption coefficient indicates that, globally, this material absorbs 60% of the sound waves that hit its surface.

  4. What is the absorption coefficient for?

    The absorption coefficient is used to provide information on the degree of absorption of a material, and thus to design solutions to deal with reverberation problems.

  5. What is reverberation?

    You have probably been to a bar or restaurant where the noise generated by the diners talking prevented you from having a normal conversation, even having problems understanding your interlocutor and sometimes having to raise your voice to make yourself heard.
    These problems are quite common and are not only limited to areas used for hospitality, but can also appear in all types of areas with reflective surfaces -mirrors, glass, polished floors and walls, etc.- or with open spaces inside -minimalist architecture-.
    These areas have problems due to an excess of reverberation.
    These rooms have problems due to excessive reverberation.

  6. Why is reverberation generated in a room?

    All sound is made up of sound waves. When sound is emitted inside an enclosure, whether it is generated by diners in a bar or other sources (loudspeakers, television, etc.), the sound waves that make up that sound propagate through the air particles inside the enclosure.

    When the propagated sound waves meet a surface, a double phenomenon occurs: a fraction of the sound waves is absorbed inside the wall and the rest is reflected.

    Depending on the degree to which the walls absorb the sound waves, we can speak of absorbent or reflective materials. Absorbent materials are those that absorb most of the sound waves that hit their surface. Reflective materials, on the other hand, absorb little of the sound waves. If an enclosure is made of reflective materials – glass, mirrors, polished surfaces – the sound waves generated inside the enclosure will be reflected excessively, producing reverberation: at the slightest activity inside the enclosure, a sensation of amplified sound will be generated, like the bustle generated by diners in a bar.

  7. How is the reverberation of a room measured?

    The reverberation of an enclosure is measured from its reverberation time: the time that a sound is maintained in a room after the sound stops being emitted. In other words: the time that elapses since a sound source stops emitting and the sound it generates stops being heard. The higher the value of this time, the greater the reverberation in a room.

  8. What is the relationship between the reverberation time of a room and the absorption coefficient?

    There is a direct relationship between the absorption of the materials that make up a room and its reverberation time. When there are many absorbent materials, the reverberation time is low. On the other hand, if reflective materials predominate, the reverberation time will be high, producing noise when there is activity.

    Knowing the absorption of the materials is therefore the first step in being able to control the reverberation of a room.

  9. How is the absorption coefficient of a material obtained?

    The only way to obtain the absorption coefficient of a material is from a test. The tests to obtain the absorption coefficient of any material are carried out in accordance with the specifications established in the international standard UNE-EN ISO 354. This standard establishes the test methodology to obtain the absorption coefficient of a material, indicating the degree to which it can reduce the existing reverberation in the room where it is to be installed.
    The absorption coefficient tests of this standard are carried out in standardised reverberation chambers. These chambers are closed rooms with high reverberation – reverberation times greater than 10 seconds – in which the reverberation time of the empty room is first measured using an omnidirectional loudspeaker to emit the noise and, subsequently, a measurement of the reverberation time is made with the curtains installed inside the room. From the results of both situations, the curtain absorption coefficient – the noise absorbed by the curtains – is obtained.

    Furthermore, to ensure that the measurements are reliable, the curtains tested must be between 10 and 12 m2.

  10. How do I interpret the catalogue parameters?

    1-Frequency absorption coefficient values:

    What is frequency?
    If we take a musical instrument, for example, a guitar, when one of its strings is plucked, it generates a sound -a musical note-. To produce the musical note, the plucked string vibrates about its initial position. Frequency is measured in Hertz (Hz) and is defined as the number of times per second the string vibrates. Thus, when you tune your guitar, you are adjusting the tension of the string so that it vibrates at the desired frequency when plucked. For example, the note LA is tuned to 440Hz, so that each time this note is pressed, the string that generates it vibrates at a rate of 440 times per second.

    As sounds are made up of frequencies and the human ear does not perceive all frequencies in the same way, the UNE-EN ISO 354 standard -and in general all standards related to acoustic conditioning- establishes the frequencies at which the results must be presented, as they are considered the most representative. These frequencies are 125, 250, 500, 500, 1000, 2000 and 4000Hz. For each of these frequencies, the average value of the absorption coefficient obtained from the averaging of the frequencies adjacent to them is given. At the frequency of 4000Hz, for example, the tested acoustic curtain has an absorption coefficient of 0.76. This means that for all sound waves with a frequency of 4000Hz, the acoustic curtain will absorb 76% of them.

    2-Global absorption coefficient values:

    The second table indicates different parameters of the global absorption coefficient. That is, the absorption coefficient of these parameters is obtained by averaging the absorption coefficient of various frequencies. The differences in the results of these parameters are due to the frequencies chosen for the averaging:

    The parameter is not indicated since it is not obtained by averaging, but by comparing the values obtained with reference values. The calculations are too complex to be given in this catalogue. However, the results are often similar to those of the αw parameter. These two parameters are the most commonly used in room acoustics as they are considered to be the most representative.

  11. What do the sound insulation parameters in the catalogue mean?

    In the technical characteristics of our curtains we can find the following information:

    Both the graph on the left and the tables provide information on the level of acoustic insulation of the curtain.

  12. What is acoustic insulation?

    Regardless of whether you live in a big city or in a village, in a single-family home or in a block of flats, it is very likely that you have had problems with noise generated outside your home, such as that described in the following situations:

    – Noise produced by neighbours walking -children running, heels, etc.-
    – Noise from neighbours’ cisterns.
    – Noise from premises located on the commercial ground floor of the building -bars, pubs, cafés, etc.-.
    – Noise from the terrace of a bar.
    – Noise from an air conditioning unit in another dwelling.
    – Noise from traffic.
    – Noise from the mechanical door of a garage.
    – Noise from the building’s lift.
    – Noise from the neighbour’s television.
    – Noise from the neighbour’s television.

    These problems are not exclusive to private homes, but also occur in other environments that we frequent regularly, such as the workplace.
    Acoustic insulation can be defined as the set of acoustic solutions that are used in enclosures that have problems such as those described above. These solutions range from construction elements – walls and floors made with acoustic insulation – to other technical elements such as acoustic curtains and their objective is to prevent noise from outside from filtering into a room.

  13. How is sound insulation measured?

    To measure the sound insulation of a material – such as acoustic curtains or building materials – the sound reduction index (R) is used. This index can be defined as the difference between the sound pressure level inside the room and the sound pressure level outside the room. In other words, the noise level that the material can reduce, expressed in decibels.

  14. What is the noise reduction index for?

    The sound reduction index is used to obtain the sound insulation level of a material. Thus, knowing this value, we can calculate the noise level that a material will be able to reduce when installed and know in advance if it will serve to reduce the noise coming from outside.

  15. How is the sound reduction index obtained?

    The only way to obtain the sound reduction index of a material is from standardised tests. The tests to obtain the acoustic reduction index of any material are carried out in accordance with the specifications established in the international standard UNE-EN ISO 10140-2. This standard establishes the test methodology to obtain the acoustic reduction index of a material, indicating the degree to which it can reduce the noise coming from outside the enclosure where it is to be installed.

    The acoustic reduction index tests of this standard are carried out in standardised transmission chambers. These chambers are composed of two adjoining enclosures separated only by a partition surface where the sample to be tested is placed. For the test, noise is emitted in an omnidirectional loudspeaker in one of the enclosures (transmitting enclosure) and measurements are made of the noise reaching the other enclosure (receiving enclosure). From the difference between the noise emitted and the noise received at the receiver, the noise level that the material under test is capable of reducing is obtained.

  16. How do I interpret the catalogue parameters?

    In the catalogue we have two tables:

    1-Value of the acoustic reduction index by frequencies R:
    What is frequency?
    If we take a musical instrument, for example, a guitar, when we pluck one of its strings, it generates a sound -a musical note-. To produce the musical note, the plucked string vibrates about its initial position. Frequency is measured in Hertz (Hz) and is defined as the number of times per second the string vibrates. Thus, when you tune your guitar, you are adjusting the tension of the string so that it vibrates at the desired frequency when plucked. For example, the note LA is tuned to 440Hz, so that each time this note is pressed, the string that generates it vibrates at a rate of 440 times per second.

    As sounds are made up of frequencies and the human ear does not perceive all frequencies in the same way, the UNE-EN ISO 10140-2 standard – and in general all standards related to acoustic insulation – establishes the frequencies at which the results should be presented, as they are considered the most representative. These frequencies are 100, 125, 160, 200, 250, 250, 315, 400, 500, 630, 800, 1000, 1250, 1600, 2000, 2500, 3150Hz. For each of these frequencies, the averaged value of the acoustic reduction index obtained from the averaging of the frequencies adjacent to them is given. At the 2500Hz frequency, for example, the tested acoustic curtain has a sound insulation index of 19.6dB. This means that for all sound waves with a frequency of 4000Hz, the acoustic curtain will reduce the sound pressure generated by them by 19.6dB.

    2-Global Rw value
    This is the global value in decibels obtained from the values of the acoustic reduction index by frequencies explained in the previous section.

    What is a decibel (dB)?

    The decibel is a unit of measurement widely used in telecommunications to express quantities of other units on a logarithmic scale. Thus, the word decibel can refer to several concepts. In the field of acoustics, decibels are used to measure both sound pressure and sound power.

    To better understand what decibels are, let’s look at the following example:
    Sound can be generally defined as the physical phenomenon that occurs when an emitting body vibrates in a medium. When we speak, for example, a vibration is produced in our vocal cords, generating a sound wave.

    As our vocal cords are in contact with the air – the medium – the wave generated creates pressure variations in the air, causing the particles that form it to vibrate. Thus, the air particles oscillate around their normal position, transmit the vibration to their neighbouring particles and then return to their initial position. In this way the sound wave propagates through the air particles at a speed that depends on the density and elasticity of the medium – approximately 340m/s in air.

    When the wave reaches the receiver, it enters the ear and impacts with the eardrum membrane. The impact of the wave is received in the form of a nerve stimulus that the brain decodes as sound.

    The discomfort that these sound waves cause us is equated with the pressure they exert on the membrane of our ears and corresponds to what is colloquially known as the volume at which they are heard. The volume, therefore, can be equated with the pressure that the sound waves exert on the medium.

    Sound level meters are used to normalise and measure sound pressure, the operation of which is inspired by that of the human ear. A sound level meter contains a microphone made up of a membrane that receives the pressure that sound waves exert on its surface when they hit it. From a transducer, the value of the pressure exerted is obtained.
    Sound pressure is measured in Pascal (P), after Pascal. However, in practice, the measurement in Pascals is converted to a logarithmic scale to normalise its value and is called sound pressure level, measured in decibels.

    To normalise the decibel value, the following formula is used:

    Lp = 20xlog (P / Pref)

    Where Lp is the sound pressure level, i.e. the pressure value measured in decibels.
    P is the pressure realised by the sound wave.
    Pref is the reference value by which the measured sound pressure is normalised. It has a constant value of 2×10-5P.

    Observing the expression we see that it contains units of pressure in both the numerator and the denominator, the result being dimensionless. Therefore, the result is only expressed in dB (decibels) and not in decibels Pascal (dBP). In other fields of telecommunications, units of dB (decibels) are used.