We improve the comfort and acoustic quality of any space where many people congregate, such as restaurants, classrooms, conference rooms, sports centers, theaters and auditoriums.

As part of the scope of our work, we advise on the verification of the geometry of the rooms (size, volume and shape), as well as on the choice of materials.

Soundproofing and vibration control
Acoustic conditioning in leisure rooms Andalucia
Acoustic adaptation of spaces
Acoustic adaptation of spaces
Acoustic conditioning

Acoustic behavior analysis

Our technical advice allows us to reduce the risk regarding the expected results of the acoustics of the room, given that despite the subjectivity and emotionality of the sound, there is a series of quantifiable physical parameters by way of computer simulation that allow us to evaluate the foreseeable behavior of the rooms. themselves.

These fundamental parameters for analyzing the acoustic behavior of the enclosures arethe following:

  • Impulse Response Analysis: Reflections or echoes.
  • Analysis of reverberation times (TR): it is the star parameter when designing an auditorium, and its recommended value is a function of the frequency and the preferential use of the room (there will be significant variations of TR between rooms 162 in which it rewards a very good hearing of the word, such as theaters, compared to others whose use is mainly intended for music, the needs of a room to listen to rock music being very different than a venue whose use is that of a symphony orchestra or the of an opera).
  • Brightness and warmth: these are two parameters defined from the TR and to evaluate the response to bass sounds (a room has acoustic warmth if it has a good response to low frequencies, a smooth and mellow sound).
  • EDT (immediate reverberation time) to evaluate the sound homogeneity of the room.
  • Diffusion of the room: study of the reflections, of the forms of the walls, etc.
  • Definition Index D50, to assess the response in each receptor.
  • Sound Clarity Index C80.
  • Loudness level G, related to the directionality of the sources.
  • STI and RASTI intelligibility index, fundamental in theaters.

Acoustic Simulation Software

Through the use of acoustic simulation software, we will work with full-scale mathematicalmodels that simulate the acoustic behavior of the enclosure and represent the results in the form of color mapping, an easily understandable graphical representation when interpreting results and correcting effects that are not desired. We can even simulate listening to the room by simulating its auralization, but let’s remember that sound is a science with a large part of subjectivity.

Acoustic Engineering Andalucia

Noise absorbing materials

Introduction

Truth be told, all materials can absorb sound energy to some extent. However, materials that are specifically known as sound absorbers or sound absorbers will absorb most of the sound energy that collides with them. These specialized materials are generally referred to as “acoustic materials” and are designed to have high absorption qualities.

The main use of these materials is to reduce reverberant sound pressure levels (the one that originates when the sound wave “bounces” off the surfaces that are in its path). This leads to a reduction in the overall reverberation in a space, commonly (and actually quite imprecisely) known as echo rolloff.

There are various sound-absorbing materials. However, before discussing them, we must first understand the difference between sound absorption and soundproofing.

Soundproofing vs. Acoustic Absorption: What’s the Difference?

When it comes to general acoustics, there may be two different goals:

  1. Absorb the reverberant energy that creates sound within a space.
  2. Avoid transmission of sound energy.

The search for compliance with the first of these objectives is known as acoustic adaptation and that of the second is known as soundproofing/a>. Both forms of sound manipulation use specific materials and products to combat sound waves.

Sound-absorbing materials will absorb most of the sound energy that collides with them and reflect very little. This quality makes them useful in noise control within a space or enclosure.

They are used in a variety of locations: near the source of the noise, in intermediate positions, or near the receivers.

For its part, however, soundproofing a space involves four concepts: adding mass, damping, decoupling, and absorption. In practice, acoustic absorption is a necessary but not sufficient part of reinforcing the acoustic insulation capacity. Materials used for soundproofing are often dense and heavy, allowing them to decouple structures. Thanks to its density, instead of sound waves penetrating through the structure, they are reflected back into space.

Types of noise absorbing materials

Acoustic absorption is the process by which sound energy is dissipated and transformed into another form of energy: heat, mechanical and/or deformation. From a technical point of view, there are three main types of sound absorbers: porous, membrane, and resonance.

There are several materials that absorb sound. Its ability to absorb sound waves is highly dependent on frequency, composition, thickness, and mounting method.

Porous absorbents

Porous absorbentsMaterials with a high acoustic absorption coefficient areusually porous.

Unlike soundproofing materials, sound absorbing materials are not dense, they are permeable. Sound waves penetrate the surface of these materials and flow into the fibrous or cellular structure of which it is composed.

It is important to remember that energy can never be created or destroyed, it can only be transformed. Porous absorbers will convert incident sound energy into thermal energy through frictional and viscous resistance in the fibrous or cellular structure of the material.

The amount of heat generated by sound waves is minimal; less than a millionth of a watt.When porous sound absorbers are used, only a small portion of the sound energy is reflected back into space.

Porous absorbers are most effective for mid-range frequencies or high tones. They tend tohave less effect towards lower frequencies and have minimal effect with bass.

Common examples of porous sound absorbers include mineral wool, carpet, fiberboard,insulation blankets, and certain forms of plastic foam.

Membrane or plate absorbents

Material absorbente placaA membrane or plate absorber is an impermeable, non-rigid, non-porous material that is placed over an air space. When acoustic energy is applied to the absorber, the oscillating system (mass of the front panel and the spring formed by the trapped air) is transformed into mechanical energy.

These materials often have a solid appearance and as such are often overlooked as sound absorbing materials. That said, they are particularly effective against low-range frequencies, such as bass.

They will also reflect higher frequency sounds. It will be necessary to apply other forms of soundproofing and absorption to counteract this added effect.

Common examples of membrane absorbers are wood paneling or hardboard, gypsum suspended ceilings, windows, wood doors, drywall, and wood floors.

Resonators

Materiales resonadoresThese types of sound absorbers are generally only used when you need to combat sound in a narrow but defined frequency range. They are used to focus on issues related to low frequencies.

These types of absorbers work based on acoustic pressure. It is essentially a mass (front wall or diaphragm) vibrating against a spring (the air inside the resonant absorber). By changing the mass or stiffness of the spring, you can adjust the resonant frequency.

They work in a similar way to that of a membrane absorber. Which means they consist of a mechanical oscillation system with a solid plate and a reduced air gap.

An example of a resonance absorber would be a soda bottle. However, a more practical example would be layers of perforated sheetrock or perforated metal.

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