Discover the difference between acoustic isolation and conditioning

In the acoustics industry, it is crucial to tell the difference between acoustic isolation and sound conditioning, because both of them play fundamental but different roles in the management of an acoustic space. In today’s article, we explain this in detail with the help of our experts in acoustic quality. Read on!

Acoustic isolation: Definition

Acoustic isolation is the combination of engineering techniques and the correct use of different materials with the goal of minimizing the transmission of outside sound, music, noise or vibration to the inside of a building, or from within a building itself to the inside of a specific room, be it either through the walls, ceiling, floor or ventilation pipes. When soundwaves make contact with a structural element, part of the energy is reflected outwards and the rest of it is absorbed, depending on the used materials. The measuring unit in this procedure is the decibel (dB).

Sound transmission between two spaces in a building occurs through different paths:

• Direct transmission: Airborne sound strikes a surface in the room, causing it to vibrate. This is known as the “drum effect.”
• Indirect transmission: Occurs when sound propagates through adjacent surfaces, affecting other walls, ceilings, or floors.
• Structure-borne impact transmission: Generated by activities that directly impact the building structure, such as footsteps, the use of household appliances, or air conditioning systems.
• Residual transmission: Through openings such as ventilation ducts, shutter boxes, or gaps in doors and windows.

For more detailed information on this topic, you can expand your knowledge through the following two links:

• Basic Document HR – Protection against noise
• DB-HR Application Guide: Chapter 2.1 Sound Insulation DB HR

To improve sound insulation, several actions can be carried out, such as repairing or replacing deteriorated windows, improving wall assemblies, or installing acoustic window and door systems. In cases with higher performance requirements, it is possible to build a fully decoupled room with a floating structure that minimizes the transmission of vibrations.

You can find more information through these links:

• What is the best material for soundproofing? Our recommendation
• How to soundproof a rehearsal room?

Contact us. We are an acoustic consultancy, so the first thing we will do is assess whether acoustic measurements are required to determine whether you comply with local regulations. This way, the sound insulation will be properly designed—neither overdone nor insufficient—ensuring that your building can safely support the additional load of a construction solution tailored to your specific case. 

Acoustic conditioning: Meaning

Acoustic treatment refers to improving the acoustic comfort within a room, aiming to increase speech intelligibility in classrooms or meeting rooms, or to enhance the quality of music reproduction. The goal is to achieve a balanced listening environment, where all frequencies are perceived naturally and without distortion.

To evaluate acoustic treatment, we calculate or measure the reverberation time, which is the period in seconds it takes for the original sound to decrease in intensity by 60 dB, according to W.C. Sabine (RT60).

Recommendations for acoustic treatment vary depending on the use and other characteristics of the space:

• Common areas in educational, public residential, and hospital buildings: Acoustic treatment in m² = 0.2 × volume of the space in m³.
• Classrooms and conference rooms with a volume of 350 m³ or less: Reverberation time ≤ 0.7 seconds.
• Dining areas and restaurants of any size: Reverberation time ≤ 0.9 seconds.

Note: You can find this information and other useful details, such as how to calculate reverberation time, in the Acoustic Treatment Guide of the Technical Building Code.

• Music rooms: 10% of the total surface area of walls and ceiling covered with absorbent material for acceptable listening.
• Rehearsal or recording rooms: 20%–40% of the total surface area of walls and ceiling covered with absorbent material effective in high, mid, and low frequencies.
• Audiovisual production: 40%–60% of the total surface area of walls and ceiling covered with absorbent material effective in high, mid, and low frequencies.
• Voice recording: 60%–100% of the surfaces covered with absorbent materials (always walls and ceiling). For the floor, it is recommended to avoid full carpeting or similar coverings, using them only occasionally for decorative purposes.

There is a variety of specialized software available to calculate the RT of a room based on the materials used in its walls, ceiling, and floor, using the acoustic absorption values of each material tested in a laboratory. There are listings with these absorption data (wood, different types of flooring, ceramic brick finished with plaster, concrete, etc.). Using the absorption data of absorbent panels or bass traps, it is possible to simulate the RT of the room under study.

The closer the absorption value is to 1, the more absorbent the material is. If you look at the absorption table of Auralex products, you will see that at mid and high frequencies, almost all panels are sound-absorbing. Different types of absorbents will need to be combined to also reduce reverberation at low frequencies.

Differences between Sound Isolation and Acoustic Conditioning

Although both concepts are related, their goals and methods are different:

Acoustic Isolation:

• Prevents transmission of sound from one space to another one.
• Utilizes dense materials and structural detachment methods.
• It is essential to comply with local regulations and avoid noise problems for neighbors.

Acoustic Conditioning:

• Improves the quality of sound within a space.
• Utilizes light and porous materials that absorb the sound.
• It focuses on achieving adequate reverberation time for the intended use of the space.

An acoustically isolated space tends to have greater reverberation because sound cannot exit the room and remains inside that space. That is why it is common to need extra acoustic conditioning in rehearsal or musical production spaces.

Here at Mas Acoustics we are experts in acoustic conditioning for TV sets, recording studios and many different types of workplaces of the audiovisual sector.

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Why is acoustic treatment important?

Acoustic treatment is fundamental for various purposes:

• Education: In classrooms or meeting rooms, it improves the intelligibility of speech, easing the process of learning and communicating.
• Music and audiovisual production: It ensures that recordings and plays are of the highest quality, with an organic and balanced sound.
• Amusement and work spaces: In offices, restaurants and other public spaces, it reduces the background noise and improves the acoustic comfort, creating nicer and more productive environments.

In summary, while acoustic isolation is fundamental to control the transmission of sound between spaces, acoustic conditioning is vital to guaranteeing an optimal auditory experience inside any kind of space. Both aspects must be carefully considered during the design and construction of any space that requires effective acoustic care.

For any other questions, feel free to contact us and receive personalized guidance.