Megasorber 4-fold approach®

Understanding sound and how soundproofing works.

What is NRC?  How is NRC measured?  Why is the frequency of the sound important? What is Rw or STC? How do you achieve superior speech intelligibility and speech privacy?  How do you find an effective solution to various noise issues?

Megasorber’s unique 4-fold approach has all the answers you need:

Understanding noise

How do you measure the loudness of sound? What is the “colour” of the sound?

Decibels—the loudness of noise

Decibels (dB) is a logarithmic, not a linear, unit of measurement for the loudness of sound.

Usually, a change of 1 dB is the smallest volume change detectable by the human ear.  A reduction of 3 dB in noise level is equivalent to about 50% of the sound energy being removed from the system.

Regular exposure to noise at or above 85 dB causes permanent hearing damage.

Frequency – the  “Colour” of noise

The “colour” or “harshness” of the noise is defined by the frequency of the sound.

The sensitivity of human hearing is frequency-dependent. Human ears are most sensitive to sound at around 1,000Hz. Human ears are less sensitive to low-frequency noise such as below 60Hz or extremely high-frequency noise such as above 10,000Hz. As a result, the noise level is adjusted to reflect the sensitivity of the human hearing and the adjusted noise level is termed dB(A), i.e., “A” weighted noise level.

Harsh noise: noise concentrating at around 1,000Hz and higher. This noise frequency tends to cause discomfort to human ears. A typical example is the high pitch noise of vacuum cleaners.

Tonal noise: when one single frequency noise is about 10dB(A) higher than all the other frequency noise. Tonal noise is extremely unpleasant especially exposed over a long period. A typical example is the “humming” noise from a transformer.  Please follow this link to hear the transformer tonal noise and how to tackle the transformer noise.

Occupational Health and Safety (OHS) Requirements

 Occupational Health and Safety Regulations in Victoria, Australia, limit workers’ exposure to 85 dB(A) averaged over 8 hours without wearing hearing protection.

Megasorber Scientific Studies

The research and development of new products and application technologies for acoustic solutions is one of Megasorber’s top priorities. The following studies reflect this commitment to R&D.

Tackling the Strange Wind Noise on a Commercial Building

A mysterious noise was reported in a commercial building. This building has multiple levels of car parks with one single level of office space at the top. This top-level is the head office for Renault Australia, located in Mulgrave, Victoria. The office staff at Renault reported a dreadful “howling” noise around the office. It sounded like a huge convoy of trucks thundering past the office, especially worse on windy days. Specialist engineers, acoustic and wind engineers, were summoned to investigate the root cause of this noise. This case study presents the analysis of the noise, the results of the various tests and the successful practical resolution.

The study is published in the Proceedings of Meetings on Acoustics (POMA).

Download the study

Absorptive Noise Barrier Development

This paper reveals the development of an absorptive, self-supporting noise barrier panel for external applications. Designed for use as a temporary external noise barrier for construction sites and roadside noise barriers. The absorptive noise barrier panel is a module base design that is easy to assemble, disassemble and re-deploy.

The barrier panel utilises recycled plastic materials, such as milk bottles and other soft plastics, making it very environmentally friendly. The barrier is manufactured in one process via a unique rotation moulding method. It is weather-resistant, aesthetically appealing, and offers great design flexibility. Standard size panels are 100mm thick, by 2000m wide x 500mm high.

The acoustic design is modelled to achieve NRC 0.85 at 100mm thick, based on an advanced air-flow resistive layer technique combined with an air cavity. The actual sound absorption measurement results are well in line with the predicted modelling. Such a case study potentially uncovers a whole new range of innovative absorptive noise barriers. Further studies and investigations are also recommended.

Download the study

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