Noise control. An historical excursus
Exposure to high noise levels poses significant risks of permanent hearing loss. Many industries are thus highly motivated to discover cost-effective solutions to address this issue.
The absence of suitable acoustic treatment in industrial setting can, in the best-case scenarios, disrupt the productivity of individuals within these spaces. Even if the noise is not harmful or particularly bothersome, it becomes undesirable when it hinders effective communication among coworkers.
As we have already discussed, much can be done to reduce the seriousness of noise problems. Effective equipment and methods are available for eradicating the noise generated by several engineering systems.
Have you ever considered the origins of these developments? This article offers a comprehensive examination of the historical evolution of industrial soundproofing.
Industrial noise control: historical background
Acoustics, owing to its connection with music, has been a subject of interest for many centuries.
It can be traced back to the Greek philosopher Pythagoras, who conducted early investigations into the physical origins of musical sounds around 550 BC. He observed that when two strings on a musical instrument are plucked, the shorter string produces a higher-pitched sound than the longer one. Notably, if the shorter string’s length is halved compared to the longer one, it emits a note that is one octave higher, signifying a twofold difference in frequency or pitch.
This foundational understanding led to the practice of measuring sound across standard octave bands or frequency ranges encompassing one octave. As a matter of fact, determining the frequency distribution of machinery-generated noise is critical for choosing effective noise control methods.
Credit is generally attributed to the Franciscan friar Marin Mersenne (1588–1648) for the earliest published analysis of string vibration, which he presented in 1636. Mersenne measured the vibrational frequency of an audible tone (84 Hz) produced by a long string. He also noted that the frequency ratio for two musical notes separated by an octave was 2:1.
A well-known scientist has made significant contributions to the field of sound control: in 1638, Galileo Galilei published a treatise on the vibration of strings, in which he established quantitative relationships between the frequency of string vibration, its length, tension, and density. Galileo observed that when different pendulums with varying lengths were set in motion, the resulting oscillations created pleasing patterns if the frequencies of these pendulums had specific ratios, such as 2:1, 3:2, and 5:4, corresponding to the octave, perfect fifth, and major third intervals in music.
In 1713, the English mathematician Brook Taylor, who is also known for developing the Taylor series, mathematically solved the shape of a vibrating string. His equation allowed for the derivation of a formula for the string’s vibration frequency that perfectly matched the experimental findings of Galileo and Mersenne.
In the early stages of acoustics, a precursor to the stethoscope was developed by French physician Rene Laennec in 1819. This device was employed for clinical purposes. In 1827, Sir Charles Wheatstone, a British physicist known for inventing the Wheatstone bridge, created an instrument similar to the stethoscope, which he named a “microphone.”
Following the invention of the triode vacuum tube in 1907 and the initial development of radio broadcasting in the 1920s, electric microphones and loudspeakers became available. These innovations paved the way to produce precise instruments designed to measure sound pressure levels and other acoustic parameters with greater accuracy than the human ear could provide.
Between the 1930s and 1940s, noise control principles started being applied to various areas, including buildings, automobiles, aircraft, and ships. During this time, researchers also began exploring the physical processes involved in sound absorption by porous acoustic materials.
With the outbreak of World War II, there was a renewed focus on addressing speech communication issues in noisy environments, such as tanks and aircraft. In the US, the National Defense Research Committee established two laboratories at Harvard University to tackle these concerns: the Psycho-Acoustic Laboratory studied sound control techniques in combat vehicles, while the Electro-Acoustic Laboratory researched communication equipment for noisy environments and acoustic materials for noise control. After the war, noise control research continued at various universities.
Post-war, noise problems in architecture and industry were finally addressed. Research was directed at solving residential, workplace, and transportation noise issues predominantly. An important development for industrial soundproofing was the 1969 US amendment to the Walsh–Healy Act, which imposed strict limits (e.g., 90 dBA for an 8-hour period) on noise exposure for industrial workers. This law also mandated the provision and training in the use of personal hearing protection devices if the noise exposure couldn’t be prevented.
Contemporary industrial noise control
The 1969 US amendment escalated a series of environmental regulations that were aimed at tackling noise pollution at a global level. Starting from 1970s, industrial facilities around the world were finally required to meet specific noise level standards, driving the need for effective soundproofing solutions.
During this period, industrial soundproofing primarily relied on traditional methods like installing acoustic panels, enclosures, and barriers. These methods were effective but often bulky and expensive. Nevertheless, these are still largely employed nowadays.
The 1980s and 1990s brought advancements in acoustic materials. On the one hand, these decades saw the development of innovative materials that offered better sound absorption and noise isolation properties. Fiberglass, mineral wool, and other materials became popular choices. On the other hand, advancements in manufacturing and construction technologies allowed for more efficient installation of soundproofing solutions. This period also witnessed the introduction of computer simulations for noise control design.
During the 2000s, the focus had been shifted on growing environmental awareness to make soundproofing measures more eco-friendly. Recycled and sustainable materials at this point gained more and more popularity. At the same time, manufactures began offering customized designs to address specific industrial noise challenges effectively.
Stopson Italiana has been an integral part of the industry’s evolutionary journey. With over 56 years of operational history, Stopson Italiana asserts its position as a leading company in the global noise control sector.
Our distinguishing factors include:
- Decades of experience, driving ongoing product enhancement;
- Tireless dedication to advancing technology and competitiveness;
- Profound expertise in soundproofing techniques;
- A track record of overseeing thousands of successful installations in various case studies.
Particularly, Stopson Italiana have become a company of choice when it comes to customizing service and product according to specific customer needs.
Learn more in detail about our soundproofing solutions HERE.