While the terms “sound absorption” and “soundproofing” are often used interchangeably, they refer to products with distinct purposes. As such, it is essential to understand the differences between the two terms to ensure you select the right type of noise reduction product for your application.
In this blog post, we explore the differences between sound absorption and soundproofing products, explaining what they do, how they function, and what applications for which they are suited to help guide the selection process.
What Is Sound Absorption?
Although sound waves weaken as they travel farther from their source, they can seem louder or more bothersome if given a chance to echo. For this reason, acoustic absorption products are designed to reduce perceived noise levels by eliminating the reflection of and increasing the distance traveled by sound waves. One important thing to note is that they only improve the acoustic properties within the space. They do not block sound from entering or leaving a space.
Acoustic absorbers are generally made from softer materials with open-celled structures, such as foams or fiber-based substrates. The numerous holes within the material make it easy for sound waves to enter but not to exit, essentially trapping—i.e., absorbing—them. Each sound absorber is given a Noise Reduction Coefficient (NRC) rating that describes how much sound they can absorb.
What Is Soundproofing?
Soundproofing prevents sound waves from traveling through a surface, which stops them from escaping or entering a space. As a result, soundproofed machines in operation emit less noise.
Soundproofing represents the common conception of sound blocking. Acoustic barriers often referred to as soundproofing materials, are generally found within engine enclosures or compartments incorporated by OEMs during initial designs. Acoustic barriers are made from denser substrates than those of acoustic absorbers, which serve as a barrier against the sound waves between the source of the noise and the “quiet” area(s). They are given a Sound Transmission Class (STC) rating, which describes how well the barrier attenuates sound.
Applications for Sound Absorption and Soundproofing Products
Since sound absorption and soundproofing products serve different noise reduction purposes (absorbing and blocking), they are suitable for different noise reduction applications. For example, sound absorption products—such as acoustic absorbers—are used in equipment enclosures and operator cabs, while soundproofing products—such as acoustic barriers—are utilized for engine housings, heavy equipment and vehicle floor mats, and firewalls. However, some applications may require both sound absorption and soundproofing products to achieve optimal acoustic properties.
Contact the Noise Reduction Experts at Technicon Acoustics Today
Some companies find it challenging to determine whether sound absorption or sound barrier materials are right for their needs. Fortunately, the experts at Technicon Acoustics are here to help.
We are the leading producer of acoustic solutions for original equipment manufacturers (OEMs) in North America. Equipped with over 40 years of industry experience, we can design, develop, and deliver products for nearly any sound absorption, blocking, or isolation need.
Commercial power generators, air compressors, and other industrial equipment make a lot of noise. To counter loud noise levels, OEMs attempt to contain the disruptive sounds with an enclosure.
Enclosures are supposed to trap sound waves so they don’t affect the ambient environment. Unfortunately, most traditional sound enclosures are less effective than the industry commonly thinks. Without the right acoustic lining, enclosures only block a fraction of the sound waves. Even worse, improperly lined enclosures can actually amplify noise, before it can reduce it.
Sheet-Metal Sound Enclosures Are Not Enough—Here’s Why
Most sound enclosures are made from sheet metal. This type of solid barrier can deflect sound waves to some degree, but it has a limited impact.
To find a better solution, our team of engineers at Technicon Acoustics investigated how sound enclosures performed with and without acoustic-absorber lining materials. Using a device that outputs a constant sound at 85 decibels, we tested the decibel level one meter away from the sheet-metal enclosure and discovered the volume rose internally to 113 decibels—a net increase of 28 decibels compared to the sound origin.
Why did sheet-metal enclosures make the environment 28 decibels louder? With further testing, we determined the solid barrier did obstruct sound waves upon contact, making the noise softer—however, the sound was amplified inside of the enclosure before it transferred into the surrounding area.
Ultimately, our study reveals manufacturers must pay attention to two factors: the material of the physical barrier and the subsequent sound wave concentration inside the enclosure. The enclosure can reduce noise, but OEMs are not reaping the full benefits of an enclosure without using acoustic absorber material internally.
How Can Modified Sound Enclosures Reduce Noise?
We theorized the right acoustic-absorber lining material and design could manage air paths and reduce a device’s sound output more effectively. To test our theory, we used an enclosure with a 24-inch-by-36-inch louver and discovered the following decibel changes:
- Acoustic Barriers: -4.1 decibels
- 1-inch Absorber Foam: -7.0 decibels
- 2-inch Absorber Foam: -8.5 decibels
Contact the Technicon Acoustics Team Today to Get Started
To prevent these problems and soften loud noises, we recommend using acoustic absorber foams in an enclosure to block and absorb sound for a net decibel reduction. Contact Technicon Acoustics today to learn more about our sound absorber tools specially engineered for power generation equipment, air compressors, and commercial machinery.
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For acoustic and thermal insulation applications, one of the most commonly utilized materials is melamine foam insulation. While it demonstrates adequate sound absorption and thermal insulation characteristics, there is an alternative material solution that offers more effective and efficient performance for original equipment manufacturer (OEM) needs—polyester fiber insulation.
The following blog post provides a comparison between polyester fiber and melamine foam to outline which material option is better for acoustic and thermal insulation applications.
Polyester Fiber vs. Melamine Foam
Compared to melamine foam, polyester fiber offers a number of advantages that make it more suitable for use as acoustic and thermal insulation, such as:
- Greater durability. Polyester fiber is much more durable than melamine foam. It maintains its shape and structural integrity after exposure to most chemicals, fuels, and oils—as well as water, ultraviolet (UV) radiation, and ozone—without requiring the addition of specialty coatings or finishes. In contrast, melamine foam needs extra processing to achieve similar hydrophobicity and other surface characteristics.
- Higher flexibility. Both polyester fiber and melamine foam demonstrate a high degree of flexibility. However, polyester fiber demonstrates better flexibility than melamine foam, which makes insulation made from it easier to incorporate into compact spaces.
- Better handleability. As indicated above, polyester fiber is easier to work with than melamine foam. This quality is due largely to the material’s durability and flexibility, which allow it to remain intact even when bent or dropped. In contrast, melamine foam—when mishandled—may snap if sufficient force is applied to it.
- Lower cost. Melamine foam comes with a high price tag, especially if special coatings are required to make it suitable for use in specific environments. In contrast, polyester fiber has a lower manufacturing cost, which, in turn, results in a lower purchasing cost. As such, OEMs can invest in low-cost material without sacrificing insulation quality.
Why Choose Polyester Fiber From Technicon Acoustics?
As outlined above, polyester fiber exhibits many qualities that make it ideal for acoustic and thermal insulation applications. However, benefiting from these material qualities necessitates choosing high-quality material from a reputable supplier.
At Technicon Acoustics, we offer a proprietary fiber blend that demonstrates exceptional sound absorption and thermal insulation properties. It is a non-toxic material characterized by excellent low-frequency absorption and high-temperature resistance (up to 350 degrees Fahrenheit). Additionally, as it is made from a combination of virgin fiber and pre-consumer and post-consumer waste, it is highly recyclable, making it a much more environmentally alternative to other insulation options. The material is also UL94 HF1 listed and complies with Docket 90 Testing standards for flame, smoke, and toxicity (ASTM E162, ASTM E662, and BSS7238).
All of our materials are highly customizable. The polyester fiber is available in several thicknesses (ranging 0.5 to 2.0 inches) with options for cut pieces (for ease of use) and adhesive backing (for ease of installation).