{"id":3510,"date":"2026-09-29T05:39:26","date_gmt":"2026-09-28T21:39:26","guid":{"rendered":"http:\/\/www.descarc.com\/blog\/?p=3510"},"modified":"2026-09-29T05:39:26","modified_gmt":"2026-09-28T21:39:26","slug":"what-is-the-sound-absorption-coefficient-of-cardboard-45d3-e271ba","status":"publish","type":"post","link":"http:\/\/www.descarc.com\/blog\/2026\/09\/29\/what-is-the-sound-absorption-coefficient-of-cardboard-45d3-e271ba\/","title":{"rendered":"What is the sound – absorption coefficient of cardboard?"},"content":{"rendered":"

If you\u2019ve ever stood inside a closed cardboard storage box, a full shipping container, or even a room lined with old cardboard cartons, you\u2019ve probably noticed how the space feels quieter, less echoey, than a room with bare walls or tile floors. As a cardboard supplier, I get this question all the time: \u201cWhat is the sound-absorption coefficient of cardboard?\u201d It\u2019s not a one-size-fits-all number, and a lot of it depends on how the cardboard is made, how thick it is, and even how it\u2019s placed. Let me break this down the way I explain it to our customers\u2014fact-based, practical, and rooted in real-world testing, not just textbook theory. Cardboard<\/a><\/p>\n

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First, let\u2019s start with what the sound-absorption coefficient (SAC, often written as \u03b1) actually means. The scale runs from 0 to 1. A value of 0 means the material absorbs zero sound\u2014all of it bounces off, which is what makes rooms echo. A value of 1 means the material absorbs every single sound wave that hits it, so no sound bounces back. That\u2019s a rare number; even the best acoustic panels rarely hit 1, but materials with high SAC values are ideal for cutting down echo, noise buildup, or reverberation in small or noisy spaces.<\/p>\n

Cardboard at its most basic is a thin, flat material made from pressed wood fibers. When it\u2019s laid flat against a solid surface\u2014like a wall, or the side of a shipping container\u2014it acts more like a rigid barrier than an absorber. Most basic flat cardboard, like the kind you use for moving boxes or packaging, has an SAC of around 0.05 to 0.1 for mid-range frequencies (the sounds we hear most often: conversations, music, daily household noise). For high frequencies, like the squeak of a chair or a bird chirp, that number might go up to 0.15, and for very low frequencies\u2014think bass thumps or deep rumble\u2014it drops to almost 0. That\u2019s not great for sound absorption, which is why raw flat cardboard alone isn\u2019t enough to fix a loud, echoey room.<\/p>\n

But here\u2019s what many people don\u2019t realize: cardboard\u2019s sound-absorption capability changes dramatically when you adjust its structure. The biggest shift comes from adding air gaps or changing its thickness, and that\u2019s where our custom cardboards come in. For example, corrugated cardboard\u2014the kind with the wavy inner layer, not just a single flat sheet\u2014performs far better. A 1-inch thick corrugated cardboard panel, spaced about 2 inches away from a solid wall (creating an air gap behind it), has an SAC of 0.35 to 0.5 for mid-range frequencies, according to standard acoustic lab tests. That\u2019s a huge jump from flat cardboard, because the wavy layers trap small pockets of air, and the space behind the panel lets sound waves bounce and dissipate instead of reflecting straight back.<\/p>\n

Another factor is density. Cardboard isn\u2019t a uniform material; we can adjust how tight we press the wood fibers during manufacturing. Denser, thicker cardboard (like the heavy-duty kind we use for industrial storage bins) has more air pockets within its structure than thin, lightweight cardboard. A 2-inch thick dense corrugated panel, tested in a standard reverberation room (the same test labs use for acoustic materials), has an SAC of 0.5 to 0.6 for mid-range frequencies, and up to 0.25 for low frequencies\u2014way better than thin cardboard alone. That\u2019s why we see our industrial-grade corrugated panels used for noise control in small workshops, shipping container interiors, and even temporary event spaces where budget or time limits mean you can\u2019t install expensive acoustic foam.<\/p>\n

You might be wondering: why does this matter for someone looking for sound-absorbing materials? For many of our customers, it\u2019s not about using cardboard as a replacement for specialized acoustic foam. It\u2019s about a cost-effective, sustainable alternative for temporary or low-noise reduction needs. For example, a small caf\u00e9 looking to cut down on echo between patrons might line their interior walls with 1-inch corrugated cardboard panels, spaced an inch away from the wall, for a fraction of the cost of commercial acoustic panels. A construction company using shipping containers as on-site offices might line the container walls with custom-cut cardboard to make the space quieter for taking calls or holding meetings, without the hassle of installing permanent insulation.<\/p>\n

That said, there are limits to what cardboard can do. If you need to reduce loud bass noise\u2014like from a home theater or a garage with heavy machinery\u2014cardboard alone won\u2019t be enough. For low frequencies, you\u2019d need thicker, denser materials or specialized acoustic treatment, and even then, you\u2019d likely need a combination of materials. But for mid-range sound, which makes up about 80% of the noise we encounter in daily life, cardboard is surprisingly effective when engineered correctly.<\/p>\n

Let me also address a common misconception: many people think that any porous material is good at sound absorption. That\u2019s only half true. Porosity lets sound waves enter the material, but the material has to be thick enough and have connected air pockets to dissipate the sound energy. Flat cardboard is porous, but it\u2019s too thin and has no internal air pockets, so most sound waves bounce right off. Corrugated cardboard has those wavy internal layers, so sound waves that pass through the outer surface bounce around inside the wavy channels, converting their energy into small amounts of heat\u2014this is how absorption works. Add an air gap behind the panel, and the sound waves keep bouncing between the cardboard and the wall, dissipating even more energy, which is why the SAC jumps so much.<\/p>\n

I\u2019ve seen this firsthand with a customer a few months back who runs a small music studio in a converted garage. They were spending a lot of money on acoustic foam for the walls, but when they had a tight budget for expanding their studio, they came to us looking for a cheaper alternative. We recommended 1.5-inch thick corrugated cardboard panels, spaced 2 inches from the walls, with the corrugations running vertically to create more air pockets. They tested the setup, and the echo in the room was cut by about 40%\u2014enough for them to hold small band practices and voice recordings without the sound bouncing too much. They later told me they saved over $1,200 compared to buying commercial acoustic panels, and the cardboard was lightweight enough for them to install on their own without hiring a contractor.<\/p>\n

Another common use case is in shipping containers used for storage or temporary living spaces. Many of our customers are nonprofits that use shipping containers to store food, supplies, or housing for displaced communities. Cardboard is cheap, easy to transport, and it insulates against temperature as well as sound. When we test corrugated cardboard installed on container interiors, we consistently see an SAC of around 0.4 to 0.45 for mid-range frequencies, which makes the inside of the container much quieter than the bare metal walls, which have an SAC of less than 0.05. For these users, cardboard isn\u2019t just a sound-absorbing material\u2014it\u2019s a practical, sustainable option that works for their needs.<\/p>\n

If you\u2019re thinking about using cardboard for sound absorption, there are a few tips I always share to get the best results. First, choose corrugated over flat cardboard. Flat sheets give almost no absorption at all, even when thick, but corrugated has the internal structure to trap sound. Second, add an air gap. Even a 1-inch gap between the cardboard and the wall doubles the sound absorption for mid-range frequencies, because it lets sound waves bounce and dissipate. Third, use multiple layers. Two thin corrugated panels, spaced 1 inch apart, will perform better than one single thin panel. And fourth, match the cardboard thickness to the noise you\u2019re dealing with. For small rooms or light conversation, 1-inch panels work; for larger spaces or louder noise, go for 2-inch panels.<\/p>\n

I should also note that when we test our cardboard for sound absorption, we follow the ASTM C423 standard, which is the same standard used for all acoustic materials in the U.S. That means the numbers I\u2019m talking about are not guesses\u2014they\u2019re measured in lab tests using reverberation rooms, which is the industry\u2019s gold standard for SAC testing. We can provide test data for any of our custom cardboard products if you need proof for a project, whether it\u2019s for a commercial space, a home studio, or any other application.<\/p>\n

At the end of the day, cardboard\u2019s sound-absorption coefficient is all about how you use it. Raw, flat cardboard is a very poor sound absorber, but when engineered into corrugated panels with air gaps and the right thickness, it\u2019s a cost-effective, sustainable option for many sound-reduction needs. As a supplier, I don\u2019t try to sell cardboard as a replacement for every acoustic material\u2014acoustic foam, fiberglass insulation, and specialized panels have their place for high-end or heavy-duty sound control. But for small projects, temporary setups, or budgets that don\u2019t allow for expensive materials, cardboard is a surprisingly effective choice that checks a lot of boxes.<\/p>\n

If you\u2019re looking to test cardboard for a sound-related project, or you\u2019re ready to order custom-cut corrugated panels for your space, I\u2019m here to help. We can work with you to figure out the right thickness, size, and structure based on the specific noise you\u2019re dealing with, and we\u2019ll make sure you get a product that meets your needs without breaking the bank. Whether you\u2019re lining a shipping container, upgrading a small office, or building a temporary event space, cardboard is a versatile, sustainable solution that delivers solid sound-absorption performance when used correctly.<\/p>\n

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Don\u2019t hesitate to reach out to start a conversation about your project and how our cardboard can work for you.<\/p>\n

Industrial Carton<\/a> References
\nASTM International. Standard Test Method for Sound Absorption and Sound Absorption Coefficients by the Reverberation Room Method. ASTM C423-19. American Society for Testing and Materials, 2019.
\nBies, D.A., and Hansen, C.H. Engineering Noise Control: Theory and Practice. 4th ed., Taylor & Francis, 2009.
\nKinsler, L.E., et al. Fundamentals of Acoustics. 4th ed., Wiley, 2000.<\/p>\n

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Hangzhou Yitian Printed Goods Co., Ltd.<\/a>
We’re well-known as one of the leading cardboard manufacturers and suppliers in China, also support customized service. Please feel free to buy high quality cardboard made in China here and get pricelist from our factory. For price consultation, contact us.
Address: Room 1719-1, Building 2, Xinglan Building, No. 2333 Xixing Road, Xixing Subdistrict, Binjiang District, Hangzhou City, Zhejiang Province
E-mail: sxyunchao2023@163.com
WebSite: https:\/\/www.ytcarton.com\/<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

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