How to soundproof a box? (An Informative Guide)

This blog post will answer the question, “What are the methods to soundproof a box?” principles of soundproofing, what kind of material should be used for effectively soundproofing a box, what are the application of soundproofing a box

How to soundproof a box?

There are several key methods to soundproofing a box

  • Styrofoam or Acoustic Foam Insulation
  • Egg Crate Lining
  • Hardwood Box like OSB, Plywood
  • Acoustic Panels lining
  • Mineral Wool
  • Acoustic Putty
  • Thermal Conversion
  • Constrained Layer Damping 

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Key principles of SoundProofing

The prevention of sound waves passing in or out of a room resulting in acoustic isolation of the designated space is known as soundproofing.

These are fundamental aspects of Sound Proofing:

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Deflection

Deflection of sound waves is achieved by adding dense non porous materials to any structure. This kind of material is very effective at deviating or deflecting noise made through airborne transmission. 

The additional bulk helps to dissipate soundwaves by creating a longer path and therefore higher energy requirement to diffuse into any given space.

However, blocking impact borne transmission is not as effective. It is a higher power, pressure and vibration class than airborne vibration.

Absorption 

Absorption is the phenomena by which sound pressure waves are distributed across a surface with interstitial airspace that prevents transmission through vibration of solid molecules.

Thereby soaking up acoustic energy. Materials such as this  are usually installed in open cavities where the depth of material can be tolerated.

In addition, this kind of material can also prevent additional resonance, reverberation and amplification of sound waves that could be created had the cavity been left empty.

There are 2 types of Absorbers:

Porous absorbers:

Porous open cell foams are highly effective noise absorbers across a broad range of medium-high frequencies. Performance can be less impressive at lower frequencies. The absorption profile is dependent on a number of factors such as:

  • Cell Size
  • Tortuosity
  • Porosity
  • Material Density 
  • Material Thickness

Resonant Absorbers:

Resonant absorbers also called Helmholtz Absorbers work by damping a sound wave while reflecting it. The absorption of a resonant soundwave works only over a low-medium frequency range

Reflection

The comparative distribution of sound pressure variations throughout a given space, or the process by which a soundwave is distributed in the space. If sound pressure is uniformly distributed throughout the space, the sound is said to be well diffused

Diffusion

If a specular reflection from a hard flat surface is giving a problematic echo then an acoustic diffuser may be applied to the surface. It will scatter sound in all directions. This is effective to eliminate pockets of noise in a room.e applied to the surface. It will scatter sound in all directions. This is effective to eliminate pockets of noise in a room.

For more information please visit the following links:

https://www.physicsclassroom.com/class/sound/Lesson-3/Reflection,-Refraction,-and-Diffraction
https://www.acousticalsurfaces.com/blog/acoustics-education/what-is-sound-diffusion-and-absorption/

Decoupling

Decoupling is a method to reduce the area of direct mechanical linkage between structure and substrate. Such as wall and the applied finishing materials.

This process interrupts flanking transmissions that tend to travel through a structures’ own rigidity and connectivity from start to end.

Damping

It is the process of reducing resonance in an enclosed structure by absorption, reflection or diffusion. Absorption will reduce the overall sound level of the structure and redirection reduce the coherence thereby making the unwanted sound harmless.

Distance

The further away an object or a space is from a sound attenuating source the more isolation or blocking it will have from incident sound waves. 

This is because soundwaves lose energy while travelling through any media and therefore dampens by diffusion, reflection & absorption over a finite distance.

Mass

Adding dense material for soundproofing can help reduce transmission by increasing the material molecules present. 

Soundwaves will have to expend more energy through dense substances thereby reducing its impact on the space which requires sound proofing.

Best Materials to Consider when making a Soundproof Box

Cork : 

Naturally occurring and sourced from the cork oak tree without the need for cutting down the tree or damaging it so it is eco-friendly and known to have antimicrobial properties.

In addition, it has great sound absorption abilities since the cellular structure of cork oak enables it to have a lot of air spaces to dampen sound.

Although its sound blocking capabilities leaves much to be desired.

Acoustic Plywood:

Similar to Cork acoustic plywood is great at sound absorption but even better at controlling sound as it fragments standing sound waves, reflects high frequencies and absorbs less bass.

It also can minimise impact vibrations especially the no sanded plywood kind which in addition resists moisture better than common wood.

Medium Density Fiberboard (MDF):

MDF is a type of engineered wood made by fusing broken-down softwood or hardwood fibres with resin binder and wax under heat and pressure to create panels.

Its specialty is that it shares STC Rating (for more information about STC rating please refer to https://kineticsnoise.com/downloads/analysis/AT001099B.pdf), density and thickness with a drywall. It has excellent acoustical abilities due to its density.

However, it’s not easy to work with as it releases VOCs during cutting, absorbs moisture quickly and is highly flammable.

Oriented Strand Board (OSB):

It is manufactured in a similar way to MDF by pressing various wood strands together and securing the layer or fibres with adhesives.

What makes OSB such a great choice as a boxing material is unlike MDF it does not absorb moisture quickly and it has an impressive STC rating.

Some studies have shown a combination of OSB wood, glass wool and air actually creates more effective sound blocking and sound absorption than some concrete and brick buildings.

Methods to Soundproof a Box

These are the 8 most effective methods to soundproofing a box

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Styrofoam or Acoustic Foam Insulation

Styrofoam or acoustic foam are ideal materials to line the inside of the box whichever material it is made from. They are highly porous and easy to install using adhesive.

This will also increase the density of the box necessary to dampen sound vibrations. Use 3M Styrofoam adhesive to properly affix and line the inside walls of the box.

Egg crates

Using old discarded egg carts line the insides of the box maxing sure to cut out the egg crates as required inside the box. Egg carts are effective in dampening noise since they consist of large air pockets and therefore makes for an effective decoupling material.

Make sure to apply acoustic spray as it absorbs sound energy instead of reflecting it, reducing reverberation times and overall noise within a space.   

It can be applied directly to most substrates including concrete, plasterboard, GRP, steel, glass, expanded polystyrene and more

It can enhance prevention of noise reverberation, provide thermal insulation and provide effective moisture control.

Hardwood Box like OSB, Plywood

It is pertinent to motion in conjunction with the whatever lining you go for, selecting the appropriate material of the box construction to enhance soundproofing should be first on the list.

OSB & Plywood as discussed above provide great sound control, help absorb noise and prevent noise reverberation.

Acoustic Panel Lining:

Composed of compressed mineral wool or foam, sound absorbing acoustic panels absorb sound waves to reduce general noise, clarify speech and limit reverberation in walls within enclosed areas. 

It reduces sound reverberation, echos & volume which make it great material for soundproofing a box. 

Mineral Wool

Mineral wool or Rock wool makes for effective bass traps. All you have to do is build a wood frame, fit the Rockwool boards, and cover it with a nice fabric.

It acts as a high-performance soundproofing insulation material, ideal for soundproofing an enclosed structure such as a box. It’s soft and flexible, making it easy to tightly stuff the batts into standard styrofoam cavities.

Acoustic Putty

Flexible acoustic and intumescent putty are designed to maintain acoustic properties & structural integrity in flexible structural assemblies.

They are suitable for most flexible structural partitions constructed from various materials. They have good acoustic, fire and insulation resistance.

Thermal Conversion

This is a material which works by converting sound energy into trace heat energy.

When sound waves come into contact with the membrane, it vibrates the molecules of the materials which in turn creates friction which is cleverly converted to a trace heat energy.

Thus the material works by converting a more problematic acoustic energy into a less problematic heat energy which is simply transferred through the material sideways to reduce flanking transmissions.

In any serious or advanced strategy to isolate sound, this is an absolute must to work in tandem with the other principles.

At only 3mm thick, the depth of the material is hardly noticeable in the grand scheme of things, but the benefits to uplift acoustic performance are immense.

The material has an optimum balance of mass and flexibility, however it does not rely only on its mass for acoustic performance, making it a unique and standalone sound proofing material.

Constrained Layer Damping 

Constrained layer damping is a principle of using specific materials in particular ratios to reduce the natural resonant frequencies of the structure, thus reducing the resulting flanking transmissions from one side of the structure to the other.

Damping compounds are effective when applied between two rigid panels, such as drywall or plasterboard for example.

As a result, when the sound hits it, shearing forces between the panels creates friction in the damping layer and the sound ceases as it is converted to heat, in essence thermal conversion occurs.

This solution is ideal for low-frequency noises

Conclusion

This blog addresses the ways of making a box soundproof. We dived into what were the key principles of soundproofing so that the audience can make an informed decision for soundproofing a box.

Moreover, when opting for soundproofing one must make sure the size, shape and material of the box conform to the budget in  which it can be made soundproof.

Many of the methods discussed are sensitive to price, size, purpose of the box and not all methods will work as effectively in terms of either sound proofing or costs.

 If you have any questions or comments please let us know.

FAQs about soundproofing a box:

Still, have questions about what to do or use? I get it. Here’s a rundown of substitutions and whatnot to help you complete your soundproofing project.

Can I use Homemade Sound Deadening Materials?

Add anything you want. The idea is to make a thicker barrier between the walls of that box and its exterior.

However, the stuff I’ve listed above is something that has been tested and works exceedingly well.

Can I use Egg Cartons to Soundproof my Cardboard Box?

Look, egg cartons are great for keeping eggs from breaking. But as far as blocking noise, they’re a total dud.

Cardboard boxes already have thin walls, so adding a thin material on there isn’t going to really help.

If you’re walking your kid through trying to do this and egg cartons come up, ask them why they think it might work and then show them why it won’t. It’s a great way to learn a life lesson.

Can I Soundproof a Cardboard Box From the Outside?

Yes, which might be easier if you’re making a smaller soundproof cardboard box. You’ll just add all the materials discussed above to the outside.

It will probably look a bit ugly though, so if you want to pretty it up, by all means, add some decorative paper to give it some style.

Can Bubble Wrap Be Used for Soundproofing a box?

Another smart question that might come is about bubble wrap. While that stuff is fun to pop, it lacks the mass needed to be effective.

The air pockets really won’t lend enough sound reduction to make a difference, plus they will keep popping over time when pressed, and you’d have to keep replacing them.

Should you Build Your Own Box for Better Results?

You can certainly build your own box if you’re going to use it for a long time. There are videos that can teach you how to build your very own wooden box. It will give you better results than the cardboard box simply because wood is thicker.

However, if you’re not up for woodworking or just experimenting, soundproofing a cardboard box will give you some pretty effective results.

References:

Acousti Blok Team. (2020, March 16). 30 TYPES OF SOUNDPROOFING MATERIALS EXPLAINED. Retrieved from Acousti Blok: https://www.acoustiblok.co.uk/soundproofing-materials/

ADAMS, M. (2019, September 19). How to Make a Sound Proof Box. Retrieved from Hunker: https://www.hunker.com/13408105/how-to-make-a-sound-proof-box

AudioMav Team. (2017, June 10). How to Soundproof a Cardboard Box at Home Step-by-Step. Retrieved from AudioMav: https://audiomav.com/how-to-soundproof-a-cardboard-box-at-home-step-by-step/

Dan. (2017, July 5). How To Build A Soundproof Box For A Generator In 9 Steps. Retrieved from Soundproof Panda: https://soundproofpanda.com/build-soundproof-box/

Dominic. (n.d.). How To Soundproof A Cardboard Box At Home In 8 Simple Steps. Retrieved from soundproofcentral: https://soundproofcentral.com/soundproof-cardboard-box/

Luka. (2018, August 29). How to make a soundproof carboard box in 5 easy steps. Retrieved from Sound Proof Advice: https://soundproofadvice.com/how-to-make-a-soundproof-cardboard-box-in-5-easy-steps/

Sound Proof Guide Team. (2017, January 24). How to Soundproof a Cardboard Box – Step by Step DIY. Retrieved from Sound Proof Guide: https://soundproofguide.com/how-to-soundproof-a-cardboard-box/

Walker, J. (2020, April 2). How to Make a Soundproof Box – In 5 Easy Steps. Retrieved from Sound Proof Expert: https://soundproofexpert.com/how-to-make-a-soundproof-box/

Weekend Builds Team. (2019, December 30). 19 Cool Ideas to Build a Soundproof Box for Air Compressor. Retrieved from Weekend Builds: https://weekendbuilds.com/diy-soundproof-box-for-air-compressor/

What Are Good Materials To Build A Soundproof Box? (2020, November 12). Retrieved from Home Studio Expert: https://homestudioexpert.com/what-are-good-materials-to-build-a-soundproof-box/