Is Carpet Padding Good for Soundproofing?

Part of setting up a home studio is acoustic and soundproofing treatment to get the best sound. Luckily, there is a wide variety of soundproofing materials, from acoustic foam panels to acoustic membrane, and these materials have different best use scenarios. But is carpet padding good for soundproofing, too?

Carpet padding is a good enough material for soundproofing as it helps dampen sound. The denser the carpet pad is, the more it can resist the force of sound and keep it from totally penetrating through the floor. But when it comes to treating your studio, there are better materials available.

In this article, I will discuss what makes carpet padding or underlay a good soundproofing material, the different types of carpet underlays, and the pros and cons of using one to soundproof a room. I will also talk about soundproofing principles to help you understand why carpet padding may or may not give you the results you need and expect.

Why People Use Carpet Padding as a Soundproofing Material

Carpet padding not only protects your carpeting but also does a pretty good job of dampening sound to a certain degree. 

And while soundproofing isn’t really its main function, people use it in lieu of special acoustic isolation treatments because it is cheaper.

Benefits of Using Carpet Pads for Soundproofing

Soft carpet underlays can help reduce impact noise, which is the noise that comes from footsteps or anything that has direct contact with the floor. 

Carpet paddings effectively lessen the force of the impact and therefore dampen this noise. As such, this kind of material is more important for an upstairs room so people in the room directly below it wouldn’t find footsteps too noisy.

Downsides of Using Carpet Pads for Soundproofing

The only problem is that while carpet padding can reduce impact noise, it can’t do the same with air or ambient noise going through the floor, including people’s voices and music. 

So, even if you have carpet underlay on your floor and people in the room below won’t hear your footsteps or your thumping, they will still be able to hear it when you play music loudly or when you shout.

When to Use Carpet Pads for Soundproofing

When it comes to using carpet paddings as an acoustic treatment for your home studio, results would depend on where you install them.

It is not recommended that you cover your studio floor with carpet padding if you already treated your walls and ceiling. 

Sound experts advise leaving your floor as a reflective surface to keep the balance. Otherwise, the sound could end up becoming too muffled.

Meanwhile, using carpet padding on your studio walls and ceiling would generally help reduce echoes and keep sound from bouncing off. But the results may not be as great as you’d want. 

Carpet underlays are still considered relatively thin and can therefore only absorb high frequencies. 

Check out my ultimate guide to the home studios floor type for recording.

Choosing Carpet Padding for Soundproofing 

There are a few different types of carpet underlays for you to choose from, and they have different properties, so they affect the behavior of sound in different ways. 

However, these differences in their soundproofing capabilities are not that significant.

The three basic types of carpet padding in terms of materials are:

• Foam underlays are a firmer version of the same type of foam used in mattresses, car seats, and upholstered furniture, which may be made of:
  • Prime polyurethane foam is made of non-recycled materials.
  • Bonded polyurethane foam is made of recycled foam pressed together.
  • Froth polyurethane foam is made of viscoelastic foam like Memory Foam.

• Rubber underlays may either be:
  • Waffle rubber is made by molding synthetic or natural rubber.
  • Flat sponge rubber, a firm and dense padding material.

• Fiber underlays are made of existing natural or synthetic fibers that are interlocked into a felt sheet.

These carpet pads also come in varying densities and thicknesses.

If you want to reduce impact noise, foam carpet pads are the best option. However, when it comes to ambient noise, the best way to know exactly how effective each product would be is to inquire about its Noise Reduction Coefficient (NRC). 

NRC is the rating used to determine how well a material absorbs sound and reduces ambient noise, and the higher the NRC, the better it is at noise reduction.

You can learn more about NRC and measuring absorption from this page.

For more information, check out if carpeted walls help with soundproofing.

Understanding Soundproofing

To decide if you should use carpet padding for soundproofing, it’s crucial to first understand the basics of soundproofing as a whole.

Different rooms have different acoustic properties, and these properties will determine their soundproofing requirements. 

Let’s go over the five basic principles of soundproofing below.

Absorption

Acoustic absorption is when sound waves hit a material, object, or structure, and it takes in their energy instead of reflecting it. A part of this absorbed energy is converted into heat and is considered lost. 

Another part is transmitted through the absorbing material. 

Materials that absorb and soak up sound energy include open-cell woven types. These materials are available in various thicknesses and densities with increasing effect. 

They are typically installed to fill open cavities to prevent additional resonance, amplification, or reverberation of sound waves.

Carpet padding will help to absorb sound, especially if the underlay is thick, too. However, for soundproofing a room, you would be better off with acoustic panels on the walls.

Deflection

You can achieve deflection of sound by adding density and mass to your wall, ceiling, or floor. Solid materials that are dense or heavy and have a thick consistency can help block sound. 

You add such materials between the sound source and the receiving point so that the sound wave will need to pass through an additional bulk, thus reducing its energy.

As sound waves hit the dense materials, they will produce vibration. The sound waves will pass the energy from one end to the other through the material with vibration. 

Deflection using dense and heavy materials, such as ply, plasterboard, drywall, or thick concrete, is more effective with ambient sounds than with impact noise.

As carpet padding is not overly dense, it will not work well in sound deflection.

Decoupling

Decoupling is mechanically separating a wall’s two sides so that they vibrate separately and independently. 

It is an effective way of isolating sound on one side of the wall and keeping sound waves from getting through to the other side of the wall.  

Decoupling reduces the strength of the acoustic vibrations and therefore slows their potential passage through the wall. Because it involves the wall structure, decoupling is best done while the building is still under construction.

Constrained Layer Damping

Constrained layer damping involves using specific materials in certain ratios to reduce a structure’s – like a wall’s – natural resonant frequencies, therefore reducing the flanking transmissions from one side to the other.

The principle of damping compounds is effective when you apply it between drywalls, plasterboards, or any two rigid panels. 

As such, when sound waves hit the panels, the shearing forces between them generate friction in the damping layer. When this happens, the sound is converted to heat and ceases.

This soundproofing solution is great for low-frequency sounds.

Thermal Conversion

When sound waves encounter or contact an isolation membrane, they vibrate the membrane’s molecules, which, in turn, creates friction that is converted to trace heat energy. 

Simply put, this material converts problematic sound energy into less problematic heat energy, which is then transferred sideways through the material to lessen flanking transmissions.

The material’s depth is hardly noticeable, but it has great benefits when it comes to uplifting acoustic performance. The material also boasts an optimum balance of flexibility and mass, although it does not rely only on mass for acoustic performance.

Conclusion

A carpet padding is good for soundproofing as it can reduce echoes and absorb sound, especially high-frequency ones. 

How efficient a carpet underlay gives you the acoustics you want in your room or studio will depend on certain factors. These factors include where you install the padding, what material the padding is made of, the treatments you’ve already done, and the general acoustic properties of the room.

Moreover, while carpet padding can be used for soundproofing, there are much better and more effective acoustic treatment materials available.

Sources

• Avalon Flooring: The Importance of Carpet Padding
• Find Any Answer: Is Carpet Padding Good for Soundproofing
• Home Recording: Carpet Padding?
• Real Traps: Measuring Absorption And The Numbers Game
• Buy Insulation Product Store: What is Decoupling
• Wikipedia: Memory Foam