Soundproofing Vs Sound Absorbing (Key Differences)

Have you ever wondered what the difference is between soundproofing and sound absorption? With both used to treat acoustics, it can be confusing to know which method is right for your needs. So here is the answer.

Soundproofing blocks sound from entering or leaving a room and uses in places where noise needs to be completely blocked. While sound absorption reduces the echo and reverberation of sound within a room and used in places where echo and reverberation need to be reduced, such as music studios or auditoriums.

This article will answer common questions about soundproofing vs sound absorption, so you can strategically choose the right noise control solution for your space. Learning the key differences between these terms will allow you to block unwanted sounds and create your ideal acoustic environment.

Let’s explore what sets these noise reduction methods apart.

How Does Soundproofing Work?

Soundproofing, also called sound blocking, involves using dense materials to prevent noise from transferring between rooms. The goal is to contain sound in one area so it cannot be heard elsewhere.

Sound waves are unable to penetrate through soundproofing materials due to their heavyweight construction. Common soundproofing products include:

  • Mass loaded vinyl
  • Acoustic insulation
  • Concrete and brick walls
  • Double stud walls with insulation
  • Acoustic caulk and sealants

Soundproofing materials are rated by their Sound Transmission Class (STC). This measures how well a material can block airborne noise. The higher the STC rating, the better the soundproofing capability.

Soundproofing is ideal when you want to eliminate external noise like traffic, loud neighbors, machinery etc. It creates a sound barrier so these distracting sounds won’t bother you.

If you are wondering whether soundproofing actually works, I have an article investigating real-world testing data.

How Does Sound Absorption Work?

Sound absorption, also known as acoustic treatment, takes a different approach to noise control. Instead of blocking sound, it absorbs echo, reverberation and excess noise within a room.

Sound absorbing materials have an open, porous structure that allows sound waves to pass through. The fibrous or cellular core then dissipates the acoustic energy so it cannot bounce back into the room. This prevents problems like echo and amplifies sound within the space.

According to a NIH article, there are usually six frequencies used to determine whether a material is sound absorbing: 125 Hz, 250 Hz, 500 Hz, 1000 Hz, 2000 Hz, and 4000 Hz. The absorption coefficients at each frequency are used to calculate the material’s NRC rating.

Acoustic foam panels and ceiling tiles are common sound absorption products. They are rated by the Noise Reduction Coefficient (NRC), with a higher NRC indicating better absorption capability.

Sound absorption is great for improving speech clarity and overall sound quality. It helps control noise that originates within a room, rather than external sounds.

Key Differences Between Soundproofing and Sound Absorption

Now that you understand the basics of how each method works, let’s recap the main differences:

  • Purpose: Soundproofing prevents noise transfer between rooms, absorption controls noise within a room
  • Noise Source: Soundproofing blocks external noise, absorption treats internal noise
  • Materials: Soundproofing uses dense, heavyweight materials while absorption uses lightweight, porous materials
  • Effectiveness: Soundproofing completely blocks noise from transmitting whereas absorption only reduces reverberation

Here is a comparison table summarizing the key differences between soundproofing and sound absorption:

FeatureSoundproofingSound Absorption
PurposeBlocks exterior noise from entering a spaceAbsorbs interior noise and reverberation
MaterialsDense and heavy – mass loaded vinyl, concrete, insulationPorous and lightweight – acoustic foam, fabric, tiles
Noise SourceExternal noises – traffic, machinery, neighborsInternal noises – echoes, amplification, reverb
Rating SystemSTC (Sound Transmission Class) – higher = better blockingNRC (Noise Reduction Coeff.) – higher = better absorption
How It WorksPhysically obstructs sound waves from passing throughAllows sound waves to enter then traps them to prevent bouncing back
Ideal ApplicationsRecording studios, theaters, bedroomsOffices, restaurants, classrooms
Used WithSound absorption materials to treat interior acousticsSoundproofing materials to block exterior noise
Soundproofing Vs Sound Absorbing

So in summary:

  • Use soundproofing when you want to eliminate external noise
  • Use sound absorption when you want to improve clarity and echo issues
  • Soundproofing blocks noise, absorption soaks it up

For a comparison of soundproofing vs acoustic treatment, I suggest reading my guide outlining the differences.

When Should I Choose Soundproofing or Sound Absorption?

Now that you know what sets them apart, how do you decide which method to use? Here are some common scenarios:

Blocking Noise From Neighbors or Outside

If distraction comes from next door, above you, or outside (e.g. traffic, construction etc.) then soundproofing is the way to go. Sound absorption cannot block external noise – it only treats sound within the room. Soundproofing creates a barrier to stop noise transferring through walls and windows.

Creating a Home Theater

A home theater needs sound containment to deliver an immersive watching experience. Soundproofing ensures others don’t hear the booming sound system and that external noise doesn’t ruin the ambiance. Acoustic treatment can complement this by absorbing any internal echoes.

Reducing Echo and Reverb in a Room

Do you hear a lot of echo when talking in a room? Or does sound seem to amplify and resonate? This points to issues with excess reverberation. Sound absorption is the solution. Strategically placed acoustic panels will help absorb, diffuse and deaden the sound.

Enhancing Speech Clarity in Offices and Restaurants

In workplaces and eateries, poor acoustics can make it hard to communicate. Treating these open plan spaces with sound absorbing materials will improve speech intelligibility without blocking noise completely. Employees and guests will be able to converse with less distraction.

Controlling Sound in a Recording Studio

Recording studios need both isolation and tuned room acoustics. A room-within-a-room using soundproofing eliminates all external noise. Monitor speakers and acoustic treatment then allow engineers to mix with precision in the quiet, calibrated space.

As you can see, the ideal solution depends on the noise problem you want to solve. Use soundproofing to block exterior noise and absorption to treat interior acoustics.

Sound Blocking vs Sound Absorbing Materials

Sound blocking and absorbing products differ quite significantly in their construction and composition:

Sound Blocking Materials

Sound blocking materials prevent noise transmission using one or more of these strategies:

  • Mass Loaded Vinyl (MLV) – A heavy limp mass layer that stops noise by its sheer density
  • Insulation – Friction within soundproofing insulation absorbs acoustic energy
  • Decoupled Walls – Separate studs prevent vibration transfer between walls
  • Double Drywall – Layering drywall dampens vibration and adds mass

Typical sound blocking materials include:

  • Concrete and masonry
  • Drywall
  • Insulation like rockwool
  • Loaded vinyl
  • Acoustic sealants

These work by physically obstructing sound waves from passing through using dense mass and staggered studs.

To understand which natural materials work best for absorbing sound, I recommend reading my detailed guide on natural sound absorbing materials.

Sound Absorbing Materials

Sound absorbers have an open cell structure that helps to dissipate acoustic energy. This prevents excessive reverberation within a room. Common traits include:

  • Porous Surfaces – Small holes allow sound to enter and get trapped
  • Fibrous Material – Sound gets absorbed as it passes through fluffy fiber
  • Textured Shapes – Angled surfaces diffuse and scatter sound

Typical sound absorbing products include:

  • Acoustic foam panels
  • Fabric wrapped panels
  • Acoustic ceiling tiles
  • Heavy curtains

These lightweight materials won’t block noise but help clean up echoed sounds using their sound diffusing properties.

To understand the science behind how sound absorbing materials work, read my article explaining the physics of noise reduction.

What Should I Look Out for When Comparing Products?

As per a GMinsights report published in 2020, the acoustic insulation market is projected to grow at a CAGR of around 3.77% to 4.5% through 2025. Rising demand from building and construction along with the automotive industry is driving this steady growth.

To choose effective soundproofing and absorbing products, watch out for:

  • STC and NRC ratings – Higher = better blocking and absorption
  • Entire frequency range – Should cover bass, mid and high frequencies
  • Installation method – Rooms within rooms are most effective
  • Flammability rating – Look for fire-resistant soundproofing
  • Coverage area – Calculate how much you need for your space

Also consider your budget, aesthetics, and room use. Striking the right balance between function and form creates an optimally performing noise-free space.

Professional acousticians can help design a customized solution for your needs.

What are some common soundproofing materials?

Popular soundproofing materials include Mass Loaded Vinyl (MLV), acoustic insulation, Green glue, acoustic caulk, and double drywall. MLV is a dense vinyl sheet that reflects noise.

Insulation made of rockwool or fiberglass absorbs vibrations. Green glue is a viscoelastic compound installed between drywall to dampen vibration. Acoustic caulk seals gaps where noise leaks through. Double drywall adds mass and damping using two layers.

How do you know if a material is a good sound absorber?

Check the Noise Reduction Coefficient (NRC) rating, with higher values indicating better absorption. See if it absorbs a wide frequency range from 125 Hz to 4000 Hz. Look for a porous, open-cell structure that enables sound waves to enter. See if it has an uneven or angular surface that scatters sound. Assess the before and after noise levels at various points after installing it.

Does soundproofing work for blocking outside noise?

Yes, soundproofing effectively blocks exterior noise from disturbing you. It adds mass, isolates vibration, and seals gaps to prevent outside noise like traffic or construction from transmitting indoors. Install acoustical windows with laminated glass.

Add a second interior wall to decouple the exterior wall. Use soundproof curtains to increase the air gap at windows. Apply acoustic sealant to seal gaps where sound enters. Upgrade to solid core exterior doors with thresholds.

If you want to know how effective soundproof curtains are, check out my helpful article by clicking on the link.

What’s the difference between sound damping and sound absorption?

Sound damping converts acoustic energy into imperceptible heat and vibration using materials like Green Glue. Sound absorption allows acoustic energy to pass into a porous sound-trapping material rather than reflect back into a room, using materials like acoustic foam. Damping turns sound waves into heat and vibration. Absorption traps sound waves to prevent reverberation.

Should I use soundproofing or sound absorption in my media room?

Use both soundproofing and absorption in a home media room. Soundproof to contain noise and prevent disturbing others via insulation and double drywall. Add absorption like acoustic panels to reduce echo and improve sound quality by strategic placement to prevent a boomy reverberant sound. Layering internal absorption and external blocking creates an ideal quiet media room.

I have written an in-depth guide on soundproofing doors if you want to learn techniques to isolate and secure room entrances.

Conclusion

Soundproofing aims to block or reduce sound transmission between spaces and typically involves adding mass or constructing barriers. Sound absorbing, on the other hand, involves materials that dampen and absorb sound within a room, reducing echo and reverberation.

Key Takeaways

  • Soundproofing blocks exterior noise using dense materials with high STC ratings, while sound absorption improves interior acoustics using porous materials with high NRC ratings.
  • Choose soundproofing when you want to eliminate noise transfer between rooms or block outside noises. Use sound absorption when you want to reduce echo and excessive reverberation inside a room.
  • Common soundproofing materials include mass loaded vinyl, acoustic insulation, double drywall, and acoustic caulk. Sound absorbing materials include acoustic foam panels, fabric wraps, and acoustic ceiling tiles.
  • Soundproofing contains noise by obstructing sound waves. Sound absorption allows noise to pass through then traps it to prevent bouncing back into the room.
  • For home theaters and recording studios, use both – soundproofing to isolate the room and absorption inside to tune the acoustics.
  • Check product ratings like STC and NRC to compare effectiveness. Also look for coverage of the full frequency range.
  • Hire an acoustic specialist if needed to design a customized noise control solution that balances performance and aesthetics.
  • Now that you understand the differences between these noise control methods, you can confidently treat any sound issue by selecting the right sound blocking or absorbing products.

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