Does Carpet Absorb Sound and Reduce Noise in Rooms

Carpet is commonly cited as a simple way to reduce noise, but questions remain about how much sound carpet actually absorbs and which types work best. This article explains the acoustic properties of carpet, how it interacts with airborne and impact noise, measurement standards used by acousticians, and practical guidance for choosing and maintaining carpet to improve room sound.

Question	Short Answer
Does carpet absorb sound?	Yes—primarily airborne sound and mid-to-high frequencies
Does carpet stop footsteps?	Reduces impact noise but often needs underlay or additional treatments
Best carpet for acoustics	Dense fibers, thick pile, and quality underlay

How Sound Travels In Rooms

Sound Travels As Waves Through Air And Through Building Structures, Creating Two Main Types Of Noise: airborne noise (voices, music) and impact noise (footsteps, furniture thumps). Airborne noise Interacts With Surfaces Causing Reflections, Absorption, And Transmission.

Hard, reflective surfaces such as tile, glass, and hardwood cause strong reflections and reverberation, while Soft, porous materials absorb sound energy by converting it into heat. Understanding these mechanisms clarifies why carpet is effective for some sound problems but not all.

How Carpet Absorbs Sound

Carpet Absorbs Sound By Providing A Porous Surface Where Airborne Sound Waves Lose Energy As They Move Through Fibers And Backing. This Is Most Effective At Mid-To-High Frequencies, Which Are Common In Speech And Domestic Noises.

When sound waves strike carpet fibers, friction and viscous losses occur inside the pile and backing layers, reducing reflected energy. Thicker pile and more porous backing increase the path length for sound and improve absorption.

Carpet Pile And Density

Pile Height And Density Influence Absorption: Longer And Denser Pile Typically Absorbs More Mid-To-High Frequency Sound, While Low-Pile Commercial Carpets Absorb Less. However, overly dense or tightly woven carpets may reflect some frequencies if they lack porosity.

Backing And Underlay

The Carpet Backing And Underlay (Padding) Play A Critical Role In Acoustic Performance. Soft, Thick Underlay Adds Mass And Decoupling, Reducing Impact Noise Transmission To Floors Below.

Measuring Sound Absorption: NRC And STC

Two Standard Metrics Help Compare Materials: NRC (Noise Reduction Coefficient) Describes How Much Sound A Material Absorbs On Average Across Frequencies, While STC (Sound Transmission Class) Measures How Well A Barrier Blocks Airborne Sound Between Spaces.

Carpet Speeds Up Reverberation Reduction (Higher NRC) But Has Limited Impact On Transmission Loss (STC) Unless Combined With Other Mass And Insulation Strategies.

Frequencies Carpet Works Best For

Carpet Excels At Absorbing High-Frequency Energy—Voices, TV Dialog, And High-Pitched Noise. It Is Less Effective For Low-Frequency Bass And Deep Rumbles, Which Require Bulkier, heavier absorbers or bass traps.

For Example, Carpet Will Make A Living Room Sound Less “Bright” By Reducing Early Reflections, But It Won’t Eliminate Low-Frequency Boom From Powerful Subwoofers.

Carpet Vs Other Flooring For Acoustic Performance

Compared To Hard Floors, Carpet Provides Substantially Lower Reverberation Times And Less Audible Reflection. Hard Surfaces Produce Clearer Echoes And Longer Decay Times.

Flooring Type	Typical Acoustic Effect
Carpet With Underlay	Reduces Reverberation, Dampens Footsteps
Hardwood Or Tile	Increases Reflections, Higher Reverberation
Area Rugs	Local Reduction Of Reflections, Helpful In Open Rooms

Impact Noise: Footsteps And Structure-Borne Sound

Carpet Can Reduce Perceived Footstep Noise By Absorbing The Initial Impact Energy On The Surface, But Significant Reduction Of Structure-Borne Noise Often Requires Quality Underlay Or Structural Decoupling (e.g., floating floors or resilient channels).

In Multi-Unit Buildings, Building Codes And Rating Systems May Require Specific Underlay Thickness Or Assemblies To Meet Impact Insulation Class (IIC) Values.

Practical Tips To Improve Room Acoustics With Carpet

Choose Carpet With A Higher Pile And Dense, Porous Fibers For Better Absorption. Pairing Carpet With A High-Quality Underlay Provides The Best Impact And Airborne Noise Reduction.

• Use Area Rugs On Hard Floors To Cut Reflections In Target Zones Like Under Coffee Tables Or Near Speakers.
• Install Thick Underpad When Replacing Flooring To Improve IIC And Walking Comfort.
• Cover Large Bare Surfaces (Walls/Ceilings) With Soft Furnishings, Curtains, Or Acoustic Panels To Address Remaining Reflections.

When Carpet Alone Isn’t Enough

If The Issue Is Low-Frequency Noise, Structural Vibration, Or Sound Transmission Between Units, Carpet May Only Provide Partial Relief. In Those Cases, Combine Carpet With Mass, Damping, Or Decoupling Strategies.

Examples Include Adding Mass-Loaded Vinyl, Improving Wall Or Ceiling Assemblies, Or Installing Floating Subfloors Designed For Impact Isolation.

Choosing Carpet For Different Rooms And Needs

For Living Rooms And Bedrooms Where Comfort And Speech Intelligibility Matter, Medium-To-High Pile Carpet With Soft Padding Is A Strong Choice To Make Spaces Less Reverberant and more comfortable.

For Apartments And Multi-Unit Buildings, Consider Specified IIC/RW Ratings And Thicker Underlay To Reduce Complaints About Footstep Transmission.

Durability, Maintenance And Acoustic Performance Over Time

Carpet Acoustic Properties Can Change As Fibers Flatten And Dirt Accumulates. Regular Vacuuming And Professional Cleaning Help Maintain Absorption Performance And Extend Life.

Choose Durable Fibers And Proper Installation To Avoid Compaction Of Pile, Which Reduces Airflow Through The Carpet And Lowers Absorption Over Its Lifetime.

Cost-Benefit And Environmental Considerations

Acoustic Carpet And Underlay Can Be Cost-Effective Compared To Major Structural Soundproofing, Especially For Improving Room Acoustics. However, For Sound Transmission Problems, Investments In Assemblies Or Structural Solutions May Offer Better Long-Term Value.

Consumers May Also Evaluate Sustainable Materials: recycled fibers, low-VOC adhesives, and CRI Green Label certified products help balance acoustic goals with indoor air quality and environmental impact.

Installation Best Practices For Acoustic Performance

Proper Installation Is Critical: Tightly Stretched Carpet With Consistent Seams And Correct Underlay Placement Ensures Optimal Acoustic Behavior And Avoids Gaps That Can Reduce performance.

Edge Treatments, Transitions, And Underlay Thickness Should Follow Manufacturer Guidelines and Local Codes to meet expected sound ratings and durability.

Testing And Verification

To Validate Acoustic Improvements, Professionals Use Measurements Like Reverberation Time (RT60), NRC Tests, And Field STC/IIC Tests. Objective Testing Helps Compare Before-And-After Performance And Guides Further Interventions.

Homeowners Can Perform Simple Listening Tests: clap, play recorded speech, or compare footstep loudness in adjacent rooms before and after carpet installation.

Summary Of Key Points

Carpet Reduces Mid-To-High Frequency Airborne Sound And Damps Footsteps, Especially When Combined With Quality Underlay. It Is Less Effective For Low-Frequency Noise And Structural Transmission Without Additional Measures.

For Best Results, Select Appropriate Pile, Use Thick Underpad, Follow Proper Installation, And Combine Carpet With Other Acoustic Treatments When Needed.

Further Resources

For Detailed Specifications, Consult ASTM Standards For Acoustic Testing, Building Code Requirements For Multi-Family Impact Ratings, And Carpet Manufacturer Data Sheets. Professional Acoustic Consultants Can Provide Targeted Solutions For Complex Sound Problems.

Relevant Sources Include Industry Bodies Like The Acoustical Society, ASTM, And Flooring Industry Technical Guides For NRC, STC, And IIC Ratings.