Acoustical Ceiling Tiles
Airborne vs. Impact Noise: How to Block Each Type Effectively
Noise problems in buildings almost always fall into two main categories: airborne noise and impact noise. Understanding airborne vs impact noise is essential if you’re trying to solve complaints about loud footsteps, audible voices through walls, or the constant rhythmic thump of a neighbor’s subwoofer. The trick is that these two forms of sound behave differently, so the methods used to block them must also be different. If you treat one without the other, you’ll likely be disappointed with the results.
This article breaks down the differences between airborne and impact noise, explains how sound travels through buildings, and outlines the most effective noise reduction techniques. We’ll also cover how STC and IIC ratings are used to measure performance, and which soundproofing materials work best for walls, floors, ceilings, and windows.
Understanding the Basics of Sound Transmission
Sound moves through buildings in two main ways: as pressure waves of energy traveling through the air or by vibrating structures. In acoustics, we call these two paths airborne noise and impact noise. To complicate matters further, both can spread through indirect paths–this is known as flanking transmission–and generally includes airborne sounds that travel around sound barriers – through ductwork, pipes, and gaps in wall and ceiling assemblies.
Airborne sound flows through the air, finding every opening, whereas impact noise travels through solid structures, moving along rigid connections from one surface to the next.
What is Airborne Noise?
Airborne noise is what most people think of when they say something is “loud.” It is sound energy that travels through the air and then leaks through gaps, windows, doors, ducts or thin walls. Examples include:
- Voices and conversations
- TV or music
- Kitchen noise in restaurants
- Barking dogs or office chatter
Airborne noise sneaks in wherever air can move. As a general rule of thumb, anywhere air (or water if you prefer something you can see/visualize) can pass through, noise can easily pass through those locations as well. That’s why sealing cracks and adding barriers with good acoustical sealant–sometimes backed with acoustic insulation–is so effective. Airborne noise, like water, travels via the path of least resistance, whether that’s a small gap under a door, through an HVAC duct, or if the room is air tight, it would then travel through a thin partition wall.
What is Impact Noise?
Impact noise comes from physical contact with a surface. The most common example is footsteps–also called footfall noise. Understanding the differences between airborne and footfall noise helps clarify why these sounds travel differently and require distinct soundproofing strategies. Other examples include chairs scraping across a floor, dropped objects, or even mechanical vibrations from HVAC units and noisy plumbing in adjacent spaces.
Impact noise creates structure-borne sound, which is mechanical energy traveling through joists, studs, and concrete. For example, if someone drops something upstairs, the ceiling vibrates, which in turn shakes the connected walls. Those walls then radiate sound into the room below, like a giant speaker.
You can think of impact energy like electricity: as long as there’s a continuous rigid connection, it will transfer from surface to surface. That’s why floor soundproofing and ceiling isolation strategies are so important.
Key Differences Between Airborne and Impact Noise
Although both cause frustration, airborne and impact noise differ in their sources, transmission paths, and how performance is measured.
Source
- Airborne noise starts in the air–voices, TVs, music–when vibrating objects (like the cone of a speaker) push sound waves into space.
- Impact noise comes from direct contact, like footsteps or moving furniture, that send vibrations into the structure.
Path of Travel
- Airborne sound travels through the air away from the noise source and often slips through cracks, ducts, and lightweight barriers.
- Impact sound becomes structure-borne sound, moving through joists, studs, and slabs before radiating back out as audible noise.
Measurement
- Airborne noise is rated using STC (Sound Transmission Class).
- Impact noise is rated with IIC (Impact Insulation Class).
Knowing the difference between STC vs IIC ratings is key: a wall with high STC won’t stop a footfall noise problem, just as an isolated floor won’t fix voices traveling through a wall.
Real-World Examples
- Offices – overhearing conversations through partitions (airborne).
- Condos – footsteps or dropped objects from above (impact).
- Hotels – voices through walls and carts rolling down hallways (both airborne and impact).
This table shows how each type of sound is created, how it travels, the key acoustic ratings used to measure it, and the recommended solutions for each type of noise, for easy reference:
| Airborne Noise | Impact Noise | |
| Source | Sound waves in air (voices, TV, music) | Vibrations from impacts (footsteps, furniture moving) |
| Path | Travels through air leaks and lightweight walls | Transfers as structure-borne sound through rigid materials |
| Measurement | STC rating | IIC rating |
| Solutions | Seal gaps and cracks, add mass, utilize decoupled wall assemblies or constrained layer dampeners, upgrade to soundproof windows and doors | Use underlayment for soundproofing, decoupled wall assemblies, floating floors, resilient ceilings |
The takeaway: airborne and impact noise need different treatments. Implementing the wrong solutions is one of the most common mistakes. Only by targeting both can you achieve reliable sound isolation.
Soundproofing Solutions for Airborne Noise
To control airborne noise, the strategy is simple: block air leaks, add mass, or create decoupled or dampened wall assemblies. The most effective approaches include:
- Sealing gaps and cracks – Even small holes around outlets, ducts, and door frames can allow sound to leak through.
- Upgrading windows and doors – Installing soundproof windows and doors with proper seals makes a significant difference.
- Adding mass and density – Extra layers of drywall with damping compounds like Green Glue help absorb and block sound.
- Decoupled or dampened wall assemblies– Using RSIC-1 clips to decouple the drywall from the stud, or adding Green Glue (a very effective vibration dampener) between two layers of drywall make it much harder for sound to be transmitted through a wall.
- Acoustical Panels – While not designed to block sound, panels can reduce reverberation in the room and improve sound clarity, which makes airborne noise less intrusive.
Where Airborne Noise Shows Up Most
Airborne noise is a frequent issue in:
- Shared walls between offices or meeting rooms
- Schools needing classroom privacy
- Hospitals where patient confidentiality is essential
- Hotels and condos with thin walls
In all these cases, airborne noise control comes down to airtight construction and high-mass barriers.
How to Reduce Impact Noise Through Floors and Ceilings
Impact noise is trickier because it’s not just “air leakage.” It’s physical vibrations moving through the structure. Stopping it requires sound isolation and vibration control techniques that break the direct path of transmission.
Common solutions include:
- Underlayment for soundproofing – A dense rubber or composite layer installed beneath flooring helps absorb footfall energy before it reaches the structure.
- Floating floors – Building a decoupled floor system creates a buffer that prevents impact vibration from traveling into the joists.
- Resilient channels – Installing channels that greatly reduce the amount of contact that the drywall has with the joists and allows the ceiling to “float,” reducing vibration transfer.
- Acoustic insulation – While insulation alone doesn’t block impact noise, adding it between joists helps improve the overall performance of the floor/ceiling system by reducing the amount of reverberation in the overall assembly.
Best Practices for Reducing Ceiling Impact Noise
When dealing with ceiling impact noise, layering solutions works best. A high-performing assembly often includes:
- Floating floor system above to reduce vibrations at the source.
- Resilient ceiling system below using clips and hat channels.
- Acoustic insulation in the cavity to absorb airborne sound bouncing around in the floor/ceiling assembly.
- Additional layers of drywall with damping material like Green Glue for vibration control and reduction.
This combination addresses both structure-borne sound and airborne leakage.
How to Combine Solutions for Maximum Effect
Most real-world noise problems involve both airborne and impact sound. That’s why combining treatments is the most reliable way to achieve comfort and privacy.
For example:
- Use RSIC-1 clips and resilient channels to decouple drywall.
- Add Green Glue between multiple drywall layers for damping where a lot of noise reduction is needed.
- Install acoustical panels in noisy rooms to tame reverb and reduce ambient noise levels.
- Pair soundproof windows and solid core doors with floor underlayment for complete assemblies.
The key is layering–no single product solves every problem. Effective assemblies combine decoupling, damping, absorption, and sealing.
Choosing the Right Materials for Your Space
Selecting the right soundproofing materials depends on the type of noise problem and the construction of the space.
- For homeowners – Focus on practical upgrades like door seals, acoustical panels, and window replacements or inserts. These are cost-effective and non-invasive.
- For contractors or facility managers – Pay attention to STC vs IIC ratings when choosing assemblies. Products like resilient channels, underlayments, and clip systems offer higher performance but require professional installation.
Remember that every project is unique. While most general noise reduction techniques are useful, dialing in the right mix of products requires looking at the details of your construction. That’s why it’s best to consult with the experts at Acoustical Surfaces. We can recommend custom solutions that address both airborne and impact noise effectively.
Final Thoughts
The bottom line: solving noise problems means understanding the source, and an understanding of airborne vs impact noise is the first step. Airborne sound leaks through gaps and thin barriers, while impact sound travels as vibration through rigid structures. Each requires a different strategy, but both must be considered for true peace and quiet.
Whether you’re dealing with noise through a wall, ceiling impact noise, or footstep vibrations, the right mix of soundproofing materials, acoustic insulation, and floor soundproofing methods can dramatically improve comfort.
When you’re ready to solve your noise challenges, contact our experts for help choosing the right soundproofing materials and an acoustical design plan tailored to your space.
