Blocking infrasound is extremely difficult because sound waves below 20 Hz have wavelengths so long (17 meters or more) that they pass through most building materials with barely any loss. Conventional soundproofing methods that work well for mid- and high-frequency noise are largely ineffective here. But a combination of approaches, from adding mass to your walls to using tuned resonators and active cancellation systems, can meaningfully reduce infrasound levels in a space.
Why Infrasound Is So Hard to Stop
Sound gets harder to block as its frequency drops. A 10 Hz wave has a wavelength of about 34 meters, which means it bends around obstacles, passes through walls, and penetrates gaps that would stop higher-frequency sounds entirely. Standard acoustic foam, fiberglass panels, and even double-pane windows are designed for frequencies above 100 Hz and do almost nothing against infrasound.
The sources are also widespread. Wind turbines generate infrasound below 20 Hz due to their slow blade rotation (10 to 30 rpm). HVAC systems, compressors, pumping stations, gas motors, and heavy diesel machinery all produce energy concentrated in the low-frequency range at or below 20 Hz. Even acoustic barriers installed along highways can vibrate and produce dominant energy below 20 Hz. If you live near any of these, the infrasound may enter your home through the walls, floor, and ceiling simultaneously.
Adding Mass and Structural Density
The most fundamental principle for blocking any sound is mass. Heavier, denser barriers absorb more sound energy before it passes through. For infrasound, this means you need significantly more mass than typical construction provides. Thick poured concrete, dense masonry block, and layered drywall with viscoelastic damping compounds between sheets all help, but the gains per layer are modest at frequencies below 20 Hz. Where a single layer of drywall might reduce mid-frequency noise by 30 or more decibels, you might see only a few decibels of reduction at 10 Hz.
The practical takeaway: if you’re building or renovating, use the densest wall construction you can. Multiple layers of drywall with damping compound between them, concrete or CMU block walls, and a fully sealed building envelope will collectively chip away at infrasound transmission. Sealing every gap matters because infrasound will exploit any air path, including ventilation ducts, door gaps, and unsealed outlets on exterior walls. A room that leaks air leaks infrasound.
Tuned Helmholtz Resonators
A Helmholtz resonator is essentially a hollow cavity with a narrow neck opening, similar to blowing across a bottle top. When sized correctly, the air in the neck acts as a vibrating mass and the air inside the cavity acts as a spring. At the resonant frequency, the device absorbs sound energy efficiently. The resonant frequency depends on the neck diameter, neck length, and cavity volume. Larger cavities with wider necks resonate at lower frequencies.
For infrasound, the cavities need to be large. Targeting a frequency of, say, 10 Hz requires a resonator with a substantial internal volume. A single resonator also only works at one narrow frequency band, which is a major limitation. Research into arrays of differently sized resonators, arranged using mathematical sequences like the Fibonacci pattern, has shown that combining unequal units in a panel can widen the effective absorption range and increase the overall absorption coefficient without increasing the total volume of the system. This approach creates multiple resonance peaks across a broader frequency band.
These aren’t consumer products you can buy off the shelf. But if you’re dealing with a known, consistent infrasound source at a specific frequency (a particular piece of industrial equipment, for instance), a custom-built resonator or resonator array tuned to that frequency can be effective. Acoustic engineers can design and install these systems.
Active Noise Cancellation
Active noise control (ANC) works by generating a sound wave that’s the mirror image of the unwanted noise, canceling it out. This technology is actually well suited to low frequencies. Traditional ANC systems are most effective at low, steady-state frequencies because the long wavelengths give the system more time to calculate and produce the opposing signal. Higher frequencies, with their shorter wavelengths and faster fluctuations, are harder for ANC to track.
For a room or enclosed space with a consistent infrasound source, an ANC system uses microphones to detect the incoming low-frequency waves and speakers (typically subwoofers) to produce the canceling signal. The challenge is that infrasound requires speakers capable of moving large volumes of air at very low frequencies, which means large drivers or specialized subwoofer enclosures. The system also needs reference microphones placed between the source and the listening area to give the processor enough lead time.
Newer deep-learning-based ANC systems are expanding what’s possible, achieving wideband noise reduction rather than being limited to narrow frequency bands. But for residential use, practical ANC systems for infrasound remain specialized installations rather than consumer devices. If the source is predictable and stationary, like a nearby industrial fan or compressor, ANC is one of the more promising approaches.
Vibration Isolation for Structure-Borne Infrasound
Infrasound doesn’t just travel through the air. It also travels through the ground and building structure as vibration, then re-radiates as airborne sound inside your rooms. This is called structure-borne transmission, and it often accounts for more of the perceived infrasound indoors than what comes through the air.
Vibration isolation pads or springs beneath machinery can reduce infrasound at the source. If you’re the one receiving it rather than producing it, floating your floor on rubber isolators or neoprene pads can help decouple your living space from ground vibrations. A “room within a room” design, where the inner room’s walls, floor, and ceiling are physically separated from the outer structure by resilient mounts, is the gold standard for low-frequency isolation in recording studios and can be adapted for residential use. The air gap between the inner and outer shells, combined with the mass of both layers, provides far better low-frequency isolation than any single wall.
Identifying and Reducing the Source
Before investing in structural modifications, it’s worth identifying exactly where your infrasound is coming from. A sound level meter with a microphone capable of measuring below 20 Hz can help pinpoint whether the dominant path is airborne or structural, and what frequency you’re dealing with. Some smartphone apps claim to measure low frequencies, but dedicated equipment is far more reliable below 20 Hz.
Common indoor sources are easier to address than you might expect. HVAC systems are frequent culprits, particularly large air handlers and duct resonances. Adding duct silencers designed for low frequencies, reducing fan speeds with variable-frequency drives, or modifying ductwork to eliminate standing waves can cut infrasound at the source. If a neighbor’s equipment is the problem, sometimes relocating or mounting the equipment on vibration isolators resolves the issue without any modification to your own space.
What Actually Works in Practice
No single method eliminates infrasound completely. The most effective strategy combines several approaches: maximize the mass and airtightness of your building envelope, isolate the structure from ground vibrations, seal every air leak, and if needed, add a tuned resonator or active cancellation system targeting the dominant frequency. Each layer of defense may only reduce levels by a few decibels, but stacking them can bring the total reduction into a meaningful range.
It’s also worth noting that the perception threshold for infrasound is high. At 10 Hz, the average person doesn’t perceive the sound until it reaches about 96 decibels, and at 2 Hz, the threshold rises to roughly 124 decibels. About 90 to 95 percent of people can perceive infrasound at levels corresponding to 86 dB on the G-weighted scale used for infrasound measurement. So even modest reductions in level can push exposure below the point where most people would notice it. A controlled study exposing noise-sensitive adults to simulated wind turbine infrasound for 72 hours found that high-level but inaudible infrasound did not produce measurable physiological or psychological effects, and none of the 36 participants developed symptoms. This suggests that once levels drop below the perception threshold, the health concerns largely disappear, making “good enough” reduction a realistic and worthwhile goal.