How sound attenuation works at different frequencies – a practical guide to a better sound environment

Sound insulation and sound absorption are rarely a "one size fits all" solution.
This is because different sounds occur at different frequencies – and what works perfectly against a sharp treble sound can be almost ineffective against deep bass or thumping structure noise. Therefore, it is important to understand how the frequency of sound affects both how we perceive it and which materials can actually stop or dampen it.
Once you match the right insulation to the right frequency range, you can achieve a dramatic improvement in the sound environment, often with less effort than you might think.

In practice, this means distinguishing between, for example, airborne sound such as voices, music, and TV sound, and low-frequency vibrations from machines, subwoofers, or footsteps.
Low frequencies often require heavy sound barriers and effective vibration damping, while mid- and high-frequency sounds are best dampened with porous absorbers and smart placement. For many projects, the best solution is a combination of several layers that together break the sound's path
– rather than trying to solve everything with a single material.

In this guide, we go through how to choose the right sound insulation depending on frequency and sound type. You will get a clear explanation of what characterizes low, mid-high, and high frequencies, which materials work best in each area, and how to build an effective whole. The goal is for you to be able to make the right choice right away
– whether you want to stop bass leakage, reduce machine vibrations, or eliminate echoes and sharp sounds in a particular environment.

Here are some advantages of choosing the right sound insulation for different frequencies

Maximum effect where the problem actually exists
When you adapt the sound insulation to the frequency, you get a solution that hits the mark right away.
Low-frequency vibrations require heavy barriers and vibration damping, while speech and sharp sounds are better dampened with absorbent materials.
The result is that you don't "overdampen" the wrong things, but get the most sound reduction per investment.

Less risk of costly mispurchases
A common pitfall is buying a material that looks right but doesn't work for the type of sound you want to stop.
By understanding frequencies, you avoid costly rework and can choose the right product from the start – saving both time and money.

Better overall acoustics and greater comfort
When the right frequency range is attenuated, the experience in the entire room is improved. Bass is controlled, dialogue becomes clearer, and the room feels calmer without becoming "dead."
This creates a more balanced sound environment that is comfortable to be in for longer periods of time.

More effective solutions with less material
The right material in the right place often means you need to use less insulation to achieve the same result.
Instead of covering large areas with the wrong product, you can work smart and target the areas where the sound energy actually is.

Provides control of both airborne sound and structure-borne sound
Frequency-based planning allows you to handle multiple types of sound simultaneously.
For example, you can stop bass and vibrations in the structure while removing echoes and reflections in the air.
This is the key to professional results in everything from home theaters to machine rooms.

Sustainable and future-proof investment
When you build a solution based on frequency, you create an acoustic whole that continues to function even if the use of the room changes.
Whether you replace equipment, rearrange furniture, or add new sound sources, you already have the right foundation for effective sound absorption.

Easier to achieve clear goals, such as RT60 or dB requirements
In projects where you need to meet specific acoustic goals (e.g., reverberation time, sound level, or standard requirements), frequency adaptation is crucial.
This makes measurable goals easier to achieve and provides security in both private and professional environments.

More professional results that you can feel right away
The biggest benefit is noticeable in everyday life: you get a room where the sound behaves "right." Nothing rumbles unnecessarily, nothing sounds sharp and disturbing, and you don't get the feeling that the sound has a life of its own. You notice the difference right away—and it lasts over time.

Step-by-step: How to dampen different frequencies – from bass and vibrations to sharp sounds

To achieve successful sound attenuation, you need to match the right material with the right frequency range, as different sounds require different solutions.
Low frequencies (bass and structure-borne noise) require different solutions than speech and sharp sounds.

Also, keep in mind that sound can be either airborne (spread through the air) or structure-borne/vibrations (spread through the structure).
Follow the steps below to build a correct and effective solution, whether you want to dampen bass, speech, or sharp sound peaks—without unnecessary mispurchases.

Step 1: Identify the frequency range that is causing the disturbance

Listen to the sound and determine what type of frequency you are having problems with:

• Low frequencies (approx. 20–200 Hz): rumbling bass, thumping, engine noise, vibrations, structure-borne noise.
• Midrange (approx. 200–2000 Hz): voices, TV sound, music, everyday sounds.
• High frequencies (approx. 2000–20,000 Hz): rattling, clinking, sharp sounds, echoes, "s" sounds, and "t" sounds.

A simple rule of thumb: the more you feel the sound in your body or the floor, the lower the frequency (and usually structure-borne sound). If you hear it clearly in the air, it is airborne sound, and if the sound is sharp, it is high frequencies.

Step 2: Determine whether the sound is airborne or vibration-borne

• Airborne sound spreads through the air and bounces between surfaces (speech, TV, music).
• Structure-borne sound/vibrations spread through the building (machines, bass, footsteps, blows).

If the sound is clearly audible in other rooms despite the door being closed, it is often structure-borne sound or low-frequency bass.

Step 3: Dampen low frequencies and vibrations (bass & structure-borne sound)

Low frequencies are best stopped by vibration damping as the first layer, preferably supplemented with absorption.

• Start with Polaric as the first layer against the surface: Polaric "kills" vibrations in the structure when it is closest to the floor/wall/mounting. This is the right choice when the problem is structure-borne sound, thumping, or bass that shakes the house.
• Supplement with Egg where you want both absorption and vibration damping: Egg is a high-density absorbent that not only absorbs airborne sound but also dampens vibrations. Perfect around noisy sources or behind barriers.
• Spot dampen as needed with Dampio: Dampio is used under machine feet or at contact points to remove local vibrations and rattling.

Placement tip: low frequencies collect in corners and at floor contact points – start there.

Step 4: Dampen mid-range frequencies (speech, everyday sounds, music)

The midrange is what we hear most in everyday life. Soft, porous absorbers work best here.

• Use PES for midrange: PES is soft and very effective at absorbing sound, especially speech, dialogue, and music.
  It removes reverberation and makes the sound image clearer and calmer.
• Place PES on primary reflection surfaces: side walls at ear level, behind the listening position, and preferably on the ceiling if the room is "bouncy."
  
  We recommend placing sound-absorbing material on approximately 20-30% of the total reflective surface area in the room.
  So if your room is 50 square meters, cover 10-15 square meters with absorbers to achieve a noticeable difference.
  
  

Step 5: Dampen high frequencies (echo, clang, sharp sounds)

High frequencies are most easily dampened by removing hard reflections.

• Absorbers on hard surfaces: PES also works here, but the focus is on removing the largest reflective surfaces.
• Textiles as a complement: curtains, carpets, and furniture help to soften the soundscape.

Placement tips: high frequencies bounce like light in a mirror – dampen large, smooth surfaces first (our recommendation is: sound absorbers on the ceiling).

Step 6: Block airborne sound with a barrier layer

When sound needs to be stopped between rooms, through cabinets or structures, a heavy sound barrier is needed.

• MLV is your barrier for airborne sound: it is used in walls, ceilings, cabinet sides, or around noisy spaces to block sound leakage.
• Absorb behind the barrier: place Egg behind MLV to capture the sound that the barrier stops, with the pattern shape directed towards the sound source.
  For easier installation, it can be mounted in front of MLV.
  
  If Egg does not fit, use Neo as a smooth, space-saving alternative (available in 4-7 mm sizes).
  
  

Step 7: Build a comprehensive solution with multiple layers

Effective soundproofing almost always requires a combination:

• Polaric (first layer) to stop vibrations/low frequencies in the structure.
• MLV (barrier) to block airborne sound.
• Egg or Neo behind the barrier to absorb the blocked sound and reduce resonance.
• PES in the room to control midrange/high frequencies and reduce reverberation.

It is the combination that provides professional results, not a single material.

Step 8: Test and fine-tune

Once the measures are in place, listen again:

• Have the bass and vibrations become calmer?
• Are voices and dialogue clearer?
• Have echoes and sharp peaks disappeared?

If any areas are still bothering you, make additional adjustments locally where the sound is loudest. Small adjustments can have a big impact.

Products that are good for soundproofing and sound absorption at different frequencies

When choosing sound insulation, it is crucial to match the right product to the right frequency range. Some materials are designed to block airborne sound, others to stop vibrations and low frequencies, and some absorb best in the mid-range. Here is a clear product list to help you build the right overall solution.

SilentDirect MLV – Sound barrier for airborne sound

SilentDirect MLV (Mass Loaded Vinyl) is a heavy, flexible sound barrier. It is mainly used when you want to block airborne sound such as voices, TV sound, music, and general noise propagation between rooms or through thin structures. MLV is installed in walls, ceilings, floors, or cabinet sides and acts as a "stop disc" that prevents sound from passing through.

SilentDirect Polaric – First layer against vibrations and low frequencies

SilentDirect Polaric is a heavy butyl-based damping mat that should be placed as the first layer against the surface when the problem is structure-borne noise, vibrations, or low-frequency bass. Polaric "kills" the vibrations in the structure before they have time to spread further. It is ideal under machines, subwoofers, exercise equipment, or in structures where thumping and resonance are the main problems.

SilentDirect Egg – High-density absorber that also dampens vibrations

SilentDirect Egg is a high-quality absorber with a patterned structure and high density. It is unique in that it both absorbs airborne sound and dampens vibrations. Egg is therefore perfect for use behind an MLV barrier to take care of the sound that is blocked, or around noisy sources where you need double the effect (absorption + vibration control). The product's pattern also acts as a diffuser, breaking down sound waves into smaller waves that are easier for the material to absorb. This is why you see absorbers with this pattern in music studios and podcast studios, for example.

SilentDirect Neo – Smooth vibration and sound absorber

SilentDirect Neo is a smooth NBR mat that is mainly used for vibration damping and stability, often together with Polaric under machines, equipment, or under floors. Neo can also be installed behind MLV as an absorbent layer when there is no room for Egg – Neo has a smooth surface and low profile.

SilentDirect PES – First choice for midrange and reverberation

SilentDirect PES is soft, thick, and porous, making it very effective in the midrange (speech, dialogue, music, everyday sounds). PES is used on walls and ceilings to absorb reflections and reduce reverberation. It makes the sound clearer and the room more comfortable without you having to over-insulate the structure. The absorber works best in the room where it is installed and "eats up" the noise you experience, giving you a more relaxed everyday life and a safer working environment.

SilentDirect Dampio – Point damping for local vibrations

SilentDirect Dampio are vibration-damping plates for point loading. They are used where vibrations occur at contact points, such as under machine feet, stands, mountings, or hard joints. Dampio is an effective addition when you want to eliminate local rattling and structure-borne noise problems.

Recommended combination (frequency-based total solution)

• Structure-borne noise/low frequency: Polaric as the first layer + Neo or Dampio for extra stability/point damping.
• Airborne sound to be blocked: MLV as a barrier + Egg behind (or Neo 4-7 mm if space is limited).
• Midrange/reverberation in the room: PES on walls and ceilings to absorb reflections.
  
  Summary
  To effectively dampen different frequencies, you need to match the material to the character of the sound. Polaric is used first against vibrations and low frequencies, MLV blocks airborne sound, Egg absorbs and dampens vibrations behind barriers or around sources, Neo is a smooth alternative when space is tight, such as under floors, and PES is the first choice for midrange and reverberation in the room. With the right order and placement, you will get immediate results – quieter, clearer, and more controlled.

With this product division, you get the right material for the right frequency – which gives maximum sound reduction, better acoustics, and a solution that works in practice.

Did you know that...

...two sounds that are equally loud in decibels can be perceived as completely different in terms of annoyance – simply because they are at different frequencies? A low, muffled bass at 50 Hz can feel like a "rumbling in the body" even when the meter shows the same level as a sharp sound at 2,000 Hz. That is why some sounds are impossible to ignore, even though they do not seem particularly loud.

Few people also know that low frequencies do not behave like “normal sound” – they behave more like pressure waves. That is why a subwoofer can be heard more clearly in the next room than where it is located. Bass tends to take the hardest route: through floors, walls, and frames, as if the house were one big speaker.

And here's a real surprise: the same acoustic panel can be brilliant for voices and completely useless for bass. This is because soft, porous absorbers (such as PES) "eat" midrange and treble, but low frequencies are so energy-rich that they just pass right through unless you stop them with mass or vibration damping first.

The most unexpected thing? A heavy sound barrier like MLV can stop airborne sound effectively—but if you don't have an absorbent layer behind it (like Egg), the blocked sound can remain and build resonance in the structure, much like when you shout into a box with a lid. That's why professional solutions are almost always based on multiple layers working together.

So next time you think, "I just need to soundproof the room," remember that sound is not a single thing. It's a whole spectrum. And it's only when you dampen the right frequency with the right material that you get that magical feeling of the room suddenly becoming really quiet.