Guide to choosing the right soundproofing for different frequencies
Why frequencies matter in soundproofing
All sounds consist of vibrations that travel through air and materials – but different frequencies behave in different ways. This means that no single solution works for all types of noise problems. To create effective soundproofing, it is important to understand which frequencies dominate and how they interact with walls, floors, ceilings, or technical equipment. Whether it's a home, office, studio, or industrial hall, selecting the right material is crucial for the result.
Low-frequency sound – requires construction and mass
Low-frequency sounds, such as deep bass tones, vibrations from machines, traffic noise, or washing machines, have long wavelengths that easily pass through even solid walls and floors. These sounds travel through the structure and create structure-borne noise that is difficult to reduce unless built correctly from the ground up.
To effectively reduce low-frequency noise, a combination of several techniques is required:
Air gap
An air pocket between the walls is necessary – at least 100–300 mm depending on how deep the frequency is. The deeper the bass, the larger the air gap needed.
Decoupled wall or double construction
A freestanding wall, built with at least 200mm deep wooden or steel studs, is best insulated with SilentDirect Egg or SilentDirect Neo in the air gap. The structure should not be mechanically connected to the original wall.
Massive boards
Use multiple layers of drywall or a combination of OSB and drywall. Three to four boards on the front of the frame are ideal – each board adds about 3 dB of reduction.
SilentDirect MLV
Applied directly to the studs before the boards are mounted, preferably in multiple layers. MLV is particularly effective at blocking airborne low-frequency sound.
SilentDirect Polaric or Neo
Mounted between the structure and the floor or wall contact points to reduce structure-borne noise and vibrations.
SilentDirect Seal
Seals gaps and transitions. Important to prevent sound from leaking through even the smallest air gaps.
When low-frequency noise is properly insulated, mass, distance, and acoustic separation are required – simply “covering” the wall is not enough. A poorly built structure without an air gap or with too few layers provides almost no effect.
Mid-frequency sound – effective insulation with the right material
Mid-frequency sound consists mainly of speech, TV audio, kitchen appliances, and similar sources. Here, SilentDirect MLV works very well thanks to its high density and flexibility. For wall insulation, MLV is mounted behind drywall or on the front of studs. Sealing with SilentDirect Seal around connections further improves the result. In combination with this, sound-absorbing panels are used in the room, such as SilentDirect PES Wall or Ceiling, to reduce reflections and prevent sound from bouncing further.
High-frequency sound – short wavelength, easy to dampen
Treble sounds, such as bird chirps, doorbells, or keyboard clicks, have short wavelengths that reflect easily but are also effectively absorbed. Here, sound-absorbing materials in the room are often sufficient. SilentDirect PES Wall, PES Ceiling, or fabric-covered absorbers are ideal choices and are mounted directly on walls or ceilings. In technical spaces where appearance is not important, SilentDirect Egg provides very high absorption for both high and mid frequencies.
Combine the right products for the full frequency spectrum
Most noise issues span multiple frequency ranges, meaning that several products need to work together. SilentDirect MLV effectively blocks airborne noise. SilentDirect Neo, Polaric, and Egg reduce vibrations and absorb sound energy. SilentDirect Seal ensures the construction is airtight – essential for all materials to perform at their best.
Create the right solution for the right sound
Choosing the right soundproofing is not just about buying thick materials – it’s about understanding how sound is generated, how it travels, and how it is best stopped. With the right air gap, proper sealing, the correct number of layers, and the right product selection, you get a solution that truly works – whether you're building a quiet bedroom, a professional studio, or a technical space in an industrial environment. SilentDirect’s range is designed to meet these exact needs – from deep bass tones to sharp treble sounds.