Sound Barriers vs. Sound Absorbers:
What’s the Difference Inside the Aircraft?
A lot of noise emanates from an aircraft’s cabin, but even more noise comes from the outside of a plane. In fact, noise levels can get so high in some aircraft that it can damage one’s hearing over time. Because of this, two types of revolutionary soundproofing materials were created to drastically reduce this damaging noise: sound absorbers and sound barriers.
While both types of noise reduction material reduce unwanted sound, they do so through vastly different means. Keep in mind that proper soundproofing often involves both types of material.
Sound barriers keep unwanted noise from entering or leaving a room. So, in terms of an aircraft, sound barriers keep any sound made within a cabin contained, while outside noise is drastically reduced for those inside the cabin. Sound barriers are typically made from dense, heavy materials and are always found within the walls of a plane.
Sound blocking works by reflecting sound made within the cabin back into the room, virtually blocking any noise from leaving. In order to achieve true sound blocking, consider these three methods.
- Installing dampening compounds between two panels
- Creating mass to block sound using heavy, thick materials
- Decoupling or creating gaps in parts of a structure’s sound to interrupt vibrations
Keep in mind that for stronger aircraft soundproofing, all three methods may be required.
Sound absorbers reduce the echoing and/or reverberation of sound within the cabin from the engine, the vibration of the airframe and the airflow over the airframe. This type of material is typically made of soft, fluffy and porous materials. This helps the product to absorb a portion of the sonic energy of the sound waves.
This process works through specially made sound absorbers that soak up sound and release it through the other side of the wall. While echoes of the sounds are absorbed, the sound itself can be heard from one room to the next.
The following are the three most common types of sound absorbers on the market.
- Panel Absorbers. Also known as membrane or single absorbers, panel absorbers are everyday objects made of non-porous and non-rigid materials.
- Porous Absorbers. The primary function of porous absorbers is to convert sound energy into heat energy.
- Resonance Absorbers. This type of absorber is made up of a mechanical or acoustical oscillation system with plates made of perforated material — perfect for trapping sound and locking it inside.
When installing aircraft soundproofing material, you should understand that every aircraft has its own hot spots in terms of noise. Concentrate your soundproofing efforts toward these spots. But in general, the noisiest areas of a plane are the windows, the firewall, the kick panels, the cowl forward of the windshield and instrument panel, the cabin’s sidewalls, the roof and the wing-roots.
Heavier layers should always be placed where sound is the loudest. In addition to this, the entire cabin should have soundproofing throughout.
Note: You should always consult your airplane’s manufacturer for guidance on proper soundproofing procedures and insulation, as well as soundproofing installation requirements.
Reduce The Noise In Your Aircraft With Duracote
Duracote’s Durasonic line offers the ultimate in noise reduction with flame retardant options. The noise reduction material can be designed to function as a barrier curtain, partition, composite barrier/absorber or even a vibration damping material. And when coupled with a sound absorber, such as a foam, nonwoven material or fiberglass, it helps to create enhanced aircraft soundproofing. Have a question or need more information? Contact us today — we’re here to help!