An acoustic enclosure – sometimes called sound or noise enclosures, or soundproof enclosures – are soundproof chambers designed to keep noise in or out. They can be small and portable or building-sized. Acoustic enclosures are often made out of heavy-duty materials like sheet metal, timber, loaded vinyl, plasterboard or glass.
The use of these materials to encompass the noise source helps to stop noise from radiating out. Acoustic enclosures can be used to isolate and block noise from leaving the area and reaching outside the enclosure, or they can be used to stop outside noise from getting into interior spaces.
Acoustic enclosures may also be used to block or reduce the force of noise that lies at frequencies that could interfere with precise manufacturing processes or measurements, or certain noise frequencies that hit the most sensitive part of human hearing.
How do acoustic enclosures work?
In order to understand how acoustic enclosures work, it’s necessary to first understand soundproofing. It sounds simple, but it can get complex quickly. The process of soundproofing is simply to block noise from either entering or leaving a room, and it works by using materials that either block the sound or absorb it. Often very substantial noise can’t be blocked or absorbed completely, but noise reduction is possible.
Sound is energy produced by vibration. For instance, when you hit a drum, the skin of the drum vibrates quickly enough that it forces the air to vibrate. The air then moves and carries the energy everywhere around the drum. The physical process of sound is what produces and sends it through the air. The psychological process is what happens in our brain and ears. It converts the energy into what we then call noise, music, speech, etc.
Every physical object causes vibrations when it moves in the air. This leads to the creation of waves in the air that then continue to travel as a form of sound. The sound, much like light, comes from its source. The difference is that sound can’t travel through a vacuum. It has to move through something like glass, air, water, metal, etc. In order to effectively soundproof, you have to block the sound on its way from the source, and stop its movement through the air.
To block this sound, a number of materials can be used, but not every material is soundproof. Soundproof materials must be able to isolate and absorb sound and vibration in order to properly block or reduce the sound escaping/entering the soundproof enclosure. Acoustic enclosures prevent this radiation of noise outwards from a source or protect against exterior noises from getting in. Generally, any enclosure classified as an acoustic enclosure is designed specifically to minimise, eliminate or at least reduce sound.
In order to do this, generally, the exterior is made of a material that is solid and dense, like galvanised steel. The interior then will be covered with absorbent materials like acoustic wool. Sound absorbing materials usually have a protective face and are made of perforated sheet metal, perforated foil, or perforated vinyl. Advanced or specialized acoustic enclosures often incorporate vibration attenuation technology. Vibration isolation requires components such as springs, rubber mounts, air cushions, pads or mats, and cork or fiberglass inserts.
Any entrances, windows and ventilation openings are kept to a minimum, but air inlets and outlets will be fitted with silencers. When optimum performance is required, doors are usually enclosed by an acoustic tunnel too.
Applications for acoustic enclosures
Acoustic enclosures can be used in many different ways. Here are some important applications:
- Blocking sound to protect workers. An acoustic enclosure may be used for an in-factory office
- Blocking sound to protect sensitive equipment, like metrology tools or semiconductor equipment
- Noise reduction for compressors/fans
- Dampening the sound of manufacturing equipment, air conditioning and refrigeration systems & power generators
Some acoustic enclosures are designed less to block all sound and more to block specific frequencies. Sound waves above 85 decibels can be harmful to individuals constantly subjected to them and can lead to headaches, insomnia, increased allergy symptoms and other health issues, so blocking the frequencies within the range of human hearing can help alleviate noise pollution.
Similarly, some frequencies are specifically harmful to certain kinds of machinery or equipment, so blocking these frequencies from entering/escaping is necessary. Acoustic enclosures reduce these problems and help local governments adhere to strict noise ordinances.
Some acoustic enclosures are portable and lightweight, but many are designed to be fixed in place. Some examples of this would be personnel shelters, cooling towers, control rooms or observation rooms. These fixed structures typically contain acoustic ceiling and wall tile and acoustic foam.
If you are interested in seeing what an acoustic enclosure can do for you, whether it’s for commercial or domestic purposes, contact us at Environ Technologies today. We can design and build bespoke enclosure systems to meet your specific project requirements.