Acoustic Isolation of Cinemas
For the all-encompassing, big screen cinema, with surround sound, to achieve the ultimate in audience experience, it is crucial that external noise does not interfere with the show. Distracting noise breaks audience concentration and enjoyment, disconnecting them from the storyline and experience.
It is for this reason that cinemas typically require high levels of isolation to prevent noise leaking between screens and from/to public areas. It is very important to ensure the isolation is designed correctly to ensure the film experience is maintained. Cinema isolation is a little different to isolating other rooms or buildings due to the seating and walkways.
Special Acoustic Considerations for Cinemas
Typically, the walkways and seating in a cinema screen are separated acoustically from the rest of the building structure. This requires a complex floating floor design, which needs to interface with the walls and raked seating. Usually this is an isolated steel framework.
Mason U.K. has worked with specialist concrete contractors to design and construct isolated tiered seating, walls and ceilings to meet the acoustic requirements.
The ‘Box in a Box’ Isolation Method
Depending upon the arrangement of the screens and other acoustic influences. It is often necessary to create a ‘Box in a box’ design. A ‘Box in a box’ design is where an internal room is built within the existing structure. This internal box is totally isolated acoustically from the surrounding building. This is achieved via a combination of air-gaps, LDS rubber (previously neoprene) and springs, depending upon loads and natural frequencies. These are built into the floors, walls and ceilings.
Elements involved in ‘Box in a Box’ Construction:
We have broken up the description of ‘Box in a Box’ construction into 3 main areas listed below;
Acoustic Floating Floors
There are several types of floating floors available; wood, concrete, jack up, spring, and rubber, with many variations of these too. To view these in more detail and learn about the different floating floor types please scroll down the page and click the relevant box. Essentially the acoustic concrete floor is held up with rubber or spring, this creates an air gap that isolates noise in the same fashion as double glazing.
Acoustically Isolated Walls
The walls are then built up along the edges of this flooring. They are attached to the existing structure via acoustic wall ties and sway braces (type DNSB-A sway brace for stud walls, and DNSB-BM brace for block work walls). At the head of the wall a resilient angle is often required (we recommend the AB-716 head restraint) to provide an acoustic seal. More information on these can be found at the bottom of this page or on our ‘Isolated Walls’ page (via the products drop down menu).
Suspended Ceilings
The final part is a suspended ceiling. Acoustic ceilings are suspended on drop rods from the concrete soffit or timber joists. Usually we would recommend our HDQF hangers, although Mason UK has a large range of rubber and spring hangers available, the selection of which depends on the ceiling construction and the nature of the vibration.
The HDQF has been designed to easily clip onto the common MF ceiling grid ceiling system. A more detailed description of this product is available at the bottom of the screen. To view the other hanger types available please click the drop down products menu at the top of the screen and select the relevant section.
Conclusion
Mason U.K. has worked on numerous cinema projects, isolating multiple screens. To view a selection of these please click on the past projects in the right hand grey bar. We can provide suitable products and design expertise to help with these aspects, recognising that each job is unique and providing the perfect acoustic isolation solution.
Should you have any questions, require advice or wish to make an order, please contact our friendly engineers.
Typical Products Used
HDQF-A Rubber Ceiling Hangers
HDQF quick fit ceiling hangers use high quality low dynamic stiffness natural rubber. This hanger has been designed to aid the contractor with a quick and easy installation of suspended acoustic ceilings.
Elastomeric Isolation Bearings
Elastomeric bearings can be made from a variety of materials and are very effective against most medium to high frequency vibration sources. The material choice depends on the environment, but natural rubber is the most common choice due to its low dynamic stiffness.
DNSB-A Sway Brace/Wall Tie
DNSB-A is a low frequency wall tie. This sway brace has a bolt end for stud walls or hooked end for masonry walls.
Jack-Up LDS Rubber Floating Floors
The Mason FSN Jack-Up acoustic floor system can be used as the crucial part of achieving box in box construction for studios or rooms requiring a high level of acoustic separation or simply providing acoustic or impact isolation from one area to another.
Concrete Floating Floors
Floating floors systems are used for many purposes, predominantly to prevent noise passing through the floor but also to isolate against vibration and impact.
