Sound Isolation
Sound Isolation or as some might call it sound - proofing, is often the most underestimated aspect of acoustic treatment for a home theater. Many believe that by adding acoustic panels to the walls and or ceiling, all sound can be stopped from entering or exiting the theater space. This is untrue. Acoustic Panels only provide noise control, which refers to treating noise from within a space. More information on this is available in the Acoustic Treatments section of this site.
Sound Isolation refers to limiting how much noise reaches the room from the outside and how much of the sound in the room leaks to the outside. A well isolated space must address both sound transmission factors and impact resonances. Acoustic Innovations offers five different solutions to meet these goals all of which can be classified into two categories of functionality:
Sound Transmission
Sounds that leave the theater are generally low frequency waves coming from the subwoofer or any speaker with a low cross-over. Since the shapes of these waves are wide with a broad dispersion pattern, they are able to travel well beyond a 2x4 wall structure covered with drywall. The act of sound traveling through a substrate is called sound transmission and the strength in which the sound passes through a material is measured by a rating called STC (Sound Transmission Class). Soundcor Green, Iso-Floor, and Iso-Pads fall under this category.
Impact Resonance
The most conflicting sound that enters the space is foot fall. When someone is walking on a floor above the home theater room, the energy from their steps is transferred to the floor and from the floor into the sound sensitive area if the home theater structure is not decoupled properly from the rest of the home. Foot Fall can also include other vibrations from the home. These sounds can be very distracting to those watching a movie as not only can it be heard but felt in some cases. Foot Falls are measured by a rating called IIC (Impact Isolation Class) and products such as our Iso-Clips and Iso-Blocs are in this category.
Sound Isolation products are measured for performance, differently then Acoustic Panels. Learn more here.
Sound Isolation Products
Sound - Proofing products are measured by an STC rating (Sound Transmission Class) which is a way of quantifying how well a wall can isolate sound. The STC measures the decibel reduction that a partition can provide. The human ear perceives a reduction of 10 dB as a volume reduction of 50%. If a 90 dB sound is reduced to a 30dB sound on the other side of a wall, floor or ceiling, then the partition has a STC of 40. A typical stud wall has a STC Rating of 33 so a person standing outside the theater will hear 33 db less then whatever sound level is being played in the theater. Most theaters built on THX standards must play as high as 105 DB, however most dialog is held at 65- 80 dB. To experience different dB levels visit your home stereo receiver or processor and toggle the volume. The onscreen display should show the decibel level as a number and dB after it.
Acoustic Treatments in theaters are classified by an NRC rating (Noise Reduction Coefficient) which is a measure of the amount of sound energy that a surface absorbs when struck by that sound energy. An NRC of 0 indicates perfect reflection while an NRC of 1 indicates perfect absorption. The room size and amount of reflective surfaces effect a room's reverberation time, and the longer the time the more echo and acoustical nuances exist. Placing acoustic treatment's that have a high NRC rating reduce reverberation time, by absorbing impulse sound. Our 1" depth panel offers a .65 NRC while a 2" depth panel allows for a perfect 1.0 NRC. To learn more about acoustic panels click here.