Isolation Demo FAQ

1What is the difference between STC (Sound Transmission Class) and TL (Transmission Loss) Ratings?
Transmission Loss is simply defined as the loss of sound as it passes through the wall. It represents a loss of decibels through the wall and is also frequency dependent. The higher a TL rating is for a certain frequency, the more isolation will be accomplished at that frequency. As a rule of thumb, TL ratings will increase with frequency. However, this is theoretical, and actual TL ratings do not increase exactly as theory would predict. The STC, meanwhile, is a single number used to assess the quality of sound isolation done by a wall. It is calculated by using a best fit of standardized STC results to TL measurements. Because it is not frequency dependent, one shouldn’t only look at STC to judge the isolation quality of a wall.
2How do these simulations compare to real life?
We have based these simulations off real-life measurements to create as accurate of simulations as possible. However, room aspects other than wall type will affect sound isolation. Floor/ceiling description, quality of construction, faulty material, doors or windows in the wall, and countless other factors will affect the sound isolation of a room. Our simulation does a good job of showing a rough idea of the isolation one can expect from a certain wall, as well as showing the differences between different walls and their effectiveness.
3How were these audio simulations made?
The simulations were made using WaveLab software by Steinberg. We manipulated the file to reflect the TL data. All wall TL values used in this simulation came from testing done at NRCC Laboratories. For more walls tested by NRCC, visit
4What song is used as the audio example?
The music used in this simulation is the song, “Swagger & Sway,” provided by our friends Henry French & The Shameless. Check them out!
5What is the best way to listen to this simulator?
We recommend using decent quality speakers or headphones (preferably not simply your laptop/phone speakers) as low frequencies will not be replicated well in low-quality sound systems, and low frequencies are the most difficult to isolate.
6How should I set my volume for this simulator?
Set the volume based on the, “No Partition” file. Turn volume up until it is loud enough that it is slightly uncomfortable, and do not adjust the volume as you compare to the other walls.
7I see Type X gypsum board. What does that mean? Is it different from regular drywall?
Type X Drywall is drywall that has a fire rating, while regular drywall is not fire-rated.
8How common are these wall types?
The standard studded wall with half-inch drywall and 2x4 wood studs is very common. As the walls become more complex, however, they become less and less common. Our experience has shown that each project comes with its own unique needs, and our design for isolation specifications vary accordingly.
9What are the ways that sound can go between airborne noise and structure-borne noise?
Airborne noises are transmitted through the air and through barriers, while structure-borne noises come from impacts on the structure itself. An airborne noise can manifest itself in ways such as shouting from adjacent rooms, dogs barking, or music playing loudly. Structure-borne noises come from vibrations transmitted through walls or even footsteps on the floor above.
10Is it possible to fix isolation problems in a room that already exists?
Particularly for sound isolation, planning is key to maximize results. Many problems can be fixed before construction even begins, and many problems can be avoided by planning room layouts well. However, if a room has already been constructed and is found to have sound isolation problems, it is still possible to attenuate the problem! This will typically require construction work, which is unfortunate, but can be done. Be sure to work with a consultant to ensure best results!
11How was the cost per square foot determined?
The cost/ft2 amounts are estimates, and should not be taken as exact values. Many of these materials can be found at common “big box” hardware supply chains. As material costs often vary by location, we recommend that you develop your own materials estimates based on costs, including shipping, from your own preferred vendors.