When buying a new sound system, a good start is with a stc ratings chart. This chart ranks systems based on the sound levels they produce, from 125 Hz to four thousand Hz. Sounds that fall below or above this range can be problematic, but many common noise problems can be attributed to sounds above this range, such as a deep male voice, trucks, and the shrill ringing of a cell phone.
Sound transmission class
Sound transmission class is a standard for comparing the sound quality of a building to its surrounding environment. It describes how sound can be transmitted from an outdoor source into a building. It is based on the ASTM E-1332 Standard Classification for Rating Outdoor-Indoor Sound Attenuation and considers source noise with frequencies as low as 80 Hz. Low frequencies are given a higher weight than higher frequencies. Typically, this value is used to assess exterior glazing assemblies.
STC ratings measure the amount of sound that passes through a building and are commonly used in architectural acoustics. The sound transmission class is buildings’ most commonly used sound reduction measurement. It is an industry standard when calculating the amount of noise reduced by a building barrier.
Sound transmission index
The STC, or sound transmission class, is a metric used to compare the noise reduction capabilities of different building elements and materials. The TL value at 16 standard frequencies is plotted on a graph and compared to the standard STC reference curves. Walls closest to the 35 STC curve are said to have an STC rating of 35. Sound transmission is a key issue in construction because most complaints about sound isolation are related to noise sources below this frequency range.
Despite its importance in open-plan offices, babble-like noises often disrupt conversations. The STC rating is a useful tool for assessing the quality of open-plan offices. Using the STC rating chart, office spaces can be rated for sound transmission. The listed STI values are higher than those in standard noise insulation tests. Sound transmission index ratings are not a substitute for sound-dampening materials.
Sound transmission class rating
STC ratings are a basic measure of sound reduction and are commonly used in the design of acoustic spaces. Originally developed to protect speech privacy, STC ratings are today’s most common sound reduction measurement. They represent the difference between sound levels on one side of a wall and on the other. While the number of STC ratings is staggering, it is relatively easy to understand how they work. To start, consider what exactly an STC rating means.
The STC rating charts compare building materials based on their ability to reduce noise in a given frequency range. The range of sounds tested by the STC is from 125 Hz to 4000 Hz. Noises that fall into this range include bass drums, deep male voices, truck horns, and the shrill ringing of a telephone. Soundproofing products in this range should have an STC rating of 40 or higher.
How to calculate STC rating?
To get an idea of how much sound can be transmitted over a given distance, consider the volume difference on either side. Then divide this number by the total frequencies, such as 16 Hz. The STC rating should fall between 20 and 65; the higher the number, the better. This is useful information because many sources of noise complaints are below 125 Hz, so a higher STC rating means less noise.
Final Words
The STC ratings chart is one of the most common benchmarks used for soundproofing products. This measurement considers the impact of noise on human health, the environment, and more. The range of STC ratings ranges from 125 to 4000 Hz. Many common noises begin below or above this range, such as bass drums, trucks, deep male voices, and the shrill ring of a telephone.
