A Sound Transmission Class or STC rating provides a rough estimate of the reduction in sound level across a wall from one space into another. All else being equal, a wall with a rating of STC 60 will result in sound levels that are on the order of 10 dB lower than a wall with a rating of STC 50. This relationship is only approximate because the improvement will not be the same at every frequency and depends on the source of the sound.
The sound files associated with each wall are simple tones with the same relative level as the STC ratings, so that the tone for the STC 60 wall is 10 dB lower than the tone for the STC 50 wall, and so forth. This is intended to help users experience the changes interactively. This is not intended to be a simulation of any particular wall or source; subjective reaction to noise is dependent on many factors (such as background noise level, time of day, frequency of occurrence, spectral characteristics) that cannot be adequately simulated in an on-line demonstration.
Simulated tones developed by Veneklasen Associates