Acoustics_Vocabulary


 * Acoustics **The study of sound. In everyday language also refers to how sound is perceived in particular premises.


 * Articulation Class (AC) **A classification of suspended ceilings according to their ability to contribute to the acoustic privacy between work stations. AC is calculated from the Interzone Attenuation according to ASTM E-1110.


 * Articulation Loss of CONSonants (%-Alcons) **One method of objectively measuring speech intelligibility is Articulation Loss of CONSonants (%-Alcons), showing the number of consonants being missed as a percentage. Consonants play a much more significant role in speech intelligibility than vowels. If the consonants are heard clearly, the speech can be understood more easily.
 * Sound absorbers **Materials and structures with the ability to take up sound energy and convert it into other forms of energy. They improve room acoustics by removing sound reflections, thus reducing the noise and the reverberation time.


 * Sound Absorption Average (SAA) **Single value for the sound absorption according to ASTM C 423, including the third octaves in the frequency range 200-2500 Hz.


 * Sound Absorption Class **Classification of sound absorbers into Sound Absorption Classes A-E, according to EN ISO 11654, including frequencies 200-5000 Hz.


 * Sound insulation **The ability of a building element or building structure to reduce the sound transmission through it.


 * Sound pressure level (dB) **<span style="background-color: #ffffff; font-family: Arial,Helvetica,sans-serif;">The pressure variations caused by sound waves in air are called sound pressure. The lowest sound pressure level which can be heard is 0 dB, known as the hearing threshold. The highest level which can be tolerated is called the pain threshold and is around 120 dB.


 * <span style="font-family: Arial,Helvetica,sans-serif;">Speech intelligibility **<span style="background-color: #ffffff; font-family: Arial,Helvetica,sans-serif;">Speech intelligibility is directly dependent on the level of background noise, reverberation time and the shape of the room. Different methods are used to evaluate speech intelligibility, the most common ones are RASTI, STI and %-Alcons.