Acoustics+Vocabulary

    Classification of sound absorbers into Sound Absorption Classes A-E, according to EN ISO 11654, including frequencies 200-5000 Hz.  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.  Means that sound energy is converted into mechanical vibration energy and/or heat energy. Sound absorption is expressed as the sound absorption coefficient //α // or the sound absorption class (A-E) according to EN ISO 11654 or NRC/SAA according to ASTM C 423. 
 * Privacy ** 
 * Acoustic privacy between working places in open plan offices is expressed with the Articulation Class (AC). **
 * Frequency (f) **
 * Stated in Hz (hertz). The higher the value, the lighter the tone (bass - treble). The frequency of speech lies primarily between 125 and 8000 Hz, while audible sound lies between 20 and 20 000 Hz. **<span style="font-family: "Arial","sans-serif";">
 * <span style="color: black; font-family: "Arial","sans-serif"; font-size: 12.0pt; line-height: 115%; mso-ansi-language: EN-US; mso-bidi-font-style: italic;">Sound Absorption Class ** <span style="color: black; font-family: "Arial","sans-serif"; font-size: 12.0pt; line-height: 115%; mso-ansi-language: EN-US; mso-bidi-font-style: italic; mso-bidi-font-weight: bold;">
 * <span style="font-family: "Arial","sans-serif";">Sound Absorbers **
 * <span style="font-family: "Arial","sans-serif";">Sound Absorption **

<span style="font-family: "Arial","sans-serif";"> <span style="color: black; font-family: "Arial","sans-serif"; font-size: 12.0pt; line-height: 115%; mso-ansi-language: EN-US; mso-bidi-font-style: italic; mso-bidi-font-weight: bold;">Single value for the sound absorption according to ASTM C 423, including the third octaves in the frequency range 200-2500 Hz. <span style="color: black; font-family: "Arial","sans-serif"; font-size: 12.0pt; line-height: 115%; mso-ansi-language: EN-US; mso-bidi-font-style: italic; mso-bidi-font-weight: bold;">
 * <span style="color: black; font-family: "Arial","sans-serif"; font-size: 12.0pt; line-height: 115%; mso-ansi-language: EN-US; mso-bidi-font-style: italic;">Sound Absorption Average (SAA) ** <span style="color: black; font-family: "Arial","sans-serif"; font-size: 12.0pt; line-height: 115%; mso-ansi-language: EN-US; mso-bidi-font-style: italic; mso-bidi-font-weight: bold;">

<span style="font-family: "Arial","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.
 * <span style="color: black; font-family: "Arial","sans-serif"; font-size: 12.0pt; line-height: 115%; mso-ansi-language: EN-US; mso-bidi-font-style: italic;">Speech intelligibility ** <span style="color: black; font-family: "Arial","sans-serif"; font-size: 12.0pt; line-height: 115%; mso-ansi-language: EN-US; mso-bidi-font-style: italic; mso-bidi-font-weight: bold;">

<span style="font-family: "Arial","sans-serif";"> The ability of a building element or building structure to reduce the sound transmission through it. The sound insulation is measured at different frequencies, normally 100-3150 Hz. Airborne sound insulation is expressed by a single value, //<span style="font-family: "Arial","sans-serif";">D // n,c,w, //<span style="font-family: "Arial","sans-serif";">R // w or //<span style="font-family: "Arial","sans-serif";">R' // w. Impact sound insulation is expressed by a single value //<span style="font-family: "Arial","sans-serif";">L // n, w or //<span style="font-family: "Arial","sans-serif";">L' // n,w.
 * <span style="color: black; font-family: "Arial","sans-serif"; font-size: 12.0pt; line-height: 115%; mso-ansi-language: EN-US; mso-bidi-font-style: italic;">Sound insulation ** <span style="color: black; font-family: "Arial","sans-serif"; font-size: 12.0pt; line-height: 115%; mso-ansi-language: EN-US; mso-bidi-font-style: italic; mso-bidi-font-weight: bold;">

<span style="font-family: "Arial","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="color: black; font-family: "Arial","sans-serif"; font-size: 12.0pt; line-height: 115%; mso-ansi-language: EN-US; mso-bidi-font-style: italic;">Sound pressure level (dB) ** <span style="color: black; font-family: "Arial","sans-serif"; font-size: 12.0pt; line-height: 115%; mso-ansi-language: EN-US; mso-bidi-font-style: italic; mso-bidi-font-weight: bold;">

<span style="font-family: "Arial","sans-serif";"> Measured in dB (deciBel). dB is measured at different frequencies. dB(A) (or L pA ) is a single-figure value used to describe the total sound strength for all frequencies in a way similar to the sensitivity of the ear. dB(C) (or L pC ) particularly focuses on low frequencies and better reflects how a sound is perceived by people with impaired hearing.
 * <span style="color: black; font-family: "Arial","sans-serif"; font-size: 12.0pt; line-height: 115%; mso-ansi-language: EN-US; mso-bidi-font-style: italic;">Sound strength (dB) ** <span style="color: black; font-family: "Arial","sans-serif"; font-size: 12.0pt; line-height: 115%; mso-ansi-language: EN-US; mso-bidi-font-style: italic; mso-bidi-font-weight: bold;">

<span style="font-family: "Arial","sans-serif";"> Similar to the RASTI method but a more complete form of measuring speech intelligibility by measuring all octave bands in the frequency range 125-8000 Hz.
 * <span style="color: black; font-family: "Arial","sans-serif"; font-size: 12.0pt; line-height: 115%; mso-ansi-language: EN-US; mso-bidi-font-style: italic;">Speech Transmission Index (STI) ** <span style="color: black; font-family: "Arial","sans-serif"; font-size: 12.0pt; line-height: 115%; mso-ansi-language: EN-US; mso-bidi-font-style: italic; mso-bidi-font-weight: bold;">

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