Acoustics Designการควบคุมปัจจัยต่างๆ ที่มีผลต่อคุณภาพเสียงภายในห้อง เพื่อให้ห้องมีคุณสมบัติเหมาะสมต่อกิจกรรมของห้องนั้นๆ เช่น ค่า RT , NC, %ALcons, STI, Clarity etc. เราจำลองความน่าจะเป็นด้วย software เฉพาะทางเพื่อให้ทราบผลก่อนการสร้าง ช่วยลดการสูญเสียจากงานก่อสร้างและสร้างงานที่ดีได้อย่างที่ควรจะเป็น
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Criteria of Acoustics Design
Reverberation Time (RT)
Reverberation time is a measure of the amount of reverberation in a space and equal to the time required for the level of a steady sound to decay by 60 dB after the sound has stopped. The decay rate depends on the amount of sound absorption in a room, the room geometry, and the frequency of the sound. RT is expressed in seconds. This decay is usually measured over the first 10, 20 or 30 dB and then extrapolated to the full 60 dB range.
Credit: Calculation of the reverberation time. Available at: http://www.sengpielaudio.com/calculator-RT60.htm. Accessed September 18, 2014.
Reverberation time is a measure of the amount of reverberation in a space and equal to the time required for the level of a steady sound to decay by 60 dB after the sound has stopped. The decay rate depends on the amount of sound absorption in a room, the room geometry, and the frequency of the sound. RT is expressed in seconds. This decay is usually measured over the first 10, 20 or 30 dB and then extrapolated to the full 60 dB range.
Credit: Calculation of the reverberation time. Available at: http://www.sengpielaudio.com/calculator-RT60.htm. Accessed September 18, 2014.
Noise Criteria (NC)
Noise criteria (NC) curves can be used to evaluate existing situations by measuring sound levels at the loudest locations in rooms (preferably at user ear height). They can also be used to specify the steady, or continuous background noise levels needed to help achieve satisfactory sound isolation, provided levels are 4 to 5 dB below the NC curve at both the low and high frequencies. Each NC curve is defined by its sound pressure level over eight octave-band center frequencies shown on the following below chart.
Credit: Noise Criteria for Rooms. Available at: http://www.acousticalsolutions.com/noise-criteria-for-rooms. Accessed September 18, 2014.
Noise criteria (NC) curves can be used to evaluate existing situations by measuring sound levels at the loudest locations in rooms (preferably at user ear height). They can also be used to specify the steady, or continuous background noise levels needed to help achieve satisfactory sound isolation, provided levels are 4 to 5 dB below the NC curve at both the low and high frequencies. Each NC curve is defined by its sound pressure level over eight octave-band center frequencies shown on the following below chart.
Credit: Noise Criteria for Rooms. Available at: http://www.acousticalsolutions.com/noise-criteria-for-rooms. Accessed September 18, 2014.
Air velocity at supply and return
When designing a NC rated room, the one detail that most often gets overlooked is the amount of noise generated from the HVAC systems within the rooms.The table right-hand lists supply and returns air velocities in feet per minute for airflow through unobstructed or free openings and their corresponding noise criteria ratings.
In auditoriums, theaters, and other critical listening spaces, the air velocities should below so that the signal-to-noise ratios will be high. The values in the table should be used as rough guidelines for design purposes only when specific data on registers and grilles are unavailable for the air distribution layout, airflow volumes, and pressure drop conditions being evaluated.
Credit: Noise Criteria for Rooms. Available at: http://www.acousticalsolutions.com/noise-criteria-for-rooms. Accessed September 18, 2014.
When designing a NC rated room, the one detail that most often gets overlooked is the amount of noise generated from the HVAC systems within the rooms.The table right-hand lists supply and returns air velocities in feet per minute for airflow through unobstructed or free openings and their corresponding noise criteria ratings.
In auditoriums, theaters, and other critical listening spaces, the air velocities should below so that the signal-to-noise ratios will be high. The values in the table should be used as rough guidelines for design purposes only when specific data on registers and grilles are unavailable for the air distribution layout, airflow volumes, and pressure drop conditions being evaluated.
Credit: Noise Criteria for Rooms. Available at: http://www.acousticalsolutions.com/noise-criteria-for-rooms. Accessed September 18, 2014.
Recommended NC The noise in different types of rooms should not exceed the Noise Criterion limits listed below:
Credit: Recommended Noise Criterion - NC. Available at: http://www.engineeringtoolbox.com/nc-noise-criterion-d_725.html. Accessed September 18, 2014.
Credit: Recommended Noise Criterion - NC. Available at: http://www.engineeringtoolbox.com/nc-noise-criterion-d_725.html. Accessed September 18, 2014.
Articulation Loss of Consonants in % (%ALcons) ← → Speech Transmission Index (STI)
ALcons expresses loss of consonant definition, lower values are associated with greater intelligibility. Zero %ALcons indicates perfect clarity. It is generally assumed that the maximum allowable value for typical paging applications is 10 %, assuming that the environment is relatively free of masking noise. For learning environments and voice warning systems, the desired value is 5 % or less.
Credit: Intelligibility Conversion. Available at: http://www.sengpielaudio.com/calculator-ALcons-STI.htm. Accessed September 18, 2014.
ALcons expresses loss of consonant definition, lower values are associated with greater intelligibility. Zero %ALcons indicates perfect clarity. It is generally assumed that the maximum allowable value for typical paging applications is 10 %, assuming that the environment is relatively free of masking noise. For learning environments and voice warning systems, the desired value is 5 % or less.
Credit: Intelligibility Conversion. Available at: http://www.sengpielaudio.com/calculator-ALcons-STI.htm. Accessed September 18, 2014.
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