重起 在 2004-2-22 15:48:49 发表的内容 如不涉及商业秘密能告知天下,真是功德无量。 |
OK buddies, I have attached here is the absorption coefficient chart for
different materials, thought not all of them yet are rather common at home.
Th Absorption Coefficient is a measure of the quantity of sound lost on a
surface. It can be defined as,
1 - (reflected sound energy) / (incident sound energy)
However, please also note that it is a property of the material on which the
sound impinging and is dependant on thickness of material and frequency
of the sound.
Absorption Coefficient is used to calculate the reverberation time known
as the RT60.
RT60 is the measure of amount of time, in seconds, for reverb to decay
60db below the initial value.
Predictions are based on using unknown surface materials and their
absorption coefficients, calculated in 1-octave frequency bands using
SABINE equations.
The table I attached here show the numbers for an untreated space.
Through design and treatment, the preferred RT60 should fall between
0.35 - 0.5 seconds for each band, matching as close as possible.
Calculating the RT60 is a time consuming work and I do not recommand
you guys to learn to work on this but just in the hope you guys will
at least understand what is Absoption Coefficient and the meaning of
RT60.