📄️ EDC
The starting point for the calculation of most acoustic parameters is the EDC curve. An impulse response (IR), $h(t)$, is a response at a receiver to an impulse generated at a source position. This is equivalent to a sound evolution over time measured/registered at the receiver position, when there is a hand clap (ideally infinitesimally short) at the source position. By analyzing the IRs at sufficiently many locations, we can evaluate the global behavior of the room whether it is suitable for the intended purpose. A concert hall needs a certain reverberation for enjoying music, as too dry conditions are not pleasant both for musician and audience. A classroom with too much reverberation can make listeners suffer in understanding what is being said.
📄️ Reverberation Time
The subjective feeling of reverberation is called reverberance, which is best known of all the subjective room acoustic aspects. When a room has too much of this property, speech loses intelligibility because important details, i.e., consonants, are masked by louder, lingering vowels. In music listening condition, however, reverberance adds attractive fullness to the sound by binding adjacent notes and blending sounds from different instruments in ensemble.
📄️ Clarity and Definition
Clarity (C) is an objective parameter measuring early-to-late arriving sound energy ratio. As implied by the name, it aims to quantify how clearly the early arriving sound is perceived with respect to the late part. This parameter can be calculated on an early time limit of 50 ms or 80 ms, respectively targeting conditions for either speech or music [1].
📄️ Centre time
Another acoustic measurement parameter is the centre time, ${T_}$, represents the time of the centre of gravity of the squared
📄️ Strength
Sound strength, G, represents the logarithmic ratio of this sound energy to that of the response measured in a free field at 10 m distance from the sound source. [1]
📄️ Sound Pressure Level
The sound pressure level $\text$ is determined at the receiver position by calculating, for each octave band $i$, the average of the complex pressure $\bar{p}_{i}$ across the band:
📄️ Speech Transmission Index
Speech intelligibility can also be determined by measuring the speech transmission index $$, in addition to ${C{50}}$ and ${D{50}}$, This index can be obtained by using special modulated noise signals or post-processing the impulse response.
📄️ Open Plan Office
Scope