ISO 3382-1:2009 音響—部屋の音響パラメータの測定—パート1：パフォーマンススペース | ページ 6

3.6.1

無人状態

使用のために準備され、スピーカーまたは演奏者と聴衆のために準備ができているが、これらの人が存在しない部屋の状態。コンサートホールやオペラハウスの場合は、できれば演奏者の椅子、譜面台、打楽器などがある.

3.6.2

スタジオ状態

演奏者またはスピーカーのみが占有し、聴衆がいない部屋の状態（例えば、リハーサルまたは録音中）で、演奏者および技術者などの他の人が通常の数に相当する数である状態。

3.6.3

占領状態

座席の80%から100%が占有されているときの講堂または劇場の状態

注記 1:部屋で測定された残響時間は、存在する人数の影響を受けます。上記の占有状態は、測定目的で定義されています。

3.1

decay curve

graphical representation of the decay of the sound pressure level in a room as a function of time after the sound source has stopped

[SOURCE:ISO 354:2003, 3.1]

Note 1 to entry: It is possible to measure this decay either after the actual cut-off of a continuous sound source in the room or derived from the reverse-time integrated squared impulse response of the room (see Clause 5).

Note 2 to entry: The decay directly obtained after non-continuous excitation of a room (e.g. by recording a gunshot with a level recorder) is not recommended for accurate evaluation of the reverberation time. This method ought only be used for survey purposes. The decay of the impulse response in a room is in general not a simple exponential decay, and thus the slope is different from that of the integrated impulse response.

3.2

interrupted noise method

method of obtaining decay curves by direct recording of the decay of sound pressure level after exciting a room with broadband or band limited noise

[SOURCE:ISO 354:2003, 3.3]

3.3

integrated impulse response method

method of obtaining decay curves by reverse-time integration of the squared impulse responses

[SOURCE:ISO 354:2003, 3.4]

3.4

impulse response

temporal evolution of the sound pressure observed at a point in a room as a result of the emission of a Dirac impulse at another point in the room

[SOURCE:ISO 354:2003, 3.5]

Note 1 to entry: It is impossible in practice to create and radiate true Dirac delta functions, but short transient sounds (e.g. from gunshots) can offer close enough approximations for practical measurement. An alternative measurement technique, however, is to use a period of maximum-length sequence (MLS) type signal or other deterministic, flat-spectrum signal like a sine sweep and transform the measured response back to an impulse response.

3.5

reverberation time

T

duration required for the space-averaged sound energy density in an enclosure to decrease by 60 dB after the source emission has stopped

Note 1 to entry: The reverberation time is expressed in seconds.

Note 2 to entry:T can be evaluated based on a smaller dynamic range than 60 dB and extrapolated to a decay time of 60 dB. It is then labelled accordingly. Thus, if T is derived from the time at which the decay curve first reaches 5 dB and 25 dB below the initial level, it is labelled T₂₀. If decay values of 5 dB to 35 dB below the initial level are used, it is labelled T₃₀.