B&K 2250 Light Manual do Utilizador descarregar pdf (Página 159)

147

Chapter 14

Reverberation Time Software

(Optional Module)

14.1 Introduction

Reverberation Time Software BZ-7227 enables you to measure reverberation time in

1/1-octave or 1/3-octave.

Check the About screen to see whether you have a license to run Reverberation Time Software.

(To access the About screen, tap the Help icon then tap About.) See Chapter 9 for

instructions on installing a license for Reverberation Time Software.

14.1.1 Definition

Reverberation Time (RT) is the most important parameter describing the acoustic quality of a

room or space. It is important for sound levels, speech intelligibility and the perception of

music. In addition, it is used to correct for the effects of RT on building acoustics and sound

power measurements.

RT is the decay time for sound in a room after the excitation stops. It is the time for a 60 dB

drop in level, but the decay is usually evaluated over a 10, 20 or 30 dB drop, using the

measurements within these ranges to make a regression line, which is then extrapolated to the

60 dB range (Fig.14.1).

RT may be labelled EDT, T20 and T30 respectively for those three evaluation ranges. EDT is

used in room acoustics only, while T20 and T30 may be used for Building Acoustics, Sound

Power and Absorption Coefficient measurements as well.

RT is measured in 1/1- or 1/3-octave frequency bands, some of which may be averaged to

provide a single-number result for the most significant bands.

RT may range from 0.1 seconds (or less) in anechoic chambers, to 10 or more seconds in large

public spaces.

1 2 ... 154 155 156 157 158 159 160 161 162 163 164 ... 331 332

Sem comentários

B&K 2250 Light Manual do Utilizador Página 159