B&K 2250 Light Bedienungsanleitung PDF herunterladen (Seite 221)

CHAPTER 18

Specifications

209

CORRECTION FILTERS

For Microphone Types 4189, 4190, 4191, 4193, 4950,

4952, 4952+EH-2152, 4955-A, 4964 and 4184-A, BZ-

7227 is able to correct the frequency response to

compensate for sound field and accessories

Broadband Measurements

DETECTORS

A- and C-weighted broadband detectors with F

exponential time weighting

Overload Detector: Monitors the overload outputs of

all the frequency weighted channels

MEASUREMENTS

and L

for Display as Numbers or Quasi-

analogue Bars

MEASURING RANGES

When using Microphone Type 4189:

Dynamic Range: From typical noise floor to max.

level for a 1 kHz pure tone signal, A-weighted: 16.6 to

140 dB

Primary Indicator Range: In accordance with

IEC 60651, A-weighted: 23.5 dB to 122.3 dB

Linear Operating Range: In accordance with

IEC 61672:

• A-weighted: 23.5 dB to 122.3 dB

• C-weighted: 25.5 dB to 139.7 dB

• Z-weighted: 30.6 dB to 139.7 dB

Frequency Analysis

CENTRE FREQUENCIES

1/1-oct. Band Centre Frequencies: 63 Hz to 8 kHz

1/3-oct. Band Centre Frequencies: 50 Hz to 10 kHz

MEASUREMENTS

spectrum for display only

Zeq

spectra sampled at 5 ms intervals

MEASURING RANGES

When using Microphone Type 4189:

Dynamic Range: From typical noise floor to max.

level for a pure tone signal at 1 kHz 1/3-octave: 1.1 to

140 dB

Linear Operating Range: In accordance with

IEC 61260, 1/3-octave:  20.5 dB to 140 dB

Internal Generator

Built-in pseudo-random noise generator

Spectrum: Selectable Pink or White

Crest Factor:

• Pink noise: 4.4 (13 dB)

• White noise: 3.6 (11 dB)

Bandwidth: Follows measurement frequency range

• Lower Limit: 50 Hz (1/3-oct.) or 63 Hz (oct.)

• Upper Limit: 10 kHz (1/3-oct.) or 8 kHz (oct.)

Output Level: Independent of bandwidth

• Max.: 1 Vrms (0 dB)

• Gain Adjustment: –60 to 0 dB

When bandwidth is changed, the level for all bands is

automatically adjusted to comply with the set output

level

Correction Filters for Sound Sources Type 4292,

Type 4295 and Type 4296: Flat or Optimum

Turn-on Time and Turn-off Time: Equivalent to

RT = 70 ms

Repetition Period: 175 s

Output Connector: Output Socket

Control: See Measurement Control

External Generator

Selectable as alternative to internal generator

For controlling external noise generator

Levels: 0 V (Generator off), 4.5 V (Generator on)

Rise-time and Fall-time: 10 s

Control: See Measurement Control

Reverberation Time

EDT, T20 and T30 in octave or 1/3-octave bands

Decays: Measured and stored using averaging time of

5ms

Evaluation Range: 0 to –10 dB for EDT, –5 to –25 dB

for T20 and –5 to –35 dB for T30

Measurement Time: Automatic selection of

measurement time for the decays based on the actual

reverberation time of the room

Maximum Measurement Time: from 2 to 30 s

Averaging: EDT, T20 and T30 measurements can be

averaged (arithmetic averaging or ensemble

averaging)

EDT, T20 and T30 Calculation: From slope in

evaluation range

Slope Estimation: Least squares approximation

Quality Indicators: Quality Indicators with status

information like Overload, Curvature in %, etc.;

extensive list of status information.

Quality indicators are available on reverberation time

spectra for each frequency band, and as overall quality

indicators for each measurement position and for the

total project (room)

Reverberation Time Range: Max. 50 s, min.

0.1 – 0.7 s, depending on bandwidth and centre

frequency

Wide Band Reverberation Time: The arithmetic

average of the Reverberation Time within a selectable

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B&K 2250 Light Bedienungsanleitung Seite 221

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