Product Data Sheet BRUEL & KJAER/BRUEL KJAER 4231

User Manual: BRUEL & KJAER/BRUEL & KJAER 4231 Product Data

Open the PDF directly: View PDF .
Page Count: 4

Brüel & Kjær

BK

7/6-'89

Product Data

bility and independence of variations

in static pressure and temperature

around the 1 kHz calibration frequen-

cy. The result of this is a user-friendly

calibrator where exact fitting of the

microphone is non critical and the ef-

fects of changes in temperature and

static pressure are negligible.

The calibrator gives a continuous

sound pressure level when fitted on

a microphone (see Fig. 2) and activat-

ed. The sensitivity of the sound meas-

uring equipment can then be

adjusted until it indicates the correct

sound pressure level. The calibrator

is automatically switched off when

removed from the microphone.

A leather protecting case, which

does not need to be removed to use

the calibrator, is supplied.

The Sound Level Calibrator Type

4231 is a pocket-sized, battery oper-

ated sound source for quick and di-

rect calibration of sound level meters

and other sound measuring systems.

It fits Brüel & Kjær 1″ and 1/2″ micro-

phones and, with adaptors, it can be

used for 1/4″ and 1/8″ microphones as

well.

The calibration frequency is

1000 Hz (the reference frequency for

the standardized international

weighting networks), so the same cal-

ibration value is obtained for all

weighting networks (A, B, C, D and

Linear). The calibration pressure of

94 ±0.2 dB re 20 µPa is equal to 1 Pa

or 1 N/m2. The +20 dB level step gives

114 dB SPL which is convenient for

calibration in noisy environments.

The design of the 4231 is based on

a feed-back arrangement to ensure a

highly stable sound pressure level

and ease of use. The feed-back loop

uses a condenser microphone (see

Fig.1), which is specially developed

for this purpose. This microphone is

optimised to have extremely high sta-

The Sound Level Calibrator Type

4231 is a handy, portable sound source

for calibration of sound level meters

and other sound measurement equip-

ment. The calibrator is very robust and

stable and conforms to IEC 942 Class

1 and ANSI S1.40-1984.

Sound Level Calibrator — Type 4231

FEATURES:

❍Conforms to IEC 942 (1988) Class 1 and ANSI

S1.40–1984 (R 1997)

❍Robust pocket-size design with highly stable level

and frequency

❍Calibration accuracy ±0.2 dB

❍94 dB SPL, or 114 dB SPL for calibration in noisy

environments

❍Extremely small influence of static pressure

❍Sound pressure independent of microphone

equivalent volume

❍1 kHz calibration frequency for correct calibration

level independent of weighting networks

❍Fits Brüel & Kjær 1″ and 1/2″ microphones (1/4″ and

1/8″ microphones with adaptor)

❍Switches off automatically when removed from the

microphone

USES:

❍Calibration of sound level meters and other sound

measurement equipment

2

Fig.2 Type 4231 fitted to 2238 Mediator.

The calibrator’s centre of gravity is posi-

tioned very close to the microphone, giving

a stable set-up

Fig.1 Cross-sectional view of Sound Level Calibrator Type 4231. The feed-back loop is

based on a high-quality condenser microphone to ensure a very stable sound pressure level

930129e

Reference MicrophoneLoudspeaker

Pressure Equalization Channels

Circuit Board

Battery

Lid

Microphone to be calibrated 1/2" Adaptor

bp1311141.fm Page 2 Monday, December 6, 1999 10:03 AM

Black process 15,0° 153,0 LPI

3

Specifications 4231

Ordering Information

Brüel&Kjær reserves the right to change specifications and accessories without notice

STANDARDS SATISFIED:

IEC 942 (1988), Sound Calibrators, Class 1

ANSI S1.40–1984 (R 1997), Specifications for

Acoustic Calibrators

NOMINAL SOUND PRESSURE LEVEL:

94.0 dB ±0.2 dB or 114.0dB ±0.2 dB re 20µPa

at reference conditions

FREQUENCY: 1kHz

±0.1%

SPECIFIED MICROPHONE TYPES:

(Conforms to IEC 942 Class 1)

Brüel &Kjær (and similar types) 1″ and 1/2″, 1/4″,

1/8″ with adaptors

EQUIVALENT FREE-FIELD LEVEL:

(0° incidence, re Nominal Sound Pressure Level)

–0.15dB for 1/2″ Brüel &Kjær Microphones. See

the 4231 User Manual for other microphones

EQUIVALENT RANDOM INCIDENCE LEVEL:

(re Nominal Sound Pressure Level)

+0.0 dB for 1″, 1

/2″, 1/4″ and 1/8″ Brüel &Kjær

Microphones.

NOMINAL EFFECTIVE COUPLER VOLUME:

>200cm3 at reference conditions

TOTAL HARMONIC DISTORTION (THD): <1%

LEVEL STABILITY:

Stabilization Time: 5s

Short-term: Better than 0.02 dB (as specified in

IEC 942)

1 Year: Better than 0.05 dB

REFERENCE CONDITIONS:

Ambient Temperature: 20°C (68°F)

Ambient Pressure: 1013 hPa

Ambient Humidity: 65% RH

Load: Microphone Type 4134 (effective load vol-

ume: 0.25 cm3)

Environmental

AMBIENT CONDITIONS:

Pressure: 650 to 1080 hPa

Humidity: 10 to 90% RH (without condensation)

Effective Load Volume: 0 to 1.5 cm3

INFLUENCE OF AMBIENT CONDITIONS:

Temperature Coefficient: ±0.0015 dB/°C

Pressure Coefficient: +8×10–5 dB/hPa

Humidity Coefficient: 0.001 dB/%RH

Power Supply

Batteries: 2×1.5 V IEC Type LR6 (“AA” size)

Lifetime: Typically 200 hours continuous oper-

ation with alkaline batteries at 20°C (68°F)

Check: When the calibrator can only be oper-

ated by keeping the On/Off button continuously

pressed the batteries should be changed.

Dimensions and Weight:

Height: 30 mm (1.2″)

Width: 72mm (2.8″)

Depth: 72 mm (2.8″)

Weight: 150 g (0.33 lb.), including batteries

Note: All values are typical at 25°C (77°F), un-

less measurement uncertainty or tolerance field

is specified. All uncertainty values are specified

at 2σ (i.e. expanded uncertainty using a cover-

age factor of 2)

Type 4231 Sound Level Calibrator

Includes the following accessories:

KE 0317: Leather Case

2×QB 0013: Alkaline Batteries Type LR6

UC 0210: Adaptor for 1/2″ microphones

Optional Accessories

DP 0775: Adaptor for 1/4″ microphones

DP 0774: Adaptor for 1/8″ microphones

DP 0682: Adaptor for Studio Microphones

Types 4003 and 4006

DP 0750: Adaptor for Studio Microphones

Types 4004 and 4007

DP 0887: Adaptor for Head and Torso

Simulator Type 4128

DP 0888: Adaptor for Intensity Probe Sets

Types 3545, 3548, 3583, 3584

COMPLIANCE WITH STANDARDS:

CE-mark indicates compliance with: EMC Directive.

Safety EN 61010–1 and IEC 1010–1: Safety requirements for electrical equipment for

measurement, control and laboratory use.

EMC Emission EN 50081–1: Generic emission standard. Part 1: Residential, commercial and

light industry.

EN 50081–2: Generic emission standard. Part 2: Industrial environment.

CISPR 22: Radio disturbance characteristics of information technology

equipment. Class B Limits.

FCC Rules, Part 15: Complies with the limits for a Class B digital device.

EMC Immunity EN 50082–1: Generic immunity standard. Part 1: Residential, commercial and

light industry.

EN 50082–2: Generic immunity standard. Part 2: Industrial environment.

Temperature IEC 68–2–1 & IEC 68–2–2: Environmental Testing. Cold and Dry Heat.

Operating Temperature: −10 to +50°C (14 to 122°F)

Storage Temperature: –25 to 70°C (–13 to 158°F)

Humidity IEC 68–2–3: Damp Heat: 90% RH (non-condensing at 40°C (104°F))

Enclosure IEC 529 (1989): Protection provided by enclosures: IP50

bp1311141.fm Page 3 Monday, December 6, 1999 10:03 AM

Black process 15,0° 153,0 LPI

HEADQUARTERS: DK-2850 Nærum · Denmark · Telephone: +4545800500 · Fax: +4545801405 · http://www.bk.dk · e-mail: info@bk.dk

Australia (02)9450-2066 · Austria 0043-1-8657400 · Brazil (011)5182-8166 · Canada (514)695-8225 · China (86) 1068029906

Czech Republic 02-67021100 · Finland (0)9-755 950 · France (01)69906900 · Germany 06103/908-756 · Hong Kong 25487486 · Hungary (1)2158305

Ireland (01) 450 4922 · Italy 0257 68061 · Japan 03-3779-8671 · Republic of Korea (02)3473-0605 · Netherlands (31)318 559290 · Norway 66771155

Poland (22)858 9392 · Portugal (1)4711453 · Singapore (65) 377-4512 · Slovak Republic 421 7 544 307 01 · Spain (91)3681000 · Sweden (08)4498600

Switzerland 01/9436070 · Taiwan (02)7139303 · United Kingdom (0181)954-2366 · USA 18003322040

Local representatives and service organisations worldwide

Brüel & Kjær

BK

7/6-'89

BP 1311 –14 99/11