Brüel & Kjær 4231 Calibrator
Manufacturer:
Model:
4231
Date:
2011
Class:
Type:
SubType:
Sound Level Calibrator
Information
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
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.
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-
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.
Manual type:
Datasheet
Pages:
4
Size:
624.04 Kbytes (639017 Bytes)
Language:
english
Revision:
Manual-ID:
BP 1311-14
Date:
2011 09 01
Quality:
Electronic document, no scan, very well readable.
Upload date:
2017 06 01
MD5:
55cba8635dcd5f498b842c633a60cfa8
Downloads:
649
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