FEATURES:
* Complies with ail existing standards for impulse and
precision sound ievei meters
■ Equipped with individually calibrated, high sensitivity,
precision condenser microphone
« Conical shaped front-end for minimum disturbance of sound
field
« RMS detector with crest-factor capability up to 40
■ Peak detector with 20//S rise time and Hold facility
■ Impulse detector with Max. RMS Hold facility
■ "D", "A", "B", "C" and "Lin" frequency weighting
® 2 Hz or 10 Hz selectable low frequency cut-off
■ Interchangeable meter and attenuator scales facilitate
direct reading of sound and vibration figures
* Performs as Octave or Third-octave
Analyzer with
system-matching
Filter sets
* AC and DC outputs for recorders etc.
* Overload indicators for both input and output amplifiers
* Performs as Vibration Meter or
Analyzer combined with
appropriate
Accessories
■ Wide selection of
Accessories
USES:
■ Noise and Vibration measurements for health protection
* Noise and Vibration
measurements in industry for quality inspection and development
■ Measurement of Shock and Maximum Acceleration
■ Audiometer Calibration,
■ Acoustic Measurements
■ Noise and Vibration Analysis with
Filter Sets Type 1613
and Type 1616
The impulse Precision Sound
Level Meter Type
2209 provides
the sound and vibration analyst with almost everything
desirable in a single, portable measuring instrument. The
A,BandC weighting networks as well as the D weighting
network, intended for aircraft noise measurements, are
built-in. The meter response may be switched to the
standardized Stow, Fast and Impulse time constants, as well
as to indicate the absolute peak value of the measured
signai. The impulse facility of the instrument gives the
feature of being able to measure the maximum of the short
time RMS value of impulsive sounds (1 to 1000 ms) with a
time weighting response in accordance with IEC
Recommandation 179 A. This puts strict requirements to the
RMS detector which is able to handle signals with crest
factors as high as 40 (10 at full scale deflection). The
Peak mode allows objective measurements of signal peaks with
duration as short as 20yus, which is of importance both when
determining noise and when investigating vibration shocks.
Overload indicators in both in- and output amplifiers give
warning of excessive signal levels. To allow frequency
analysis of the measured signal, the instrument is equipped
with in- and output sockets for connection of external
filters. AC and DC outputs give the possibility for
connection of headphones, level recorders, tape recorders etc.
The instrument complies with the requirements of !EC 179 and
179A for precision and impulse sound level meters as well as
DIN 45 633 parts 1 and 2 and ANSI S 1.4-1971 requirements
for Type 1 sound level meters.
It is powered from 3 built-in standard batteries giving it a
continuous operating time of 8 hours. Rechargeable
NiCd-celis giving 14 hours of continuous operation may also
be used. A built-in reference voltage provides easy
electrical calibration of the instrument.
A unique feature of this instrument is its system of 20
interchangeable attenuator scales and its reversible meter
scale, allowing it to be used both as a direct reading
precision sound
Level Meter and as a vibration meter, with a
wide variety of microphone and accelerometer sensitivities.
20 interchangeable scales are supplied covering microphone
sensitivities from 0,4 to , 160mV per Pa and accelerometer
sensitivities from 1 to 285 mV per m/s2 with indication in
both metric and British units. Direct measurement of
vibration velocity or displacement in addition to
acceleration, can be made if an optional Integrator ZR 0020
is employed.
Sound Measurements
As standard, the instrument is equipped with a B&K high
sensitivity, 1/2” diameter free-field Condenser Microphone
Type 4165, giving it a measuring range from 24 to 140dB(A)
and a wide frequency range both in free and diffuse sound
fields, due to its excellent omnidirectivity. The microphone
is delivered with its own individual calibration chart
giving all relevant calibration data and complete frequency
response curve.
directly on the instrument, but should normally be mounted
on the Extension Rod UA 0196, which is included, and which,
together with the conical shaped front-end of the instrument
secures the free-field characteristics required to fulfil
the IEC, DIN and ANSI requirements to precision sound level
meters. If it is desired to remove the microphone even
further from the instrument, use can be made of the standard
Bruei & Kjaer microphone Extension Cables available in
lengths of 3, 10 and 30 metres. The cables are inserted
between the removable input stage and the Sound
Level Meter
and the influence of cable capacitance on calibration can
therefore be neglected. The wide frequency range of the
instrument, from 2 Hz to 70 kHz, together with appropriate
microphones from B & K's wide range, enables measurements
both up in the ultrasonic range and down in the infrasonic
range. If desired, the frequency range can be limited
downwards to 1.0 Hz by a screw switch in the input stage, to
avoid the influence of low frequency pressure variations
which might disturb norma! measurements in the audible range.
A windscreen, which should be fitted over the microphone
when measuring outdoors in order to reduce wind noise, is
included. Also included is an input adaptor, to be fitted
instead of the microphone, allowing direct electrical input,
for instance from accelerometers or hydrophones. ! For
measurement of Noise Dose as described in ISO R1999 and
R1996 the Noise Dose Meter Type 4423 can be connected to the
output.
Use with other Microphones, For
measurement of higher levels and frequencies than is
possible with the 1/2” microphone Type 4165, or if a linear
random incidence microphone response is required, other 1/2"
microphones from the B&K programme can be used directly, for
instance Type 4133, 4134, 4163 or 4166. For measurement of
lower levels, the 1" microphones Type 4145 or 4161 can be
recommended. Adaptors DB 0962 and DB 0375 are available for
fitting these microphones directly onto the input stage or
onto the extension rod.
quirements to omniafrecuvuy,
1" microphones mentioned require the use of a Random
Incidence Corrector UA 0055 instead of the normal microphone
protection grid. For special applications the sound level
meter can be used with other microphones than described
here, and the Product Data Sheet for the B&K microphone
programme should be consulted. See also survey of
Accessories available on page 4, Fig.6,
Vibration Measurements
When the microphone is replaced by the Input Adaptor JJ 2614
(included) and one of the B&K accelerometers is connected,
the instrument functions as a vibration meter, To give
direct reading in vibration units, the meter scale is
reversed and the attenuator scaie which is calibrated to
cover the sensitivity of the accelerometer chosen is fitted
instead of the dB-calibrated scale for sound level
measurement. If required, vibration velocity and
displacement can be measured in addition to acceleration
when an Integrator ZR 0020 is mounted between the
accelerometer and sound
Level Meter. Also in this case,
reading is direct and can be in either British or metric units.
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