Cirrus CR51 Series User manual

Instrument
Handbook
CR:514 & CR:515
Single-Level Acousc
Calibrator

CR:514 & CR:515 Acoustic Calibrator User Manual
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The content of this manual, any illustrations, technical information and descriptions within this document
were correct at the time of going to print. Cirrus Research plc reserves the right to make any changes
necessary, without notice, in line with the policy of continuing product development and improvement.
No part of this publication may be duplicated, reprinted, stored in a data processing system or transmitted
by electronic, mechanical, photographic or other means, or recorded, translated, edited, abridged or
expanded without the prior written consent of Cirrus Research plc.
No liability is accepted for any inaccuracies or omissions in this manual, although due care has been taken
to ensure that is it complete and accurate as possible.
Accessories supplied by Cirrus Research plc have been designed for use with the instrumentation
manufactured by Cirrus Research plc. No responsibility is accepted for damage caused by the use of any
other parts or accessories.
In order to take account of a policy of continual development, Cirrus Research plc reserves the right to
change any of the information contained in this publication without prior notice.
Produced by Cirrus Research plc, Acoustic House, Bridlington Road, Hunmanby, North Yorkshire, YO14
0PH, United Kingdom.
© Copyright Cirrus Research plc 2022
Reference Number 05/18/CR514&515/08

CR:514 & CR:515 Acoustic Calibrator User Manual
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Operation. .................................................................................................................... 4
Switching on the Calibrator ............................................................................................. 4
Permanent-on Mode ................................................................................................................. 4
Calibrating a Sound Level Meter. ..................................................................................... 5
Background Noise .......................................................................................................... 5
Stabilisation .................................................................................................................. 5
Changing the Battery .................................................................................................... 6
Battery type. ................................................................................................................ 6
Specification. ................................................................................................................ 7
Technical Information .................................................................................................. 8
Free Field Correction .................................................................................................... 9
Microphone Correction Values .................................................................................................... 9
Example ................................................................................................................................. 9
EU Declaration of Conformity ..................................................................................... 10
Type Approval Certification ........................................................................................ 11
Product Guarantee & Extended Warranty ................................................................... 13
Cirrus Research Offices .............................................................................................. 14

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Operation.
Switching on the Calibrator
Press the aPower Button on the end of the Calibrator to switch the unit on. The
Indicator will illuminate to show that the unit is operating.
The calibrator will automatically switch off after 5 minutes to preserve battery power.
To switch off the calibrator manually, press the power button again and the indicator
will extinguish to show that the unit is switched off.
Permanent-on Mode
For some applications there may be a need to have the calibrator switched on
continuously. To allow for this, the calibrator can be turned on by pressing and holding
the power button for three seconds.
Release the button and the indicator will flash to show that the unit is in permanent-on
mode. Press the power button to switch off the calibrator.

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Calibrating a Sound Level Meter.
Push the microphone of the Sound Level Meter into the cavity at the end of the
calibrator. Ensure the microphone is fully inserted into the cavity and is past the ‘O’ ring
seals. The microphone should be parallel to the body of the calibrator. Also ensure that
the small bleed-hole next to the microphone cavity is not blocked as this could cause
damage to the microphone.
Most modern Sound Level Meters have electronic calibration with the level adjusted
automatically. Adjust the Sound Level Meter to the correct level where applicable.
When correcting the value generated by the calibrator a correction for the type of
microphone capsule may need to be applied (see Appendix 2)
Background Noise
In order for the calibrator to operate as intended, the ambient acoustic noise level
should be no greater than 80dBA.
Stabilisation
In order for the sound pressure level and frequency to stabilise after switching the
calibrator on when coupled to a microphone, a period of at least 30 seconds should be
allowed before performing a calibration.

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Changing the Battery
The CR:514 & CR:515 acoustic calibrators use a single 9v alkaline battery. This type of
battery is known as 6F22 or NEDA 1604. It is also commonly known as PP3.
1. Unscrew the screw holding the battery cover on, using a coin.
2. The battery, type 6F22 (PP3) can now be eased out of its holder and replaced.
The battery should be eased out terminal side first by pushing against the spring
at the other end. Ensure that the battery is inserted with the correct polarity
with the negative terminal at the contact with the larger cutout.
Battery type.
The battery should be an alkaline battery, not an ordinary dry cell. The battery is 9
volts when new and will operate the calibrator down to 6.4 volts. When the battery
voltage is below 6.6 volts but above 6.4 volts, the power LED will flash to indicate that
the battery voltage is low. When the battery voltage is below 6.4 volts the calibrator
will not turn on. A discharged battery may allow switch-on but will soon drop in voltage
and indicate low battery or switch off.

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Specification.
Frequency 1kHz ± 1%
Sound Level 94dB re 20μPa
Standardisation CR:514 - IEC 60942:2003 Class 2
CR:515 - IEC 60942:2003 Class 1
Distortion Less than 2%
Operating Humidity 25 to 90% Relative Humidity
Operating Static Pressure 65 kPa to 108kPa
Operating Temperature -10oC to +50oC
Storing Temperature -20oC to +60oC
Effective Volume 6.19 cm3  0.2 cm3
Cavity Diameter 0.525 inch
Battery 1 x 9v 6F22 (Neda 1604)
Battery Life Approx 15 Hours Continuous Use
Battery Voltage 9v Nominal (10v Maximum, 6.4v Minimum)
Weight with Battery 185g
Dimensions 135mm x Ø48mm

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Technical Information
The normal mode of operation of the calibrator is with the unit switched on.
When the LED indicates the unit is switched on this produces the greatest radio
frequency emissions.
The calibrator continues to function after exposure to contact discharges up to 4kV and
air discharges up to 8kV, for both positive and negative voltages relative to earth
ground.
The calibrator conforms to IEC 60942:2003 for a modulated root-mean-square
electromagnetic field strength of 10 V/m.
The maximum susceptibility to power and radio frequency fields is with the cavity facing
away from the emitter with the battery compartment facing the table, the antenna
polarisation horizontal and the calibrator switched on.

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Free Field Correction
When calibrating a microphone which is to be used for free field measurements, a small
correction may be necessary to compensate for the difference between the
microphone's free field response at 'zero degrees' or 'head-on' incidence and the
pressure level generated by the calibrator.
The correction is typically -0.3dB for ½ inch microphones (making the effective
calibration level 93.7dB).
The table below shows the correction values for the standard microphones of Cirrus
Research plc.
Calibration corrections are listed below for the Cirrus Research plc ½" Capsules and
three microphone capsules commonly used in Calibration Laboratories:
Microphone Correction Values
Microphone Type Calibration Correction Effective Calibration Level
MK:202 -0.3dB 93.7 dB
MK:215 -0.3dB 93.7 dB
MK:216 -0.3dB 93.7 dB
MK:226 -0.3dB 93.7 dB
MK:224 -0.3dB 93.7 dB
B&K 4134 0dB 94.0 dB
B&K 4180 0dB 94.0 dB
B&K 4192 0dB 94.0 dB
Example
An example of the procedure used to calculate the value for an MK:224 microphone is
shown below :
Level = 94.0dB + Microphone Correction
Level = 94.0dB + ( -0.3dB)
Level = 93.7dB
Different microphones will have different correction values. Please check the operation
manual for the Sound Level Meter or microphone concerned for details.

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EU Declaration of Conformity
Manufacturer:
Cirrus Research plc
Acoustic House, Bridlington Road
Hunmanby, North Yorkshire, YO14 0PH
United Kingdom
Equipment Description
The following equipment manufactured after 1st January 2017:
CR:514 Acoustic Calibrator
CR:515 Acoustic Calibrator
Along with standard accessories
According to:
EMC Directive 2014/30/EU
Low Voltage Directive 2014/35/EU
RoHS Directive 2011/65/EU
meet the following standards
EN 61000-6-3:2007+A1:2011
Electromagnetic compatibility (EMC). Generic standards. Emission standard for
residential, commercial and light-industrial environments
EN 61000-6-1:2007
Electromagnetic compatibility (EMC). Generic standards. Immunity for residential,
commercial and light-industrial environments
Auxiliary Industry Standards
EN 60942:2003 Sound calibrators
Signed Dated 1st April 2022
Martin Williams
Chief Engineer

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Type Approval Certification

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Product Guarantee & Extended Warranty
1. Every new product is provided with a 12-month no-quibble warranty. This
covers everything we provide against failure, poor workmanship and
accidental damage.
NB - European Union law states a product has to be fit for purpose for 24
months after purchase. This two-year period covers failure and poor
workmanship only.
2. If the product is calibrated by Cirrus Research or an authorised calibration
and service centre, then the initial 12-month warranty is extended by a
further 12 months, with the same conditions, for up to 15 years in total.
3. If a product has not been calibrated annually by Cirrus Research or an
authorised calibrationand service centre, then you may buy back into the
warranty scheme for a small fee, plus the cost of calibration. This can only
be done once during the life of the product.
4. If a microphone capsule fails under warranty and is physically damaged,
we will replace it with a refurbished capsule.
5. If you don’t wish to have a refurbished capsule, then you can trade in your
damaged capsule for a new one, which will incur a fee.

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Cirrus Research Offices
The addresses given below are the Cirrus Research plc offices. Cirrus Research plc also have
approved distributors and agents is many countries worldwide. For details of your local
representative, please contact Cirrus Research plc at the address below. Contact details for
Cirrus Research authorised distributors and agents are also available from the Internet Web site
at the address shown below.
Main Office
Cirrus Research plc
Acoustic House
Bridlington Road
Hunmanby
North Yorkshire
United Kingdom
YO14 0PH
Telephone:
Fax:
E-mail:
Web Site:
[phone]
[phone]
[email protected]m
www.cirrusresearch.com
Germany
Cirrus Research GmbH
Arabella Center
Lyoner Straße 44 – 48
D-60528 Frankfurt
Germany
Tel: [phone]
Fax [phone]
Email:
Web:
[email protected]
www.cirrusresearch.de

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