Larson Davis CAL150 User Manual

CAL150

Precision Acoustic Calibrator

Manual

I150.01 Rev E

Larson Davis

CAL150

Manual

Copyright

Copyright 2006-2015 by PCB Piezotronics, Inc. This manual is copyrighted, with all rights reserved.
The manual may not be copied in whole or in part for any use without prior written consent of PCB
Piezotronics, Inc.

Trademarks

PCB® is a registered trademark of PCB, Inc.

Disclaimer

The following paragraph does not apply in any state or country where such statements are not
agreeable with local law:

Even though PCB Piezotronics, Inc. has reviewed its documentation, PCB Piezotronics, Inc. makes no
warranty or representation, either expressed or implied, with respect to this instrument and
documentation, its quality, performance, merchantability, or fitness for a particular purpose. This
documentation is subject to change without notice, and should not be construed as a commitm ent or
representation by PCB Piezotronics, Inc.

This publication may contain inaccuracies or typographical errors. PCB Piezotronics, Inc. will
periodically update the material for inclusion in new editions. Changes and improvements to the
information described in this manual may be made at any time.

Recycling

PCB Piezotronics, Inc. is an environmentally friendly organization and encourages our customers to

be environmentally conscious. When this product reaches its end of life, please recycle the product
through a local recycling center or return the product to:

PCB Piezotronics, Inc.
Attn: Recycling Coordinator
1681 West 820 North
Provo, Utah, USA 84601-1341

where it will be accepted for disposal

Product Warranty

For warranty information, refer to our Terms and Conditions of Sale on our website at

www.larsondavis.com/TermsConditions.aspx.

CAL150 Technical Reference Manual Introduction 1-1

CHAPTER

1

Introduction

This chapter describes the features and accessories of the
Larson Davis CAL150 Sound Level Calibrator.

Features

The Larson Davis CAL150 Sound Level Calibrator is a
battery-operated precision microphone calibrator used for
the calibration of sound level meters and other sound
measurement equipment. It can provide an output level of
either 94.0 or 114.0 dB (switch-selectable) at a frequency of
1 kHz. It has been designed for both field and laboratory use
and the accuracy has been calibrated to a reference traceable
to the National Institute of Standards and Technology.

The Larson Davis CAL150 Sound Level Calibrator has the
following features:

• Class 2 sound level calibrator

• Dual output levels: 94.0 dB and 114.0 dB (user
selectable)

• Output frequency 1 kHz

• Internal batteries for portable operation

• Opening for use with 1/2” microphones

Accessories

• Adaptor ADP031 included for use with 3/8”
microphones

• Adaptor ADP024 available for use with 1/4” microphone

CAL150 Technical Reference Manual Features 1-2

CAL150 Technical Reference Manual Using the CAL150 Calibrator 2-1

CHAPTER

2

Using the CAL150

This chapterr describes the setup and operation of the
CAL150.

Installing the Battery

The CAL150 uses a nine-volt battery and it is recommended
that you use an alkaline battery to extend the running time of
your calibrator. The CAL150 will run for approximately 100
hours on one nine-volt battery when using the 114 dB output
level. This will give you nearly 4200 calibrations.

Follow the steps below to install the battery:
Step 1 Slide the batt ery door on the lower section of the

back panel up to remove it.

Step 2 Gently pul l the batt ery connector clip sufficiently

outside the interior to permit it to be snapped onto
the battery terminals.

Step 3 Tuck the battery, with the battery connector clip

attached, into the battery compartment.

Step 4 Slide the battery door back into place, pressing

until the tab snaps the door securely shut.

Microphone Calibration

The CAL150 provides a nominal tone of 1 kHz, which
requires no weighting filter corrections when used with
sound level meters utilizing A, B, C or Z (Flat) frequency
weighting.

Selecting the Output Level

The output level is user-selected to be 94.0 or 114.0 dB
using the slide selector on the side of the CAL150 . Slide the
switch to lower position for 114.0 dB or to the upper

CAL150 Technical Reference Manual Microphone Calibration 2-2

position for 94.0 dB, as indicated by the label on the lower
left of the front panel.

Calibrating with ½" Free-Field Microphone Corrections

The CAL150 provides a nominal pressure level of 94 dB or
114 dB. The exact levels are printed on the Larson Davis
calibration sheet that comes with the calibrator. When using
a free-field microphone, the pressure level at the microphone
diaphragm will be slightly different. Thus, a free field
correction of -0.12 dB should be applied to either of these
levels. Pressure and random incidence microphone do not
require a correction of this type.

If the calibrator and instrument are near room temperature
(23

°C) and near sea level (101.3 kPa) then no other corrections

need to be made. If the calibration sheet for the CAL150 indicates

113.98 dB for its level when set up to 114 dB then set the Cal Level

in the instrument to 113.86 dB and 1 kHz.

When the microphone and instrument are at a temperature
other than near room temperature or static pressures not near
sea level, then corrections will need to be added for the
ambient temperature and the prevailing static pressure.

Check the calibration data shipped from Larson Davis with
the CAL150 to get these corrections. The corrections can be
added to get the actual level of the CAL150.

The microphone's sensitivity varies with static pressure. If
the instrument is calibrated in one environment and moved
to another, then the sensitivity will change (after
stabilization) depending on the change of temperature and
pressure. The coefficient of static pressure is typically -

0.013 dB/kPa for PCB ½" free-field microphones. If the

system is calibrated at 85 kPa, for instance, then it will be

0.21 dB less sensitive at sea level. The sensitivity of the

microphone varies slightly with temperature also. The
coefficient of temperature is typically -0.009 dB/

°C for PCB
½" free-field microphones. If the system is calibrated at 18 °C then
it will be 0.05 dB less sensitive at 23 °C.

CAL150 Technical Reference Manual Microphone Calibration 2-3

Performing the Calibration

To calibrate the microphone, follow these steps:
Step 1 Place the instrument so that you can perform the

calibration vertically, as shown in Figure 2-1.

WARNING! Do not remove the
microphone gridcap during
calibration as this may damage the
microphone.

Step 2 Insert the proper microphone adapter fully into the

calibrator. Make sure it fits snugly.

Step 3 Insert the microphone fully into the adapter. Make

sure it fits snugly.

The preferred metho d for calibrating
with the CAL150 is to mount the
preamplifier in a fixed, vertical
position.

FIGURE 2-1 Vertical Positioning

Top: calibrator stands
vertically above mounted
preamplifier.

Bottom: mounted
preamplifier,
fixed vertically

CAL150 Technical Reference Manual Microphone Calibration 2-4

Step 4 With the microphone connected to the instrument

being calibrated, press the CAL150’s ON button.
With a fresh battery, the calibrator will issue a tone
for more than 60 seconds before automatically
shutting off (see note below).

Step 5 Make a reading. If the reading is not with in

tolerance, refer to the instrument’s manual for
instructions on how to adjust the instrument.

Step 6 Check the ambient noise level to insure that the

calibration was not influenced by noise from
external sources. The CAL150 needs to be on the
microphone but with the CAL150 signal off.
External noise levels lower than 89 dB SPL for the
114 dB level calibration, and 69 dB SPL for the 94
dB calibration level will influence the calibration
by less than 0.015 dB.

As the battery becomes weaker, the calibration tone will not
deteriorate, but the operating time will decrease until the
time is too short to accomplish an adequate calibration.

Each time the ON button is pressed,
the CAL150 will run approximately
60 seconds on a fresh battery. Do not
press the ON button again to turn it
off. Wait until the calibrator times
out. It is not an ON/OFF button.

When making a sequence of measurements, a calibration
check and an adjustment (if necessary) of the instrument
should be made at the beginning. At the end of the
measurement sequence, the calibration should be checked
again. The inaccuracy of the measurements will be at least
as large as the difference between the level measured for the
initial calibration (or calibration check) and the level
measured for the final calibration check.

Calibration History

Larson Davis strongly recommends that a history of each
calibration adjustment be kept for each piece of equipment.
Normally, most modern equipment requires little or no
adjustment once the initial calibration is performed.
Systematic drifts are possible, and these should be recorded
for corrective action.

Most Larson Davis sound level meters keep a history of each
calibration change that can be printed before an overall reset.
Please refer to the respective instrument manuals for details.

CAL150 Technical Reference Manual Microphone Calibration 2-5

Environmental Precautions

While the CAL150 will perform normally under a wide
variety of gradually changing environmental conditions,
some precautions should be taken when sudden changes
occur:

• The temperature of the CAL150 should be stable. If the
temperature changes suddenly, provide a stabilization
time of at least 15 minutes. This will ensure that the
temperature compensation sensors are at the same
temperature as the rest of the unit.

• While humidity will not affect the CAL150, avoid
condensing moisture. Also, avoid environments over
90% relative humidity because condensation can easily
take place.

• The CAL150 is insensitive to magnetic fields. However,
the instrument being tested may not be. Therefore,
calibration should not be done near motors, dynamos,
high voltage wires, or other sources of electromagnetic
fields.

Calibrator Calibration

The American National Standards Institute states, “An
acoustical calibrator should be recalibrated at least annually
by the instrument manufacturer or an acoustical test
laboratory qualified to perform calibration.” (American
National Standards Institute. Specifications for Acoustical
Calibrators. ANSI S1.40, 2006,par. 5.2)

Larson Davis believes the frequency of recalibration
depends on the number of calibrators being used and the
number of instruments being calibrated. With this in mind,
the following guidelines are presented for your
consideration:

• For one calibrator and one measurement instrument , the
CAL150 should be certified at least yearly.

CAL150 Technical Reference Manual Microphone Calibration 2-6

If a systematic drift of several dB
occurs, there is no reliable way to
verify which instrument is at fault,
even though it is more likely to be the
measurement instrument.

• For one calibrator and several measurement instruments,
one calibration a year is recommended. But if no
systematic drift occurs, every two years might be
satisfactory.

• For several calibrators and several instruments, one
calibration a year is recommended.

If the CAL150 is being used to calibrate several instruments,
then the history of calibration adjustments can usually
pinpoint which instrument is drifting. If all the measurement
instruments are drifting in the same direction b y an amount
you consider significant, the CAL150 should be recertified.

If several instruments and several calibrators are in use, then
the history of calibration adjustments would precisely
pinpoint any problem pieces of equipment. Furthermore, it is
probably satisfactory to recalibrate only one of the
calibrators each year.

CAL150 Technical Reference Manual Specifications A-1

APPENDIX

A

Specifications

The specifications contained in this chapter are subject
to change without notice. Please refer to calibration and
test results for data on a specific unit.

Standards Met

• ANSI S1.40-2006, Specifications and Verification Proce­dures for Sound Calibrators, Class 2

• IEC 60942-2003, Class 2, Sound Calibrators

• IEC 61010-1:2001, Safety requirements for electrical
equipment for measurement, control, and laboratory use

- Part 1 General Requirements

• IEC 61326-1:2005, Electrical equipment for measure­ment, control, and laboratory use - EMC requirements

Technical Specifications

Calibration sound pressure level
(factory specification)

Calibration sound pressure level after one
year

94.0 dB and 114.0 dB ±0.3 dB SPL
re: 20Pa @ 101.3 kPa, 23º C and 50 % RH
(114.0 dB is the principal sound pressure level)

114.0 dB ± 0.3 dB under same conditions as above

Equivalent free-field level -0.12 dB for 1/2” free-field microphones

Frequency 1 kHz ± 1%

Harmonic distortion < 2 %

Stability after pressing On ± 0.1 dB after 2 seconds

Minimum stabilizing time after the
microphone and calibrator are coupled
together

10 seconds

Static pressure range 65 kPa to 108 kPa, SPL variation will be < ± 0.4 dB

A-2 Technical Specifications CAL150 Technical Reference Manual

Table A-1 CAL150 Specifications

Microphone Types According to IEC 61094-4:1995

1/2” WS2P, WS2F and WS2D microphones; no adaptor
required

Temperature range SPL variation < ± 0.6 dB Frequency variation < ± 2 Hz

over the range of -10 ºC to 50 ºC

Humidity range SPL variation < ± 0.5 dB over the range 10 % to 90 %

relative humidity (non-condensing)
Frequency variation < ± 2 % over the range 10 % to
90 % relative humidity (non-condensing)

Storage temperature -40 ºC to 60 ºC

Storage humidity 0 % to 90 % relative humidity (non-condensing)

Effective volume of calibrator and
microphone

4.15cm

3

(0.253 in.3 )

Dimensions Length 106.1 mm (4.18 in.)

Width 63.4 mm (2.5 in.)
Thickness 25.9 mm (1.02 in.)

Weight 156 gm. (5.5 oz.)

Battery 9 V NEDA 1604A or IEC 6LR61. With sufficient battery

voltage, calibrator will run (after releasing ON button)
for 1 to 1.5 minutes before automatic shutdown. With
insufficient battery voltage, calibrator will not remain
ON after release of button

Battery Voltage Operating Range 6.7 Volts to 10 Volts

Traceability Utilize a 1/2” precision condenser microphone (WS2P)

in conjunction with other traceable measuring
instruments to establish traceability of the output level
and frequency of the Model CAL150

CE-mark indicates compliance with EMC directive

Note: The reference orientation for testing the effects of
radio-frequency fields is with the radio-frequency
incident on the calibrator face and the electric field
vector parallel to the axis of the microphone. This is also
the orientation of maximum susceptibility and emissions

CAL150 Technical Reference Manual Technical Specifications A-3

1/4” WS3P, WS3F and WS3D microphones with ADP024
adaptor

According to IEC 61094-1;2000

1/2” LS2P; no adaptor required

Other Microphones

3/8” with ADP031 adaptor

4180 Microphone

The CAL150 level correction is +0.26 dB

A-4 Technical Specifications CAL150 Technical Reference Manual

CE Mark Declaration of Conformity

FIGURE A-1 CE Mark Declaration of Conformity

•PCB

Declaration

of Conformity

Application

of

Council

Directives:

2004/108/BC

EMC

Directive

and

2006/95/EC

Low

Voltage

Directive

Standards

to

which

Conformity

is

Declared:

C€

CE

- Mark indicates compliance

with

EMG

directive and

Low

Voltage

directive

2006/95/EC.

Harmonised

Standards

61326-1:2005

Electrical equipment for

measurement,

control,

and laboratory use - EMC requirements.

Safety requirements for electrical equipment for measurement, control, and

laboratory

use -

Part

1: General requirements.

Product
Specific

standards

60942:2003

Sound Calibrators.

ANSI

.40-2006

Specifications

and

Verification Proceedures for

Sound

Calibrators.

Emissions

Test

Standards

CISPR

11: 4.1

2004:

Industrial, scientific

and

medical (ISM) radio-frequency

Electromagnetic

disturbance characteristics - Limits and methods of

measurement.

Class B, Group 1.

Immunity

Test

Standards

EC

Electrostatic discharge (ESD) immunity.

±4

kV contact discharges and ±8 kV air discharges.

Immunity

Test

Standards

Radiated, radio-frequency, electromagnetic field immunity.

80

1 V/m.

Immunity

Test

Standards

610004-8:2001

Power frequency magnetic

field

immunity. 80

A/m.

50/60

Hz.

Notes:

above are guaranteed only

when

using accessories listed

in

the product manual.

Manufacturer

PCB Piezotronics

3425

Walden Avenue

Depew,

New York USA

Authorized
European
Representative

PCB

Piezotronics Europe
GmbH
Porschestrasse

20-30

41836

Type

of

Equipment:

CAL150

-

Acoustic

Calibrator

the

undersigned,

hereby

declare

that the equipment specified

above

conforms

to the

above Directive(s)

and Standard(s).

Signature:

Name:

Kenneth

J.

Gonyea

Jr.

Title:

V.P.

Manufacturing

PS078(E)

03/13/2015

Depew,

NY

9001

PCB

Piezotronics,

Inc.

Plione:

716-684-0001

FAX:

716-684-0987