• Sound Level Meter

Sound Level Meter

for Simple Noise Measurements

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The optimus yellow instruments are a range of state-of-the-art sound level meters that have been designed to meet the very latest standards for noise measurement instruments and provide the highest level of performance possible whilst being simple to setup, use and operate.


  • Simple Noise Level Testing
  • Noise Ordinance Enforcement
  • Community Noise Assessment
  • Fire & Emergency Alarm Testing
  • Machinery Servicing & Maintenance


There are many noise measurement applications where integrated noise levels, such as Leq or LAVG, are not required and where basic noise data such as Sound Level (SPL) or Maximum Sound Level (Lmax) are all that is needed. These applications include simple noise level testing, noise ordinance enforcement and testing of fire and emergency alarms.

The optimus yellow instruments are ideal for these applications and can be upgraded to add further functions, future proofing your investment.

Simple operation to make measurements simple
The instruments will measure every parameter simultaneously so there is no possibility of you setting the wrong function, butt only the most important data is displayed on the screen. Where data logging is fitted, store this information for download to the NoiseTools software.

Key Features

  • Simple operation
  • Simultaneous measurement of all parameters
  • High resolution colour OLED display
  • Latest digital technology
  • Ergonomically designed case
  • 120dB Measurement range
  • Optional Data Logging with VoiceTag audio recording


Data Logging of measured data

The CR:152B and CR:151B instruments provide data logging of over 10,000 records as well as allowing VoiceTag audio information to be stored before each measurement.
These recordings can be played back in the NoiseTools software to provide notes and documentation for each measurement.

A clear upgrade path to protect your investment
A sound level meter should be an investment and the optimus range has been designed with the future in mind.
The units can be upgraded and enhanced as and when new regulations are introduced or when new functions are available.


Applicable Standards
  • IEC 61672-1:2002 Class 1 or Class 2 Group X
  • IEC 60651:2001 Type 1 I or Type 2 I ANSI S1.4 -1983 (R2006)
  • Class 1 Instruments MK:224 pre-polarized
  • Class 2 Instruments MK:216 pre-polarized
Microphone PreamplifierMV:200 Removable Preamplifier
Total Measurement Range:20dB to 140dB RMS Single Range
Noise Floor: <18dB(A) Class 1, <21dB(A) Class 2
Frequency WeightingsRMS: A, C, & Z Measured Simultaneously
Time WeightingsFast, Slow & Impulse Measured Simultaneously
DisplayHigh resolution OLED display with ambient light sensor & illuminated keypad
Memory4GB Expandable with up to 10,000 measurements stored (B Version)
Time History Data Rates
(Global settings)
10ms, 62.5ms, 125ms, 250ms, 1/2 sec, 1 sec, 2 sec (User selectable)
VoiceTag Audio Recording
(B Versions)
30 seconds of audio recording with each measurement
Size283mm x 65mm x 30mm
Weight300gms / 10oz
Batteries4 x AA Alkaline
Battery life
  • Typically 12 hours with Alkaline AA
  • Typically 20 hours with Lithium AA Non-Rechargeable

Battery life is dependent upon the battery type and quality & screen brightness

External Power
  • 5v via USB Socket from PC or Power Supply
  • 5v-15v via MultiIO socket
Tripod Mount1/4” Whitworth socket
ConnectionsUSB Type B to PC
Multi-pin IO for external power
AC Output via 3.5mm Jack Socket & ZL:826 Cable
DC Output via Multi-IO Socket & ZL:825 Cable
CaseMaterial: High Impact ABS-PC with soft touch back & keypad
  • Temperature Operating
    • -10°C to +50°C
    • Storage -20°C to +60°C
  • Humidity
    • Up to 95% RH Non Condensing
Electromagnetic performanceIEC 61672-1:2002 & IEC 61672-2:2003
Except where modified by EN 61000-6-1:2007 & EN 61000-6-1:2007
Language optionsEnglish, French, German, Spanish as standard
Other language options may be available
Software SupportNoiseTools Download, Configuration & Analysis software supplied as standard. Compatible with Microsoft Windows XP, Vista & 7 (32bit & 64bit)

NoiseTools is supplied free from any licensing or installation restrictions.
Measurement Functions
CR:152A & CR:151A
Displayed Functions
Measurement Run Time
CR:152B & CR:151B
Displayed Functions
Measurement Run Time
Stored FunctionsLXYMax & Time History of LXYMax
where x=A ,C ,Z; y= F, S, I

All values, figures and performance statements are typical and are subject to change without notice.

1. For details of the displayed and stored parameters, please refer to the optimus user manual for full specifications.
All specifications, features and values are typical and are subject to change without notice.


FunctionClass 1Class 2Sound Level
Data LoggingVoiceTag
CR:152A YesYes   CK:152A
CR:151AYes Yes   CK:151A
CR:152B  YesYesYesYesCK:152B
CR:151BYes YesYesYesYesCK:151B

Standard Accessories

The optimus sound level meters are supplied, as standard, with the following accessories:

  • User Manual
  • Certificate of Calibration
  • USB Data/Power Cable
  • Windshield
  • NoiseTools Software CD (Requires B Version to download measurements)


Measurement Kits

The optimus sound level meters are available as a complete measurement kit with the following accessories:

  • optimus Sound Level Meter
  • CR:514 Class 2 or CR:515 Class 1 Acoustic Calibrator
  • UA:237 90mm Windshield
  • CK:280 Carrying Case
  • User Manual & Certificates of Calibration
  • USB Data/Power Cable & NoiseTools Software CD (Requires B Version to download measurements)