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CEL632C Occupational Sound Level Meter with 1/3 Octaves

CEL632C Sound Level Meter
CEL632C Sound Level Meter

Price List

£3328.00 +VAT
Type 2 Occupational Sound Level Meter with 1/3 Octaves
In stock

£3808.00 +VAT
Type 2 Kit with meter, calibrator and case
In stock
£3984.00 +VAT
Type 1 Occupational Sound Level Meter with 1/3 Octaves
In stock

£4775.00 +VAT
Type 1 Kit with meter, calibrator and case
In stock

The delivery price is calculated during checkout based on your location and the goods ordered. Our basic delivery prices are:

Delivery within United Kingdom: £12.00 +VAT

Delivery Service: Next working day*

* For products that are in stock and the order received by midday.

Some products go through a final configuration and calibration before being shipped. If the calibration labs are busy this can add up to two days on to the delivery schedule but guarantees a fresh calibration.

£3328.00 +VAT
Type 2 Occupational Sound Level Meter with 1/3 Octaves
In stock

£3808.00 +VAT
Type 2 Kit with meter, calibrator and case
In stock


  • Real-Time Octave and 1/3 Octave Band Filters
  • Data Logging with detailed Time History store
  • Voice Notes and Audio Recording
  • Automatic On/Off Timers
  • Measures Lavg, TWA, Leq, Lepd, Min, Max, etc. Simultaneously
  • Range: 20 to 140 dB(A)
  • Data Markers


  • Occupational Noise Measurements
  • Hearing Protector Checks
  • OSHA, MSHA, ACGIH, European and other occupational noise regulations


The CEL632C is a data logging sound level meter for detailed occupational noise surveys. It includes automatic timers and a Time History store, making it ideal for longer term and unattended measurements. The real-time octave band filters provide the measurements for a detailed check of hearing protector suitability, and 1/3 octave band filters give a more detailed frequency analysis of machinery noise.

The CEL632C Sound Level Meter measures all the parameters needed for a successful survey of workplace noise. The main parameters - Lavg, Leq, Peak, Lmax, Fast, Slow, etc. - are all measured simultaneously, so there is no need to choose before starting the measurement. With a single span from 20 to 140dB, there is also no need to choose the measurement range either.

Octave Band and 1/3 Octave Band Filters

Rea-time Octave and 1/3 Octave Band Filters are included with this meter. Octaves are particularly useful for assessing the suitability of hearing protectors for a given noise, especially when very high sound levels are present. The CEL632C measures in all bands at the same time as these are "real-time" filters. In 1/3 Octave Band mode, the meter splits the spectrum up into smaller bands (three for each octave) for a more detailed analysis of the spectrum.

Data Logging and Software

The CEL632C comes complete with data logging capability with measurements stored in the meter's large internal memory.


When connected to a Windows computer using the free CasellaDrive software, the meter acts like a memory stick (shows as a removable drive) so the measurements can be loaded into a spreadsheet or moved to your hard drive for long term storage. There is no need to buy special software.


Due to the large amount of data and the potential complexity of the measurements, we would recommend the use of the Insight software. It simplifies the process of downloading the measurements and stores them in a database, managed by person, place or process criteria. The Insight software is included with the sound level meter.


The CEL632C has many applications but is primarily intended for the detailed analysis of noise in the workplace.

  • OSHA Occupational noise regulations (most common in USA)
  • MSHA, ACGIH noise regulations
  • Canadian occupational noise (both 3dB and 5dB exchange rates)
  • European noise at work regulations
  • Machinery testing
  • Hearing protector assessments (NNR, SNR, HML or Octave Band methods)
  • Detailed analysis of noise - time history and frequency content

The occupational noise regulations around the world usually specify or recommend the use of an Integrating sound level meter as this removes the potential error when trying to average it by eye.

The CEL632C takes this one step further, offering a detailed Time History store that provides graphs of the sound level against time. The meter can be left in a noisy environment and downloaded later. The graphs clearly show the noisier and quieter times of day, making the planning of a worker's noise exposure possible.

It also measures in the 1/3 Octave Bands at the same time, offering even more information about the noise in the workplace.

Occupational Noise

The OSHA occupational noise regulations state that you should use at least a Type 2 Sound Level Meter. The meter should be verified by a suitably equipped laboratory when new and we recommend having it checked at least every two years. You also need a Calibrator to check the meter's function before making measurements.

An Integrating meter like the CEL632 provides you with the measurement of the average Slow sound level - Lavg. Rather than trying to average the sound level by eye (made more difficult by the logarithmic nature of noise), the meter does the averaging for you. The Lavg is then used to calculate the worker's Time Weighted Average (TWA) noise exposure.

Hearing Protection Assessment

When the noise levels are particularly high (e.g. greater than 95 dBA) then you should check that the hearing protection provided is adequate. If it does not reduce the noise at the ear to an acceptable level then clearly it is not adequate. The CEL632C measures both the A and C weighted sound level, so you can use the NRR or HML method - for a working example of NRR and HML methods please take a look at our Hearing Protection Calculator.

For a more detailed analysis of hearing protection, particularly when tonal noise is involved, an Octave Band analysis may be required. The CEL632C makes octave band measurements at the same time as all the other broadband measurements, so this information is always available for a more detailed analysis.

Noise Source Identification

Unattended noise measurement is convenient but causes problems when the time comes to identify the source of the noise. Was it a piece of machinery, a steam leak, a vehicle passing or somebody shouting. The CEL632 can record the audio so that you can listen to the interesting bits, enabling you to make a positive identification of the noise source.

Environmental and Community Noise

As the CEL632C is available as either Type 1 or Type 2 and includes data logging, it is suitable for many environmental noise surveys. For more options for this type of application please visit our Environmental Noise page.

Occupational Noise

The CEL632C was designed specifically for occupational noise measurements in line with the OSHA, MSHA, ACGIH and EU regulations. It provides all the noise measurement parameters that you need in a meter of the correct grade, and also offers more detailed data logging and automatic timers for longer term detailed assessments.

This meter can be used without a computer, reading the measurements from the screen, but really benefits from having the Insight software to download the detailed time history measurements.

  • Designed for occupational noise regulations
  • Meets the required standards
  • All parameters needed: Lavg, TWA, LAeq, LPeak
  • Storing and download to computer
  • Detailed time history
  • Color coded display for ease of use

The full occupational noise measurement process is described below.

1. Calibration Check

The regulations and guidelines state that the meter's calibration should be checked before making measurements, and that you should keep records of these calibration checks.

Fit the Calibrator over the microphone and switch it on. The meter automatically detects the presence and correct fitting of the Calibrator and then starts the calibration process, which only takes a few seconds.

Calibration details are stored in the meter so that you can either make note or download them to a computer.

2. Start and Stop Measurements

To start a measurement, simply press the Run/Stop key

This starts the measurement and storing process for all parameters, the most important for noise at work being the Lavg and Peak. If the meter has Octave Band Filters fitted then these measurements start too.

When you are happy that you have measured for long enough (the average level has settled for example), simply press the Stop key.

Color Coded Display

The current state of the sound level meter can be seen at a glance. When not running the meter shows the current sound level and the border is red. When running the meter shows the measurement parameters such as Leq or Lavg and the border is green.


The CEL632C data logging Integrating Sound Level Meter is available as either Type 1 or Type 2 as defined by the international sound level meter standards.

Sound Level Meter Standards

  • ANSI S1.4 and ANSI S1.43 Type 1 or Type 2
  • IEC 60651 and IEC 60804 Type 1 or Type 2
  • IEC 61672 Class 1 or Class 2
  • ANSI S1.11-2004 (Octave Band and 1/3 Octave Band Filters)
  • IEC 61260 Class 0 (Octave Band and 1/3 Octave Band Filters)

Using a meter that meets these standards is essential for repeatable results and especially for any measurements that will be used for legal purposes.

Measurement range20 to 140 dB (single range), 143 dB Peak
Display320 x 240 pixel color TFT
Output to PCUSB Mini B
Batteries3 x AA Alkaline
(15 hours with backlight off)
External Power9 to 14V DC at 250mA
(2.1mm connector)
Dimensions72 x 229 x 31mm, 295g
2.8" x 9.0" x 1.2". 10.4oz
>2.5 years when logging set to 1 second
TimersDuration 1s to 24h
On/Off Timers: 6 sets with selectable times and repeat function.
Audio Recording8kHz sampling, 60 hours recording
24kHz sampling, 10 hours recording

Measured Parameters

Frequency weightingsA, C and Z (simultaneous)
Time weightingsFast, Slow and Impulse
Amplitude weightingsQ3, Q4 and Q5
Thresholds70 to 90 dB (applies to Lavg)
Sound LevelLXY, LXYMax, LXYMin, LC-LA
IntegratedLXeq, Lavg, LAE
Takt MaxLTM3, LTM5, LXIeq
Time History Level 1Periods of 1 minute to 1 hour
Time History Level 2Periods of 1 second to 30 mins
Octave Band ParamsLXY, LXYMax, LXeq
Octave Bands16Hz to 16kHz in 11 bands
1/3 Octave Bands12.5Hz to 20kHz

Where X is frequency weighting A, C or Z
and Y is time weighting Fast, Slow or Impulse