Products > Sound Level Meters > CEL633C Environmental Noise Meter with 1/3 Octaves

CEL633C Environmental Sound Level Meter with 1/3 Octaves

CEL633C Sound Level Meter
CEL633C Sound Level Meter

Price List

Type 1 Environmental Sound Level Meter with 1/3 Octaves
In stock

Type 1 Kit with Meter, Calibrator and Case
In stock
Type 2 Environmental Sound Level Meter with 1/3 Octaves
In stock

Type 2 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 USA: $40.00

Delivery Service: Five working days*

* 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.

Type 1 Environmental Sound Level Meter with 1/3 Octaves
In stock

Type 1 Kit with Meter, Calibrator and Case
In stock


  • Data Logging with Time History Noise Profile stores
  • Real-Time 1/3 Octave Band Filters
  • Voice Notes and Audio Recording
  • Automatic Timers
  • Measures Leq, Lavg, Min, Max, Ln, etc. Simultaneously
  • Range: 20 to 140 dB(A)
  • Data Markers and Back Erase


  • Environmental Noise Surveys
  • Occupational Noise Measurement


The CEL633C Sound Level Meter is for measuring environmental noise in communities and around the perimeter of industrial sites. Fitted with Octave and 1/3 Octave Band Filters, this meter is also suitable for tonal noise analysis.

The CEL633C is the top-of-the-range sound level meter and available as either Type 1 or Type 2 - the most common for environmental noise measurement being the more accurate being Type 1. This meter also has everything needed for occupational noise measurement in line with the OSHA, MSHA, ACGIH and EU regulations, making it ideal for anybody involved in both environmental (outside the factory) and occupational (inside the factory) noise.

If the meter is to be left unattended in poor weather conditions then the Outdoor Kit should be used to offer protection against the elements. The Outdoor Kit also includes a rechargeable battery pack for longer term monitoring.


  • ANSI S1.4 and ANSI S1.43 to Type 1 or Type 2
  • IEC 61672 Class 1 or Class 2
  • IEC60851 and IEC 60804 Type 1 or Type 2
  • ANSI S1.11-2004 and IEC 61260 Class 0 (Octave and 1/3 Octave Band Filters)

Octave Band Filters

The meter is fitted with real-time Octave Band Filter, which are sometimes needed for noise sources that may be tonal or for assessing hearing protector performance. As well as measuring the Leq and Lmax in each band, the CEL633C meter also measures the statistical parameters, Ln, in each of the Octave bands.

Average Sound Level and Statistical Parameters

The CEL633 has a very wide span, covering 20 to 140dB in a single range. This is particularly important when monitoring in an environment with generally low noise levels and occasionally high ones - for example when cars pass. The most useful parameter when measuring environmental and community noise is the Leq, the average sound level. The meter measures the periodic Leq and also includes five Ln values for statistical analysis of the noise.

Data Logging and Software

The CEL633C 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 CEL633C is a Sound Level Meter that includes the usual environmental noise measurement parameters along with real-time 1/3 octave band filters for tonal noise assessments. It also has a detailed Time History store and automatic measurement timers.

  • Environmental noise measurements
  • Noise Ordinance and Community noise assessments
  • Noise in mixed residential and industrial areas
  • Occupational noise measurements
  • Noise source identification

Due to the nature of environmental noise surveys (both the acoustic nature and the political nature) we recommend the use of a Type 1 sound level meter.

This version of the CEL630 series of meters includes all the Environmental noise parameters along with a detailed time history store and automatic timers, making it ideal for both short term and longer term assessments.

As most occupational noise regulations accept Type 2 as being adequate, all versions of the CEL633 are suitable. If you need to measure both environmental and occupational noise then this meter will do both.

Short Term Environmental and Community Noise Surveys

The CEL633C sound level meter measures the noise parameters that are needed by most regulations:

  • Periodic A-weighted Leq (the average sound level)
  • Ln Percentiles (the statistical values such as L10 and L90)
  • 1/3 Octave Bands for tonal noise 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 car, a strong gust of wind blowing the leaves or somebody shouting. The CEL633C can record the audio so that you can listen to the interesting bits, enabling you to make a positive identification of the noise source.

Long Term Environmental Noise Surveys

The addition of a detailed time history store allows for post processing and graphing the noise levels down to a resolution of 1 second, and the automatic timers make it easy to run repeating measurements (for example repeating 5 minute measurements in addition to the 1 second Time History).

The sound level meter can by mounted on a standard camera tripod, but if it is to be left unattended in poor weather conditions you will also need the weather protection offered by the Outdoor Kit.

Occupational Noise

The CEL633C is also suitable for the measurement of noise in the workplace:

  • Lavg and Leq (average sound level) for TWA calculations
  • Peak for loud banging noise
  • "A" and "C" weighting for hearing protector evaluation
  • Octave band measurement for detailed hearing protector evaluation

Environmental Noise

The CEL633C is an Environmental sound level meter, suitable for applications that demand an accurate meter of the correct grade along with detailed measurement storage with Time History and automatic measurement timers.

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 environmental noise measurements
  • Meets the required standards (Type 1 or Type 2)
  • All parameters needed: LAeq, LAmax, Ln, etc.
  • Storing and download to computer
  • Detailed time history store
  • Color coded display for ease of use

As this meter measures all parameters at the same time there is no need to select what you need beforehand. Just make the measurement and everything is there.

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 as shown on the right 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.

Manual Measurements

To start a measurement, simply press the Run/Stop key, shown on the right.

This starts the measurement and storing process for all parameters, the most important being LAeq, Lmax and Ln (L10, L90, etc). It also stores the time history of the noise, which provides a graph of the sound level over time.

When you are happy that you have measured for long enough 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 and the border is green.

Automatic, Repeating Measurements

For many environmental noise surveys, you need periodic (usually 5 minute, 15 minute or 1 hour) measurements showing values such as the Leq and the L90.

To make this type of measurement, set the meter to make repeating measurements of the required duration. The meter will now run for the specified period. It will then stop, store the results and start again automatically. Advanced timers even allow different measurement times for different days.

It is better to mount the meter on a tripod for this type of measurement. A tripod mount is included on the back of the meter. It can be fitted to a standard camera tripod, or we can provide you with a suitable one.

Measurement Stores

The CEL633C comes complete with a number of noise measurement stores:

  • Time History - usually set to a fast rate, such as 1 second, to provide a detailed graph of the sound level over time
  • Periodic Measurements - usually set to 5 minutes, 15 minutes or 1 hour depending on applications. Can also be fixed periods. These are the most important environmental noise measurements, including parameters such as LAeq, LAmax and LA90.
  • Audio Recordings - recordings of the actual sound so you listen and make a positive identification of the noise source.

All these measurement stores are included with the CEL633C sound level meter, even if you choose not to buy the additional software. There is more information below about the different download options.

The more advanced Insight software can be downloaded free of charge for 30 days in case you are not sure whether you need the extra reporting features that it offers.

CasellaDrive Free Software

When the CEL633C is connected to a computer it works like a memory stick, so there are no complicated driver installations. However, the files are coded and compressed so you won't be able to read them directly.

The CasellaDrive software decodes the files and makes them available to copy into Excel or any similar spreadsheet program.

Most files are simple Comma Separated Text (CSV) files that can be read into many different programs. Audio recordings are in the standard WAV format, to be listened to using standard media playing applications.

Insight Software

The Insight software is an option that can be purchased with the meter or at a later date. A trial version can also be downloaded - this is a full featured version of the software but time limited to 30-days, after which time you need to buy a license to continue using it.

This software downloads the measurements from the sound level meter, storing them on your computer. You can carry out analysis of the sound levels and produce a number of reports.


The CEL633C data logging Integrating Sound Level Meter is available as either Type 1 (CEL633C1) or Type 2 (CEL633C2) as defined by the international sound level meter standards.

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
Statistical5 x Ln values
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

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 Filters)
  • IEC 61260 Class 0 (Octave 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
>1 year 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