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Sound level meter and spectrum analyser

Integrating Sound level meter class 1 with audio recording expandable to spectrum analyzer for third octave bands

  • INCLUDED Audio recording with pre-recording and voice comments
  • Increased storage with MicroSD memory card
  • Automated Parameters: timers, DEN thresholds, external input:
    1) Auto start/stop of measurement and logging
    2) Auto audio recording & pre-recording
  • Erasing backward (BACK ERASE function)
  • Built-in USB & BLUETOOTH® connectivity
  • Sensitivity, date & time change history
  • Ready for environmental monitoring:
    1) Auto ON and automatic measurement and logging start
    2) Downloads while measures
  • Free or diffuse sound-field correction options
  • Can be expanded with advanced measurement modes (see optional Modules)

Main Features


The ON&PLAY philosophy has been developed to be intuitive - getting first time users up & running quickly & providing a stress-free return to measurements, even after long periods of inactivity.

offers a simple and enjoyable experience from the first moment of contact with the device.

With ON&PLAY, measurement has never been so easy.

Removable MicroSD memory card

The information measured by the SC420 (final results and time histories), audio files and voice notes are saved on the MicroSD card inserted into the SC420.

Once the measurements are complete and the SC420 is powered-off, the MicroSD card can be removed and inserted into a computer. The data can then be transferred using the program 'Memory Download' - the download can be completed much faster this way.

MicroSD cards up to 32 GB have been tested successfully.  

Modular Platform

The SC420 is an instrument that stands out for its power, versatility & ergonomics. It delivers high performance as a Class 1 integrating sound level meter (in accordance with IEC 61672, ANSI S1.4 and ANSI S1.43).

Thanks to its modular platform, the SC420 can be expanded with advanced measurement options such as 1/3-octave band spectrum analysis, FFT analysis and reverberation time measurement.

Automated Parameters

The SC420 has a complete system of automated parameters, such as starting & stopping measurement and audio recording. Automatic timers and triggers are also available when exceeding threshold by DEN time-zones .

Its power and versatility offer infinite combinations which will provide optimal performance for even the most demanding of users.  

Ready for environmental monitoring

The SC420 is designed to work as an automatic continuous noise monitoring unit. An environmental monitoring powering option is available, which allows measurements to be resumed after recovery from a power failure. 

Optimal file structuring allows efficient data transfer & manipulation; this includes downloading while measuring and erasing parts that have already been downloaded.    

Audio recording and voice comments

The SC420 can record audio files (listening quality), whilst it logs acoustic functions, facilitating its subjective evaluation and the recognition of sound sources.

USB and Bluetooth® connections

The SC420 communicates with a PC through a USB port and through Class 1 wireless Bluetooth® communication, in order to download & manipulate data, as well as allowing external control and real time visualization.


Back erase

With the Back erase function, the SC420 can delete the last 10 seconds of the measurement in progress. This option is ideal when unwanted noise events occur during measurement.

Optional Modules


What does it measure?

Occupational noise mode simultaneously measures all the parameters necessary to evaluate the noise exposure of the worker with and without hearing protectors (SNR, HML and Octaves). 


  • Industrial acoustic
  • Noise measurements for air conditioning installations (HVAC)
  • Sound Insulation measurements
  • Frequency analysis of industrial noise, environmental and labour
  • Background noise in rooms


What does it measure?

16 Hz to 16 kHz octave band filters analysis plus overall functions and NC and NR curves


  • Sound insulation measurements
  • Noise measurement for air conditioning installations ( HVAC)
  • Frequency analysis of industrial noise, environmental and labour
  • Background noise in rooms


What does it measure?

10 Hz to 20 kHz 1/3-octave band filters analysis plus overall functions


  • Sound Insulation measurements in  third octave band
  • Assessment of environmental noise (Corrections for the presence of tonal and impulsive components and low frequency content) 
  • Detection and identification of noise sources


What does it measure?

Reverberation time measurement by 1/1 and 1/3-octave bands using the interrupted noise and the integrated impulse response methods. Includes parameters for the evaluation of non-linear decay curves and the influence of the filters


  • Evaluation of the reverberation time of rooms 
  • Measurement of sound absorption in a reverberation room 
  • Measurement of soud insulation in buildings and of construction materials


What does it measure?

FFT Analysis of 10000 lines from 0 to 20000 Hz (2 Hz/line)


  • Detection and evaluation of the tonal components
  • Frequency analysis of continuous and transient signals (industrial and environmental) 
  • Evaluation of tonal components according to ISO 1996-2 and DIN 45681.


What does it measure?

Records WAV (uncompressed) format audio files, 24 bits resolution, 48 kHz sampling frequency and constant gain for later analysis


  • This mode can be advantageous independently of the application in which it is being used as it allows a perfect acquisition of the audio signal, to carry out a post processing and obtain additional information.

Standards and certificates

Table of standards

ANSI / ASA S1.4:2014
Integrating sound level meter class 1
DIN 45657:2014
regarding the Taktmaximalpegel function
IEC 61010-1:2010
A1:2019 II polution degree
EN 61010-1:2010
A1:2016 II polution degree
UNE-EN 61010-1:2011
+A1:2020 II polution degree
IEC 61672-1:2013
Class 1 sound level meter
OIML R 58:1998
Class 1 Sound level meter
OIML R 88:1998
Class 1 Integrating sound level
OIML R 130:2001
Class 1 Filters
ANSI S1.4-1983(R2006)
Part 1 Type 1 Sound level meter
ANSI S1.43-1997(R2007)
Class 1 Integrating sound level
ANSI S1.11-2004(R2009)
Class 1 filters
EN 61260-1:2014
Class 1 filters
EN 61672-1:2013
Class 1 sound level meter
Complies with 2014/30/UE and EMC 2014/35/UE regulations

Type-approval Certificates

11/09/2013: Type examination
25/07/2013: Software
07/10/2013: Additional 1 Type examination
27/09/2013: Additional 1 Software
11/11/2013: Additional 2 Software
30/05/2014: Additional 3 Software
07/11/2014: Additional 4 Software
22/05/2015: Additional 5 Software
18/12/2015: Additional 6 Software
22/12/2017: Additional 7 Software
26/03/2019: Additional 2 Type examination
11/07/2022: Type examination

17/02/2014: Type-approval Certificate

App for mobile devices

CESVA SC420 Link

Available on Google Play for free. SC420 Link is a mobile application designed for Android. Thanks to its intuitive operation, the user can take measurements with the SC420 sound level meter from the touch screen of a smartphone and configure its measurement parameters remotely.

The connection of the SC420 Link application with the SC420 is done through Bluetooth and allows full control of the sound level meter: Change of measurement mode, start and stop of measurement, pause, backerase and start of audio recording.

SC420 Link allows to display in real time the graphic and numerical information of the measurement modules of the SC420: Sound level meter, Spectrum analyser 1/1*, Spectrum analyser 1/3* and Noise at work*.

*Optional modules

Simply mount the SC420 sound level meter on a tripod at the measurement point, position yourself at a suitable distance, connect it to your smartphone via Bluetooth and start measuring remotely safe from potentially dangerous environments and without interfering with measurement in sensitive environments.

Install CESVA SC420 Link

More information



The  SC420 sound level meter measures a lot of functions for very long periods of time and also records audio files automatically. The best way to approach the analysis of all these functions together with the qualitative information provided by the audio files is to use the CESVA Lab software application. 

Download data

CESVA Lab is cost free and gives you a simple way to download all the information from the SC420. 

View and Listen

Moreover, it provides an intuitive and user-friendly interface which allows numerically and graphically display of all the measurement information on the screen in several synchronized panels (spectrum and time history graphs and 3D spectrograms) and listen to the audio files for each sound event.  

Export and Resport

CESVA Lab allows you to copy any table or graph from the screen to the clipboard to be able to paste it into any text editor. In addition, simply by pressing a button, you create a PDF report with all the information of the selected instant, personalized with your own annotations. It also allows you to work with spreadsheets. CESVA Lab always exports with the same format, this allows you to create your own spreadsheets templates and reports.

Edit and re-calculate

If what you want is to recalculate a section, simply select it, add it to a layer and simply calculate. Different layers, containing several sections, can be calculated simultaneously. Each layer is calculated and saved in a separate file.  

Result Merging Tools

The Result Merging Tools (SE003) brings together the final results of multiple measurements in a single file (. csv). It is a practical and simple software that, together with the CESVA sound level meters, becomes the perfect solution for all types of measurement campaigns.

How does Result Merging Tools work?

Groups the final results of several measurements in a single csv file. Select the folder where the measurements you want to group are located, select the measurements, the functions and the frequency weighting that you want to appear in the resulting csv file. Click the button to create the csv final file. This will appear automatically in the same folder where we had the initial measurements. The csv final file will contain the final results of the measurements we had selected. The Result Merging Tools (RMT) merges, in a single file (. csv), the final results of different measurements carried out with the SC250/SC202 or SC420 sound level meters. This software allows you to customize the resulting file to fit the user's needs. Result Merging Tools (RMT) is characterized by its simplicity of use and compatibility with most applications. In addition to saving work time, it eliminates errors made when grouping results manually. In a few seconds the user will obtain a file with the final results of all measurements.

Complete sets


Set consisting of: SC420 sound level meter, CB006 Sound level calibrator, TR40 tripod, ML043 transporting briefcase


Set consisting of: SC420 sound level meter, CB006 Sound level calibrator, ML013 transporting briefcase


Set consisting of: SC420 sound level meter, CB006 Sound level calibrator, TR040 tripod, ML063 transporting briefcase

Optional accessories


Class 1 acoustic calibrator


Tripod for sound level meter, dosimeter and microphone. Maximum height 1.1 meters.


Tripod for sound level meter, dosimeter and microphone. Maximum height 1.55 meters.


Mains power feeder with USB


Carrying case (48 x 37 x 16 cm) for sound level meter, acoustic calibrator and Tripod


Carrying case (39 x 32 x 12 cm) for sound level meter and acoustic calibrator


Carrying case special  weather (51 x 38 x 15 cm) for sound level meter, acoustic calibrator and Tripod


Outdoor kit


Extension cable 3m


Extension cable 10 m


Extension cable 30 m


Breakout cable


Output audio cable


Tripod support for the microphone


3 m extension rod for microphones. Adaptor for microphone supplied.


Converter for battery 12 V to 5 V (microUSB)


Bluetooth device for Wireless communications (for PC).




SC420, Sound Level Meter & Spectrum Analyser

SC420 Link, SC420 Sound Level Meter App

CESVA Lab Software: Downloading data

SC420 Sound Level Meter: Handling