ST-21D Class 2 Sound Level Meter

Integrating Algorithms for Occupational Noise

Overview

ST-21D Sound Level Meter meets the Class 2 IEC 61672:2013 standard, making it ideal for general environmental noise measurements. It calculates continuous sound levels and exposure over a set period, ensuring compliance with OSHA and Noise at Work regulations to protect employee hearing and safety.
ST-21D Class 2 Sound Level Meter
  • 1
  • 2
  • 3
Outputs & Indicators

Outputs & Indicators

It includes DC/AC, USB, and RS232 outputs for effortless data transfer and integration, with LED indicators providing clear visual feedback.

Display

Display

ST-21D comes with a clear, user-friendly OLED display, providing intuitive navigation and easy access to sound measurements.

Microphone

Microphone

The 1/2" prepolarized condenser microphone measures sound levels.

Why Choose ST-21D?

Designed for environmental & occupational noise measurements
High precision

High Precision

IEC 61672:2013 Class 2 standard with high accuracy of ±0.7 dB
Parallel Analysis

Smart Integration

Measures and displays Leq value with adjustable A/C/Z frequency weightings
Built-In Datalogger

Built-in
Datalogger

Download raw data directly to your computer using a USB cable

Interested in This Solution? Get a Quote Now!

Measure environmental noise accurately with the ST-21D sound level meter
Get a Quote

Data Transfer to Windows PC

Transfers data to a Windows PC via USB cable and stores up to 8,000 sets of measurement results, including timestamp, % dose, and TWA.

Get A Quote
Data Transfer to Windows PC

Quality Assurance & Packaging

Every ST-21D is rigorously tested for quality before shipping and securely packed in a cardboard hand carry case to protect its components. This ensures your sound level meter arrives in perfect condition, ready for use.

Quality Assurance & Packaging

Frequently Asked Questions

Find quick answers below, or visit our FAQ page for more.

Is training required to use the ST-21D?

No formal training is needed. We provide complete instruction on how to use the device.
ST-21D sound level meter

How often should I calibrate the ST-21D?

Conduct field calibrations before and after each use.
Construction worker

How is background wind noise reduced?

Using a windscreen helps reduce wind noise and ensures accurate readings in outdoor settings.
ST-21D tested before shipping

Our Clients

Specifications

  • Datasheet
  • Features
  • Package List
  • FAQ
  • Download
ST-21D Class 2 Sound Level Meter Package List
Item Description
Fulfils standard IEC 61672:2013 Class 2
Main parameters of measurement LFp, LSp, LIp, Leq,t, Lpeak, Leq,T, LFmax, LFmin, LSmax, LSmin, LImax, LImin, SEL, Lex8h, LAVG, TWA, DOSE, Ln1, Ln2, Ln3, Ln4, Ln5, SD,Ts, Tm, Volt, E
Measurement range 28 to 133 dB
Measurement level Z(FLAT): 38 to 130 dB / C peak: 145 dB / Z(FLAT) peak: 145 dB
Frequency range 20 Hz to 12.5 kHz
Display 128 × 64 OLED
Weight 0.4 kg
Application Sound level meter, noise dosimeter, data logging & precision recording (Optional)
Power Supply 4×AAA batteries or external power supply
Dimensions 310 × 72 × 32 mm
Features
▪ IEC 61672:2013 Class 2
▪ 28dB to 133dB wide measurement range
▪ Data Logging
▪ RS232 & USB Data Output
▪ Leq value with A/C/Z/B frequency weightings
Package List
▪ ST-21D sound level meter
▪ 1/2" prepolarized condenser microphone
▪ Windscreen
▪ User manual
▪ Calibration certificate
▪ Cardboard hand carry case
  • No formal training is needed. ST-21D features an intuitive interface, making it easy to use for professionals and beginners alike.

  • A Class 2 sound level meter meets the accuracy and performance standards defined by IEC 61672 for general-purpose sound measurements.

  • Your choice depends on the application:

    Class 1: Preferred for environmental noise surveys, low noise levels, legal applications, and standards like ISO 20906:2009 for aircraft sound monitoring.
    Class 2: Suitable for less demanding applications without strict accuracy requirements.

  • Conduct field calibrations before and after each use. Additionally, have the device professionally calibrated annually to maintain compliance with standards.

  • Using a windscreen or weatherproof outdoor kit helps reduce wind noise and ensures accurate readings in outdoor settings.

  • Yes, Scarlet offers microphone extension cables (available in 2.5m and 5m lengths) that allow the microphone to be positioned away from the meter, ideal for specific monitoring setups.

Learn More
Datasheet
  • ST-21D Class 2 Sound Level Meter – Product Introduction & Datasheet
    2022.02.25
    0.36 MB
User Guide
  • ST-21D Class 2 Sound Level Meter - User Guide
    2025.06.24
    0.99 MB

Get a Quote Today!

Thank you for the interest in ST-21D. Please fill out the form below. We will get back to you in few hours.

Contact Form
Contact Us