ST-25D Class 2 Sound Analyzer

Occupational Noise Measurements

Overview

ST-25D is the Class 2 sound analyzer that complies with IEC and ANSI standards. Ideal solution for detailed sound analysis with accurate sound level measurements and identify noise source with single device. The ST-25D is the perfect solution for environmental noise measurement, featuring built-in data logging and a comprehensive statistical analyzer.

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Microphone

1/2" pre-polarized condenser microphone features a removable preamplifier and offers a sensitivity level of -40dB

Outputs & Indicators

DC/AC, USB, and RS232 outputs are included for seamless data transfer and integration, along with LED indicators for clear visual feedback.

2.6’ Full-Color Screen

The 240x320 resolution display features a main menu with four quick-access options: measurement, setup, recall, and calibration

Why Choose ST-25D?

IEC Certificate

Adhere to the highest standards for testing and conformity assessment

Recording

Record Sound Data and Save it into “WAVE” format

Management

Real time monitoring software(Windows)

28-133 dB

Wide measurement range

Key Features

Overview

Noise Measurement

ST-25D Class 2 sound level meter with 1/1 octave band noise analysis

ST-25D measures noise level with A, C, and Z frequency weightings, and F, S, and I time weightings. It supports multi-index analysis and advanced 1/1 Octave Band analysis.

Flexible Operation

Reliable Noise Data

ST-25D mounted-tripod for noise assessment

Offers flexible usage options for quick measurements, whether used handheld or mounted on a tripod. It measures from 28 to 133 dB, ensuring compliance with Class 2 standards.

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Measure environmental noise levels with the ST-25D sound level meter

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Reliable Statistical Analysis

ST-25D provides detailed insights with up to 28 statistical Ln% values, including L1, L5, L10, L50, L90, and L95 for comprehensive sound level assessments.

Outdoor Kit

Built to be waterproof and featuring an anti-perching spike to prevent obstacles, this kit ensures smooth and accurate noise measurement operations.

Frequently Asked Questions

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

Which class of sound level meter do I need?

Depending on your application, Class 1 is preferred for high-accuracy or legal use; Class 2 works for general needs.

Can the ST-25D record audio?

Audio recording is optional; when enabled, it saves sound data in WAV format for analysis.

Does the ST-25D have GPS functionality?

GPS analyzer can be included when placing your order.

Specifications

Datasheet
Features
Package List
FAQ
Download

ST-25D Class 2 Sound Level Meter Package List

User Guide Datasheet

Item	Description
Fulfils standard	IEC 61672 Class 2
Main parameters of measurement	LFp, LSp, LIp, Leq1, Lpeak, Leq,T, LFmax, LFmin, LSmax, LSmin, LImax, LImin, SEL,Ts, Tm, Volt, E.
Measurement range	28 dB - 133 dB (141 dB Peak)
Measurement level	"Z(FLAT): 38 to 130 dB C peak: 145 dB Z(FLAT): peak: 145 dB"
Frequency range	20 Hz to 12.5kHz ± 1 dB (not including microphone)
Optional upgrade	1/1 octave band, GPS, FFT, dosimeter function
Power supply	4×AA batteries or external power supply
Environment	Working temperature: -10 to 50°C; Storing temperature: -20 to 70°C

Features
▪ 28 dB - 133 dB Wide Measurement Range
▪ IEC 61252:2002 & IEC 61672
• ±1dB High Accuracy & 0.1dB Resolution
▪ Leq Value with A/C/Z/B Frequency Weightings

Package List
• ST-25D Class 2 sound level meter
• 1⁄2” prepolarized condenser microphone (pre-installed)
• Windscreen
• RS-232 cable
• 5V power adapter
• Mini USB cable
• AA batteries
• User manual
• Calibration certificate
• Waterproof carry case

No formal training is needed. ST-25D 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.
Audio recording is an optional feature for the ST-25D. When equipped, it can record sound data and save it in WAV format, facilitating further analysis and documentation.
No, the GPS analyzer must be requested when placing your order. This feature enables the device to record both noise sources and measurement data. Check out this video to learn how to view the GPS information.