ST-12D Class 1 Integrating SLM
The IEC 61672-1 Noise Monitoring with 1/1 & 1/3 Octave Band Filters
Overview
ST-12D complies with the Class 1 IEC 61672-1:2013 standard, designed for occupational noise measurement and research. It features a wide measurement range of 25 to 140 dB and is capable of measuring parameters such as Leq, Lpeak, Lmax, Ln, and more. The ST-12D also supports a spectrum analyzer with optional 1/1 and 1/3 octave band filters, enabling real-time frequency analysis for precise noise assessments.
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2.4" Vivid Display
The full-color display allows for clear measurement readings with a user-friendly interface, intuitive charts, and graphs.
Microphone
ST-12D measures noise levels from a detachable 1/2 inch prepolarized condenser microphone with ±0.5 dB accuracy.
Output Interfaces
ST-12D includes USB-C, serial, and AC/DC ports, making it easy to connect and integrate with your system.
ScarletSound
The dedicated PC software for ST-12D user to view noise data, check audio recording and export log file for further report and analysis.
Class 1 Sound Level Meter
Designed for accurate noise measurements in various applications
High Precision
25 - 140 db wide range compliant with Class 1 IEC 61672-1:2013 standard
Full Capabilties
Integral & statistical calculations, dosimeter, and 1/1 & 1/3 octave band (optional)
Large Storage
Data logging and audio recording in MP3/WAV format with a 64 GB SD card
Parallel Analysis
Measures and displays the Leq value (A/C/Z frequency)
Key Features
Sound Analyzer
Class 1 Performance
Class 1 sound level meter with integral and statistical calculations, and a dosimeter function, ideal for beginners. Enhance your measurement needs with optional 1/1 and 1/3 octave band.
Data Visualization
Full-Color Screen
ST-12D makes it easy to read noise measurements through intuitive charts and graphs, enabling quick decision-making and analysis.
Data Management
Via PC Software
Scarlet developed ScarletSound PC software exclusively for the ST-12D. This software ensures intuitive management of historical records with charts and tables, as well as data exportation.
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Achieve precise noise measurement with ST-12D Class 1 sound level meter.
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Instant Printing
Traffic Noise Assessment
Tripod-Mounted
Construction Site
All-in-One Package
Audio Recording
ST-12D offers MP3/WAV audio recording formats with file export capability. Enhance recording efficiency with its trigger mode, activating recording only when sound levels reach a specified limit, effectively optimizing memory usage.
Optional 1/1 & 1/3 Octave Band Analysis
Experience precision in sound assestment with the optional 1/1 and 1/3 octave band analysis features for the ST-12D. These upgrades split noise into smaller frequency bands, helping you identify the noise source.
On-the-Go
Waterproof Case
Carry your ST-12D in our durable-design waterproof case, which protects the device and all its accessories, ensuring safe transportation wherever you go.
Frequently Asked Questions
Find quick answers below, or visit our FAQ page for more.
Is training required to use the ST-12D?
No formal training is needed. We provide complete instruction on how to use the device.
Can I extend the microphone away from the main unit?
Yes, microphone extension cables are available in 2.5m and 5m lengths.
Can I connect the ST-12D to external systems or weather stations?
Yes. ST-12D supports analog outputs and RS-232, enabling integration with external systems.
Add-Ons
Sound Calibrator
Calibrate your sound level meter periodically to ensure accurate measurements for critical assessments.
Instant Portable Printer
Print noise data on-site with our portable thermal printer, easily pair with your sound level meter.
Outdoor Kit
All-weather resistance with an anti-perching spike, the outdoor kit ensures obstacle prevention for reliable noise measurements.
Our Clients
Specifications
- Performance
- Design
- Operation
- Features
- Package List
- FAQ
- Download
| Item | Description |
|---|---|
| Fulfils standard | IEC 61672-1: 2013 Class 1 |
| Main parameters of measurement | LXYp, LXYmax, LXYmin, LXeq, LXeq,T, LXeq,t, LXpeak, LXE (SEL), E, LN (N=1~99): L5, L10, L50, L90, L95, SD, Ldn, Ld, Ln, TWA, LEX,8h, LAVG, DOSE; X = A, C, Z ; Y = F, S, I, I10 |
| Measurement range | 25 to 140 dB (143 dB C Peak) |
| Frequency range | 10 Hz ~ 20 kHz |
| Accuracy | ± 0.5 dB |
| Frequency weighting | A, C, Z |
| Time weighting | F, S, I, I10 |
| Integrating time | 1s to 99 h 59 m 59 s |
| Audio recording | Record noise data in MP3/WAV format; Synchronize/Trigger mode; Sampling rate: 12 kHz, 24 kHz, 48 kHz / 16 bit, 24 bit |
| Refresh rate | 0.5 s |
| Item | Description |
|---|---|
| Dimensions | 250 × 76 × 33 mm |
| Weight | 340 g |
| Display | 2.4-inch; 240 × 320 pixel full-color display; Adjustable brightness & backlight can be turned off |
| Display resolution | 0.1 dB |
| Output interface | USB type-C, Bluetooth, AC/DC signal, Serial |
| Item | Description |
|---|---|
| Power supply | 4 x AA alkaline batteries; External power supply (USB type-C adapter): 5V, 1A |
| Operation time | Max 24hrs by 4 x AA alkaline batteries (The operation time varies depending on the device settings and battery type) |
| Operation environment | Working temperature: -20 to 60 °C; Relative humidity: 20% to 90% |
| Storage capacity | 4 GB internal memory; 64 GB SD card |
| Features |
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| ▪ IEC 61672-1: 2013 Class 1 |
| ▪ Easy-to-use interface |
| ▪ 2.4" full-color display |
| ▪ Synchronous multi sound analyzers |
| ▪ Leq value with A/C/Z frequency weightings |
| Package List |
|---|
| ▪ ST-12D Class 1 sound level meter |
| ▪ Windscreen |
| ▪ USB-C to USB cable |
| ▪ USB power adapter |
| ▪ Serial to RS232 cable |
| ▪ Serial to USB cable |
| ▪ AA batteries |
| ▪ Calibration certificate |
| ▪ User guide |
| ▪ Waterproof carrying case |
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No formal training is needed. ST-12D features an intuitive interface, making it easy to use for professionals and beginners alike.
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An accurate noise measurement instrument that meets IEC 61672-1:2002 standards (or equivalent standards such as BS EN 61672-1:2003). It has tighter tolerances (+/- 1.9 dB at 1 kHz) compared to Class 2 (+/- 2.2 dB). Class 1 meters are ideal for measuring sound pressure, Leq, and peak sound pressure, often required by regulations like the UK’s Noise at Work.
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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.
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Using a windscreen or weatherproof outdoor kit helps reduce wind noise and ensures accurate readings in outdoor settings.
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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.
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Yes. ST-12D supports analog outputs and RS-232 serial communication, enabling integration with external systems such as weather stations or environmental monitoring system.
Software
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ScarletSound – Sound Data Management Software for ST-12D and ST-591 (Windows utility)2026.02.0979.78 MB
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ScarletSound – Sound Data Management Software for ST-12D and ST-591 (Windows utility)2025.07.1183.27 MB
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Datasheet
User Guide
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Fulfils Standard |
IEC 61672-1:2013 Class 1 | IEC 61672-1:2013 Class 1 | IEC 61260-1:2014 Class 1 |
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Accuracy |
±0.5 dB | ±0.7 dB | ±0.7 dB |
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Measurement Range |
27-140 dB | 25-140 dB | 20-142 dB |
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Display |
240×320 full-color display | 128×64 OLED | 240×320 color screen |
Where does Scarlet Sound Level Meter Apply
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