Sound Level Monitor Class 1
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Overview
Features
IEC 61672-1 Class 1 performance (factory-verified)
A/Z frequency weighting, Fast/Slow time weighting
1 dB-step errors ≤±0.3 dB across full range
Total linearity ≤±0.8 dB over 25–130 dB
Self-noise <19 dB(A)
Stainless steel IP-rated outdoor housing
How it works
The SB4651 features a precision measurement chain designed in accordance with IEC 61672-1 and GB/T 3785-1, delivering Class 1 performance that has been factory-verified. The sensor integrates with the Pro2 base unit via Modbus, providing continuous real-time noise data alongside dust, gas, vibration, and weather measurements.
Factory verification results include 1 dB-step errors of ≤±0.3 dB, total linearity of ≤±0.8 dB across the 25–130 dB measurement range, and self-noise below 19 dB(A). Calibration is performed using a standard 94 dB, 1 kHz acoustic calibrator with a recommended annual calibration interval.
Class 1 vs Class 2 Noise Monitoring
The existing Sensorbee Sound Level Meter (SB4652) provides Class 2 equivalent performance suitable for general environmental noise screening and indicative monitoring. The Class 1 SB4651 delivers tighter measurement tolerances required for:
- Regulatory compliance — BS 5228, BS 4142, and planning condition noise limits often require Class 1 instrumentation
- Legal evidence — noise data used in enforcement proceedings or legal disputes requires the highest measurement accuracy
- Planning applications — environmental noise surveys supporting planning applications typically specify Class 1 measurement
- Section 61 consent — construction noise monitoring for regulatory consent typically requires Class 1 accuracy
Applications
- Construction noise monitoring — BS 5228 compliant noise measurement at site boundaries and sensitive receptors
- Planning condition compliance — demonstrating adherence to noise limits set in planning permissions
- Environmental noise surveys — BS 4142 industrial noise assessments and environmental impact studies
Noise nuisance investigation — regulatory-grade evidence for noise complaint investigation and enforcement - Airport and transport noise — long-term noise monitoring programmes around transport infrastructure
Technical Information
| Standard | IEC 61672-1 / GB/T 3785-1 Class 1 |
| Measurement Units | LAeq, LAmax, LAmin |
| Frequency Weighting | A and Z weighting |
| Time Weighting | Fast and Slow |
| 1 dB-step Errors | <=+/-0.3 dB |
| Total Linearity | <=+/-0.8 dB (25 to 130 dB) |
| Self-noise | <19 dB(A) |
| Calibration | 94 dB, 1 kHz acoustic calibrator |
| Calibration Interval | Once per year |
| Level Range | 25 to 130 dBA |
| Dynamic Range | >=110 dB |
| Frequency Range | 10 Hz to 20 kHz |
| Dimensions | D76 x 300 mm |
| Weight | 300 gram |
| Power Supply | DC 5V |
| Interface | Modbus RTU |
| Enclosure | Stainless Steel + Polyamide |
| Operating Temperature | -10 to +50 C |
| Operating Humidity | 0 to 90 %RH |
| Mounting | Flat area or pole mount |
| Standard | IEC 61672-1 / GB/T 3785-1 Class 1 |
| Measurement Units | LAeq, LAmax, LAmin |
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The Sensorbee Air Pro 2 is a professional-grade environmental monitoring station
