
Noise is an omnipresent phenomenon in our modern world. Whether in industry, transportation, or leisure, controlling and measuring sound levels plays a crucial role in ensuring health, safety, and environmental concerns. Modern sound level meters enable precise measurements and help comply with legal noise limits. But how exactly do these devices work? In this article, we take a detailed look at the technology behind sound level meters, their applications, and the economic benefits of their use.
Fundamentals of Sound Measurement
Sound is measured in decibels (dB) and describes the sound pressure level that affects the human ear. Decibel values are logarithmic, meaning that an increase of 10 dB is perceived as a doubling of loudness. Sound level meters detect these pressure fluctuations and convert them into electrical signals, which are then analyzed and displayed. Components of a Sound Level Meter A modern sound level meter consists of several key components:- Microphone: The heart of the device, usually an electret condenser microphone, capturing sound signals.
- Preamplifier: Amplifies the microphone signal before further processing.
- Frequency Filter: Determines which frequency ranges are considered (A-, C-, Z-weighting).
- Analog-to-Digital Converter (ADC): Converts analog sound signals into digital values.
- Signal Processor: Calculates average values, maximum values, and stores data for analysis.
- Display & Storage: Shows the results and stores them for later evaluations.
Measurement Methods and Applications
Weighting Filters: A-, C-, and Z-Weighting To mimic the influence of the human ear, sound level meters use different frequency weightings:- A-Weighting (dBA): Takes human hearing into account and is used for environmental and workplace noise.
- C-Weighting (dBC): Captures low-frequency noise and is relevant for industrial applications.
- Z-Weighting (dBZ): Measures the entire frequency range without filtering.
- Fast (125 ms response time): Useful for rapid level fluctuations.
- Slow (1 second response time): Used for stable noises.
- Impulse Weighting: Measures sudden noise peaks.
- Class 1: Highest precision with a tolerance of ±1 dB.
- Class 2: More affordable variant with a tolerance of ±2 dB.
Feature | Class 1 | Class 2 |
Accuracy | ±1 dB | ±2 dB |
Application Area | Research, Laboratories, Industry | General noise measurement, Construction sites |
Cost | High | Medium to low |
Frequency Range | 10 Hz - 20 kHz | 20 Hz - 8 kHz |
Typical Use | Precision measurements | Standard measurements |
Technological Advances
Digital vs. Analog Sound Level Meters Modern digital sound level meters offer significant advantages over older, analog devices:- Automatic Data Logging: Measurements can be stored and analyzed later.
- Connected Devices: Data transmission via WiFi or Bluetooth to smartphones or computers.
- Real-Time Analysis: Detection of patterns and noise sources in real time.
- Energy Efficiency: Lower power consumption due to optimized electronics.
- Automatic detection of noise sources through algorithms.
- Adjustment of measurement strategies to the environment.
- Long-term trend analysis for noise reduction.
- Reducing workplace noise exposure lowers health costs.
- Automated measurements save working time.
- Avoiding fines by precisely complying with legal limits.
- Effective noise protection measures reduce long-term noise remediation costs.
Saving Potential | Traditional Method | Modern Sound Level Meters |
Working Time (Measurements) | 10 hrs/week manual measurement | 3 hrs/week through automation |
Health Costs Due to Noise Exposure | High due to insufficient protection | Reduced through precise control |
Fines for Noise Exceedance | Risk of high fines | Prevention through real-time monitoring |
Investment Costs | Low | Higher, but long-term savings |
Noise measurement resolution | 0,1 dB |
Noise measuring range | from 30 dB to 130 dB |
Measurement of sound pressure level (SPL) | Auto 30/130 |
Measurement of sound pressure level (SPL) | Hi 80/130 |
Measurement of sound pressure level (SPL) | Med 50/100 |
Internal memory for data saving | 32.700 recordings |
Backlit LCD display | 4 digit |
Bargraph | |
Device category (Class) | IEC61672-1 Class 2 |
Mini-USB interface for PC connection | |
Auto Power OFF | |
-10°C / 60°C - <75%RH | |
Power supply | 1x9V alkaline battery type IEC 6F22 |
Size (L x W x H) | 260x65x50 mm |
Weight | 280 gr |
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The C.A 833 Calibrator is a standard source (1kHz) used for calibrating sound level meters.
- Compliant with the IEC 942 type 2 standard
- Calibration level: 94 and 114 dB
- Usable microphone diameter: 2.5 cm / 1.3 cm / 0.64 cm
- Measurement of the equivalent continuous sound level (Leq)
- Recording of up to 64,000 measurement points
- Wide backlit screen with digital display and bargraph
- Microphone for remote use (extension accessory)
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- Dynamic range: 37 to 130 dB
- Accuracy: ± 1.5 dB
- Resolution: 0.1 dB
- Time weighting: Fast, Slow
- Frequency weighting: dB(A) et dB(C)
- Storage of maximum value
- Analogue output: 10 mV/dB and 1 VRMS - 600 Ohms
- Tripod insert
- Shockproof protective sheath
- Dimensions: 237 x 60.5 x 38 mm
- Weight: 230 g
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- Precise noise level measurements according to IEC 61672-1 Class 2 and ANSI S1.4 Type 2
- Ideal for health and safety inspections and immission control
- Integrated memory for up to 31 000 readings: long-term measuring possible
- PC software for data analysis and USB cable for data transfer
The testo 816-1 sound level meter is the professional model in the Testo sound level meter series. It is designed specifically for measuring noise levels in the workplace, in public places and in industry and production. Includes data storage and analysis.
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- Frequency evaluation according to characteristic curves A and C
- Easy to adjust (adjustment screwdriver included in the scope of delivery)
- Min./max. memory
- Integrated tripod knuckle screw (1/4 inch)
Determine the noise level quickly, easily and reliably in your day-to-day work: with the testo 815 sound level meter.
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