As the core tool for noise measurement, the performance indicators of a multifunctional sound level meter directly determine the measurement accuracy and adaptability to application scenarios. Analyze its key performance indicators from five dimensions:
1、 Core measurement range and dynamic performance
Sound level range
Modern multifunctional sound level meters typically cover a range of 20dB to 143dB (A-weighted), with some models expandable to 146dB (C-weighted peak), meeting the measurement needs of all scenarios from quiet environments in libraries to industrial stamping workshops. For example, the A-weighted measurement range of the AWA6228 sound level meter is 20dB to 143dB, and the C-weighted peak reaches 60dB to 146dB.
dynamic range
The dynamic range needs to exceed 100dB (A-weighted) to ensure that there is no need to frequently switch ranges in environments with alternating strong and weak noise, such as airport runways and terminals. Some models achieve a 105dB linear dynamic range through a 24 bit A/D converter, reducing range switching errors.
2、 Frequency and time weighting accuracy
Frequency weighting
It is necessary to support three weighting modes A, C, and Z simultaneously:
A-weighting: simulating the response of the human ear to 40 square pure tones, suitable for environmental noise assessment;
C weighting: Simulate 100 cubic meter pure tone response for high-intensity noise measurement (such as rocket launch);
Z-weighting: Linear response, used for spectral analysis.
For example, a certain model of sound level meter has a frequency range of 10Hz to 20kHz, with an error of ± 1dB, covering the infrasound to ultrasonic frequency bands.
Time weighting
Parallel support is required for three modes: F (fast), S (slow), and I (pulse):
F mode: Time constant of 125ms, suitable for fluctuating scenarios such as traffic noise;
S mode: time constant of 1 second, used for steady-state noise measurement;
Level I: Rise time of 35ms, capturing pulse noise such as punch presses and explosions.
Some models also support Peak mode with a rise time of less than 20ms, accurately capturing transient noise such as sound.
3、 Data collection and processing capability
Sampling rate and resolution
The model adopts a 48kHz sampling rate and 24 bit A/D conversion to ensure accurate restoration of high-frequency noise (such as ultrasonic cleaning machines). For example, a certain model achieves a resolution of 0.1dB through a 32kHz sampling rate, meeting laboratory level accuracy requirements.
Statistics and Spectrum Analysis
It is necessary to support the calculation of indicators such as statistical sound level (such as L90, L50, L10), equivalent continuous sound level (Leq), and noise exposure level (DOSE), and can optionally be equipped with 1/1 octave or 1/3 octave analysis modules to achieve noise source spectrum localization. For example, the octave band analysis software package of the AWA6228 sound level meter can cover the frequency range of 16Hz to 16kHz, which complies with the IEC612601 level standard.
4、 Environmental adaptability and reliability
Temperature and humidity range
The working temperature should cover -10 ℃ to 50 ℃, humidity 20% to 90%, and adapt to harsh environments such as outdoor monitoring and industrial workshops. Some models are designed with an IP65 protection level, which is dustproof and waterproof, ensuring stable operation in rainy or high humidity scenarios.
anti-interference capability
Using digital signal processing technology (DSP) and true RMS detection to eliminate harmonic distortion (total distortion ≤ 2.5%). For example, a certain model of sound level meter has a harmonic distortion of ≤ 1% at a frequency of 1000Hz, ensuring data reliability in complex electromagnetic environments.
5、 Storage and expansion functions
data storage
Built in large capacity storage (such as 16GB), can record over 9999 sets of measurement data, and supports SD card expansion to 64GB. Some models use GPS modules to achieve data geotagging, making it easy to draw noise maps.
Interface and Output
Requires RS-232, USB, Bluetooth and other interfaces to support real-time data transmission to computers or printers. For example, the AWA6228 sound level meter can be connected to a micro printer through an RS-232 interface to output measurement reports on site.