The core of using sound intensity measuring instruments correctly lies in "standardizing operating procedures, controlling environmental interference, and accurately calibrating equipment" to ensure the reliability of measurement data. The following are specific steps and precautions:

1、 Before measurement: equipment inspection and environmental preparation

This step is the foundation of accurate data, and it is necessary to eliminate equipment failures and environmental interference.

Equipment calibration: Ensure that the instrument has "zero error"

Calibration must be performed before each measurement. Specific steps:

Connect the sound intensity probe to the host and preheat for 10-15 minutes (to stabilize the electronic components).

Using a standard sound source (such as a piston sounder, typically at a frequency of 1000Hz), align the probe with the sound source at a distance of 5-10cm according to the calibrator instructions.

Enter the "calibration mode" of the instrument, wait for the reading to stabilize, and confirm that the displayed value is consistent with the standard sound source pressure level (allowable error ± 0.5dB). If the deviation exceeds the range, recalibration or maintenance is required.

Attention: It is recommended to calibrate every 3 months, and if frequently used, calibrate monthly to avoid errors caused by probe aging.

Environmental investigation: reduce external interference

Sound intensity measurement is easily affected by background noise and reflected sound, and needs to be processed in advance:

Choose a windless or low wind speed environment (wind speeds greater than 2m/s will produce airflow noise and require windproof covers).

Stay away from unrelated sound sources (such as air conditioning, traffic, and conversation), and the background noise should be at least 10dB lower than the measured sound source (background noise can be measured first, if not met, the measurement location needs to be changed or sound insulation measures need to be taken).

Avoid measuring in highly reflective environments (such as open rooms or metal walls), as reflected sound can cause the sound intensity value to be artificially high. To reduce reflection, add sound-absorbing materials (such as sponges).

2、 Measurement: Operating standards and parameter settings

Adjust parameters according to the measurement purpose to ensure that the probe position and angle are correct.

Probe placement: Aim at the sound source to avoid obstruction

The sound intensity probe (usually a dual microphone array) needs to be facing the sound source, with the axis aligned with the radiation direction of the sound source (deviation ≤ 10 °, otherwise it will result in lower sound intensity values).

Measure the distance according to the standard (such as ISO9614):

Near field measurement (<1m): Suitable for low sound sources (such as speakers), avoid probe contact with the surface of the sound source.

Far field measurement (>3m): Suitable for large equipment (such as fans), it is necessary to ensure that the sound source is in the "far field area" of the probe (distance ≥ 3 times the size of the sound source).

When holding the probe, the arm should be stable to avoid the body blocking the probe (the human body will reflect sound waves), and it is best to use a tripod to fix it.

3、 After measurement: data recording and equipment maintenance

Ensure data integrity and extend device lifespan.

Data recording: Detailed annotation of measurement conditions

In addition to the sound intensity value (in dB), the recorded content should also include:

Measure time, location, and ambient temperature (temperature affects air sound velocity and indirectly affects sound intensity calculation).

The working status of the sound source (such as equipment load: no load/full load, speed, etc.).

Abnormal situations (such as sudden noise, probe movement) facilitate later data correction.

Equipment storage: prevent probe damage

After the measurement is completed, turn off the host, disconnect the probe connection, and cover the probe with a special dust cover (to prevent dust from entering the microphone).

The probe needs to be stored separately in a shock resistant box (to avoid squeezing the spacing between the two microphones, as spacing errors can cause errors in sound intensity calculation), and the host should avoid humid and high-temperature environments (storage temperature 0~40 ℃, humidity ≤ 70%).

Summary: Key Principles

The accuracy of sound intensity measurement relies on the three in one control of "calibration environment operation": calibration ensures instrument accuracy, environment eliminates interference sources, and operation standards ensure the "correct dialogue" between the probe and the sound source. Following the above steps can effectively avoid errors caused by improper operation (such as ± 3dB deviation due to lack of calibration and ± 5dB deviation due to angle errors), allowing the measurement data to truly reflect the sound intensity characteristics of the sound source.