O-Solution DS-5000 Acoustic Power Level Measurement System

UPDATE 2026

Acoustic power level is the total amount of acoustic energy radiated into the air by a sound source per unit time. While general sound pressure levels are affected by the distance from the noise source and the measurement environment, acoustic power level is uniquely determined in relation to the noise source. Therefore, acoustic power level is effective for setting noise specifications and evaluation standards for equipment, and for evaluating noise reduction effects, and is a global indicator used in environmental labels and noise regulations in various countries.

Methods for measuring acoustic power levels are defined by ISO standards and JIS standards. Measurement principles include the sound pressure method using a microphone and the SI method using an acoustic intensity probe.

The diagram below shows the procedure for measuring acoustic power levels using the sound pressure method in a semi-anechoic chamber. Prepare a test environment and microphone placement that conforms to the standard, and acquire the sound pressure level at each measurement point (ambient noise, target sound source, and reference sound source if environmental correction is required).
Afterward, the sound power level is calculated by adding the correction terms specified in the standard.

It allows for easy measurement according to standards and output of reports in Excel format.
The standard settings can be customized, which is useful for calculations based on individual standards.

Generally, sound power levels are calculated within the range of 100 Hz to 10 kHz as defined by standards, but it is possible to extend this frequency range to include both low and high frequencies for analysis.
If there are many measurement points, it is possible to perform measurements in multiple separate steps. ^*1​

After calculating the sound power level according to the standard, detailed analysis can be performed using the recorded data.
Post-analysis allows for the calculation of FFT and instantaneous acoustic power levels, efficiently identifying frequency peaks, timings, and sound source locations that contribute to increased acoustic power levels.
This allows for cause analysis without the need for remeasurement, leading to cost reductions in noise testing.

*1 This service is available only if the sound source is reproducible and stable.
*2 While ambient noise correction and area correction are performed according to the standard, the calculations are performed using a different frequency or temporal resolution than the standard, so these are reference values and not compliant with the standard.
*3 To calculate the acoustic power level using the frequency resolution of the FFT, the OS-0522 FFT analysis function is required separately.

The standard for acoustic power level measurement is defined to allow measurement in various environments without limiting the object being measured. The OS-0541 conforms to the standard for acoustic power level measurement using the sound pressure method with a microphone. The OS-0524 octave analysis function is required separately.

ISO 3744:2025, Acoustics ─ Determination of sound power levels of noise sources using sound pressure ─ Engineering methods for an essentially free field over a reflecting plane

For measuring sound power levels, several international standards have been established depending on the required accuracy (grade) and measurement environment. Among these, ISO 3744 is the most widely cited standard for practical methods (grade 2), and typical methods include measuring at 10 points on a hemisphere.
ISO 3744 was revised in December 2025, the first revision in 15 years.

This revision streamlines complex regulations and simplifies the main text of the standard. Changes have also been made to environmental adjustments and the criteria for determining background noise. Please refer to the table below for the main changes.
The DS-5000 Sound Power Level Measurement System has been quick to adapt to this latest revision.
We provide highly accurate measurements that always comply with the latest standards.

Main revisions to ISO 3744

This is a typical configuration of a measurement system with 10 points arranged on a hemisphere.

* A separate computer is required. Recommended specifications follow those of O-Solution.
* A microphone stand or similar device is required to secure the microphone. Please contact us for details.
* A separate system operation verification fee will be charged if microphone stands or other equipment are selected or procured.

To perform acoustic power level measurements in accordance with standards, it is necessary to confirm that the test environment and measurement methods are suitable for the customer's test specimen. Leveraging the technology cultivated through contract measurement and noise reduction consulting, we provide services that allow our customers to measure with confidence. Please contact us for details on our follow-up services.

The construction of anechoic chambers and the fabrication of microphone domes can be provided by Japan Acoustic Engineering Co., Ltd., a company with a top-class track record in Japan. The company possesses high technical capabilities in a wide range of fields, from designing and constructing acoustic spaces to meet diverse needs, to noise reduction measures and support for the development of acoustic materials.

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By measuring according to standards, you can more accurately understand the overall sound of the product.

Machinery such as air conditioning equipment, home appliances (washing machines, vacuum cleaners, etc.), multifunction printers, automotive parts (motors), and generators.

By checking the sound power level and sound pressure level distribution simultaneously, it is possible to efficiently identify the source of the sound and verify the effectiveness of countermeasures.

Equipment with built-in motors tends to generate high-frequency noises that increase with rotational speed. Since high-frequency noises can sometimes be unpleasant, efforts to reduce them are important. The OS-0541 allows for post-analysis of measurement data to calculate the acoustic power level for tracking analysis. By understanding the overall acoustic power level in relation to rotational speed, it becomes possible to identify operating conditions that require countermeasures. The OS-0523 tracking analysis function is required separately.