Technical Column

Non-Invasive Acoustic Testing for Sealed Devices — Inspecting Internal Sounds from Outside with AEB × HBK Sensors —

2025年8月16日

Simplified Performance Testing Using Anechoic Box + Sound Level Meter

Introduction: How Do You Measure Sounds You Can’t Reach?

Many modern devices—from smart speakers to sealed sensors—generate internal sounds that must be evaluated for quality assurance.
However, opening the enclosure or placing sensors inside is often not possible due to:

  • Waterproofing or dustproofing requirements
  • High-voltage or sensitive internal circuitry
  • Production constraints in mass testing environments

The solution: acoustic inspection from the outside, using a controlled environment and precision measurement tools.

System Overview: AEB × HBK for External Acoustic Sensing

ComponentDescription
Measurement EnvironmentAEB (Anechoic Box): Blocks environmental noise and reflections
SensorsHBK Free-Field Microphones + LAN-XI front-end
Target ProductsSealed enclosures, potted modules, water-resistant electronics
Analysis SoftwareHBK PULSE / BK Connect for FFT, comparison, and anomaly detection

This setup allows for stable, repeatable measurements of internal acoustic behavior, without opening the device.

Applications and Use Cases

  • Detecting abnormal resonance or buzzing inside an enclosure
  • Identifying loose components or vibrating panels without physical access
  • Monitoring back-side cavity behavior in speaker modules
  • Checking for air leakage or mechanical misalignment via acoustic patterns
  • Comparing frequency signatures across multiple units for consistency

Key Advantages

Non-invasiveNo need to open, disassemble, or connect to internal points
ConsistentHigh repeatability thanks to AEB’s quiet, reflection-free space
QuantifiableRecordable FFT data, usable for production QC logging
FlexibleSuitable for development, incoming inspection, and aging tests

Ideal for

  • Bluetooth speakers, wireless modules, and IoT devices
  • Medical devices with sealed or sterilized casings
  • Manufacturers of acoustic or structural enclosures
  • Engineering teams analyzing changes caused by design modifications

Customization & Integration Support

  • Custom AEB sizing for your device portfolio
  • HBK microphone and range selection based on acoustic target
  • Threshold-based NG/OK logic with spectrum overlay comparison
  • Integration with automation (PLC, barcode scanning, etc.)

[Contact Moritani for System Integration Support]

お問い合わせ

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    Moritani Shokai
    (Machinery Department No. 2, Tokyo Head Office)

    +81-3-3278-6127

    • Download

      Download

      You can download our brochure (PDF) from here.

    • Faq

      Faq

      Here you can find answers to common questions about the HBK × Sonora solutions.

    Introduction of the Manufacturer

    • ホッティンガーブリュエルケアー Hottinger Bruel & Kjaer

      HHBK is a merger of two companies: Brüel & Kjær of Denmark and HBM of Germany.
      Brüel & Kjær is one of the world’s leading manufacturers of acoustic and vibration measurement instruments, known as a total measurement chain supplier.

      Learn more about HBK

    • ソノーラテクノロジー Sonora Technology Co., Ltd.

      Sonora Technology is a leading Japanese manufacturer of industrial anechoic chambers and anechoic boxes.
      From design and manufacturing to installation and acoustic performance assurance, Sonora provides fully integrated solutions to build complete acoustic measurement environments from the ground up.

      Learn more about Sonora

    Contact / Request Brochure

    For inquiries or consultations regarding the total solutions provided by HBK × Sonora, please feel free to contact us using the Contact button.
    If you would like a brochure sent by mail, please use the Request Brochure button.