Bone Conduction Headphone Acoustic Testing with VibroMicro
1. Technology Background
Bone conduction is a sound transmission method that converts audio signals into mechanical vibrations, transmitting sound waves through the human skull, bony labyrinth, inner ear lymph fluid, spiral organ, and auditory nerve to the hearing center. Compared with air conduction, bone conduction eliminates many sound transmission stages, enabling clear sound reproduction in noisy environments.
With advantages including hearing safety and noise immunity, bone conduction technology has long been used in medical, military, scientific research, and professional sports fields. As technology advances and living standards improve, bone conduction headphones, glasses, helmets and other products are increasingly favored by consumers.
2. Testing Challenges & Traditional Methods
2.1 Traditional Testing Limitations:
Sound pressure transmission through air, collected by microphones
Multiple sound-electricity signal conversions with significant signal loss
Measurement systems typically require artificial ears and analyzers
Indirect measurement cannot accurately reflect actual vibration performance
2.2 Industry Requirements:
Direct vibration source measurement
High-precision vibration parameter acquisition
Frequency response characteristic validation
Production line compatibility
3. Dynatronic Solution Design
3.1 Testing Principle
Coherent laser interferometry for direct vibration source measurement
Complete vibration parameter acquisition: phase, amplitude, velocity, acceleration, frequency
Professional waveform analysis tools
3.2 Test Configuration
Test Device: Brand X Bluetooth bone conduction headphones
Mounting Method: Headphone fixed via bracket on one side
Audio Source: Huawei Mate 20 smartphone via Bluetooth
Signal Generator: Frequency Sound Generator APP
Volume Range: 0-MAX
Frequency Range: 20-20,000 Hz
Testing Equipment: Dynatronic VibroMicro VM-S-100 Laser Doppler Vibrometer
Analysis Software: Dynatronic VibroSoft
4. Testing Methodology
4.1 Test Setup
Secure headphone transducer unit in fixed position
Align laser beam perpendicular to vibration surface
Establish Bluetooth connection with signal generator app
Configure sweep frequency parameters (20Hz-20kHz)
4.2 Data Acquisition
Execute frequency sweep while recording vibration data
Capture complete vibration waveform characteristics
Analyze frequency response and harmonic distortion
Measure vibration amplitude at different frequency points
5. Results Analysis
5.1 Performance Validation
Bluetooth transmission functionality: Normal operation
Frequency response range: 20-20,000 Hz achieved
Sensor capability: Meets frequency response testing requirements
Vibration frequency measurement: High stability, minimal error
5.2 Key Findings
Mounting method may affect amplitude measurements and cause resonance
Direct vibration measurement provides accurate performance characterization
Non-contact method eliminates loading effects on lightweight transducers
6. Technical Advantages
6.1 Measurement Performance
High Sensitivity: Nanometer-level displacement resolution
Non-contact Operation: No interference with device under test
Direct Signal Acquisition: Optical measurement of vibration source
Comprehensive Parameters: Phase, amplitude, velocity, acceleration, frequency
6.2 Practical Benefits
Compact Size: Minimal space requirements for integration
Flexible Installation: Adaptable working distances
Production Suitability: Ideal for inline measurement systems
High Accuracy: Minimal measurement error for reliable results
7. Implementation Value
7.1 Quality Assurance
Objective evaluation of acoustic performance
Quantitative vibration parameter measurement
Consistent testing standards across production
7.2 Development Support
Rapid prototype validation
Design optimization guidance
Performance benchmarking
7.3 Production Benefits
100% inline testing capability
Reduced manual inspection requirements
Comprehensive data traceability
8. Conclusion
The Dynatronic VibroMicro VM-S-100 based testing solution provides an advanced method for bone conduction headphone acoustic performance evaluation. By directly measuring vibration characteristics through non-contact laser interferometry, it overcomes limitations of traditional acoustic testing methods. The system delivers high-precision, reliable measurements suitable for both R&D validation and production line integration, supporting the growing bone conduction audio device market with robust quality assurance capabilities.
