More sensitive than human hearing

• Detection and localization of air leakage noise
• Full sensitivity under production noise
• Classification and localization of the defect
• High reliability and reproducibility (no fatigue)
• Full sensitivity at high sound pressure level

The human ear is very sensitive for detecting impulsive distortion as generated by irregular defects, such as a rubbing coil, loose particles, buzzing parts, air leakage noise or wires bouncing on the diaphragm. 

Some defects in loudspeakers, such as loose particles in the gap, produce random symptoms which might not be audible after production but which become worse after some time and may be detected when the transducer is mounted in the car audio system or in any other final application. To avoid shipping a defective unit, defects should be detected in manufacturing even if they are inaudible. In addition to that, testing at high SPL level, ambient noise and fatigue reduces the sensitivity of a human tester.

KLIPPEL QC SYSTEM outperforms the human tester by using patent protected technologies, such as

• time domain analysis to detect impulsive distortion (loose particle)
• avoiding spectral masking of defects in the psycho-acoustical processing
• averaging deterministic symptoms of defects
• compensating regular distortion as found in good units
• demodulating air leakage noise
• separating distortion from production noise
• multi-channel processing and cross correlation technique
• beam steering for localizing the source
• using an expert system for defect classification.

Meta-Hearing-Technology allows the detection of loose particles which are masked by the regular distortion as found in any good units and which are not audible for a human tester or conventional measurement instruments.