Article
The influence of different microphone positions on the frequency analysis of snoring sounds
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Published: | July 8, 2008 |
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Introduction: The frequency analysis of snoring sounds can serve as a diagnostic tool for the topodiagnosis of snoring sounds. Published data vary depending on the used microphones and their positions. Aim of the study was to analysis the frequency spectra of snoring sounds recorded at different positions and to propose a standardized positioning of the microphones.
Methods: Ten snoring episodes of 5 different patients were simultaneously recorded in supine position (30 cm/100 cm free hanging central, 30 cm lateral right and left side from the head, contact microphone (CM) cervical and parasternal). The microphones had a flat frequency response (40–18,000 Hz, 10–18,000 Hz). The digital recording was performed by 8-channel mixer. The analysis was conducted by comparison of the frequency bands and peak intensities.
Results: Parasternal and cervical positioning of the microphones revealed significantly deeper frequencies of the frequency bands above 300 Hz and 1000 Hz, respectively. There was no difference concerning the frequency bands of the positions 30 cm/100 cm central, right or left. The peak intensities were lower at parasternal and higher at 100 cm central position.
Conclusions: The presented data emphasize that the positioning of the microphones has influence on the recorded frequency of snoring sounds. The central free hanging position 30 cm away from the patient’s head can be recommended to obtain unaltered natural snoring sounds. The data of CM should be interpreted carefully for the frequency analysis of snoring sounds