Background: Expanding the accessibility of voice assessments across all sorts of conditions and environments is essential for improving patient outcomes, particularly in noisy settings like hospitals and workplaces. Voice disorders significantly impact communication and quality of life, yet traditional air microphone-based assessments often fail in these acoustically challenging environments. Contact microphones, which capture vibrations directly from the vocal source, present a promising alternative by minimizing background noise interference. This study aims to characterize commercially available contact microphones to identify reliable options for use in noisy environments.
Methods: Six commercially available contact microphones were evaluated using an electromechanical shaker driven by a signal generator. Each microphone was sequentially mounted to the shaker's test point using double-sided adhesive tape, and a logarithmic frequency sweep from 20 Hz to 20 kHz was applied at constant amplitude. The output signals were recorded at 48 kHz/24-bit and analyzed using FFT power spectrum analysis to determine frequency response characteristics, sensitivity, resonant frequencies, and roll-off points. All measurements were tested three times to ensure measurement repeatability.
Results: Normalized frequency analysis revealed distinct response patterns among contact microphones, with some devices expected to outperform traditional air microphones by maintaining higher SNRs and offering better noise resistance. Variations in sensitivity and response are anticipated to highlight each device’s strengths and weaknesses. Calibration with accelerometers has verified the accuracy of vibration measurements, supporting this as an ongoing project with promising preliminary results in achieving clearer and more accurate frequency responses.
Conclusion: This ongoing study will provide essential baseline data supporting the use of contact microphones in noisy environments, such as hospitals and occupational settings. Findings are expected to guide the selection of affordable, easy-to-use contact microphones for reliable voice assessments, ultimately enhancing diagnostic accuracy and utility in challenging acoustic conditions.