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Real Ear Sound Pressure Levels Developed by Three Portable Stereo System Earphones
American Journal of Audiology
|December 15, 2015
Summary
Portable stereo system (PSS) earphones, including supraaural, semiaural, and insert types, produce different real ear sound pressure levels (SPLs). Differences in low-frequency output significantly impact overall sound output, meaning equivalent inputs do not guarantee equivalent SPLs across earphone styles.
Area of Science:
- Audiology
- Acoustics
- Consumer Electronics
Background:
- Portable stereo system (PSS) earphones are widely used for personal audio.
- Variations in earphone design may lead to differences in sound reproduction.
- Understanding these differences is crucial for accurate audio perception and hearing health.
Purpose of the Study:
- To investigate and compare real ear sound pressure levels (SPLs) across three distinct types of PSS earphones.
- To analyze frequency response, high-frequency average (HFA) output, peak output, peak output frequency, and overall RMS output for each earphone type.
Main Methods:
- Utilized a probe tube microphone system (Fonix 6500 Hearing Aid Test System) for measurements.
- Tested three PSS earphone models: supraaural (Sony Model MDR-44), semiaural (Sony Model MDR-A15L), and insert (Sony Model MDR-E225).
- Recruited twelve adult male subjects for the study.
Main Results:
- Significant differences were found in the mean overall Root Mean Square (RMS) outputs among the PSS earphones.
- No significant differences were observed in mean HFA output, peak output, or peak output frequency.
- Observed variations in low-frequency response significantly contributed to the differences in overall RMS output.
Conclusions:
- Different styles of PSS earphones do not produce equivalent real ear SPLs even with identical input signals.
- Low-frequency response variations are a key factor in the differing overall sound pressure levels.
- Users and manufacturers should be aware that earphone type influences actual sound delivered to the ear.
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