Dr. Jonathan Vaisberg and colleagues at Western University’s Nation Center for Audiology recently published results of an independent study investigating the impact of audible bandwidth on perceived sound quality in hearing impaired listeners. The paper concluded that participants experienced a higher quality, preferable listening experience when listening to the full bandwidth of the Earlens System. The full paper is available for review on the Otology & Neurotology Journal homepage, or can be directly downloaded from this link: Vaisberg et al. (2020).
The study is summarized as:
Objective: To determine sound quality for extended bandwidth amplification using a direct drive hearing device.
Study Design: Prospective double-blind within-subjects repeated measures study.
Setting: University hearing research laboratories.
Patients: Fifteen experienced hearing aid users with symmetric mild-sloping-to-severe sensorineural hearing loss.
Intervention(s): Sound quality ratings of speech and music passages were obtained using the Multiple Stimulus with Hidden References and Anchors (MUSHRA) protocol after wearing a direct drive hearing aid for at least 4 weeks. Passages were processed to filter out low-frequency (below 123 and 313 Hz) and high-frequency (above 4455, 5583, 6987, and 10,869 Hz) energy.
Main Outcome Measure(s): Comparison of sound quality ratings for speech and music between low and high-pass filter frequencies measured from 0 to 100, where 0 represents “bad” and 100 represents “excellent.”
Results: Wider bandwidth stimuli received higher sound quality ratings compared with narrower bandwidth stimuli. Conditions with more low-frequency energy (full-band and 123 Hz cut-off) were rated as having higher sound quality. More low-frequency energy in the 123 Hz condition was rated as having higher sound versus the 313 Hz condition (mean difference: 11.2%, p = 0.001). Full-band conditions with more low- and high-frequency energy were higher than the other high-frequency cutoff conditions (mean difference range: 12.9–15%, p < 0.001).
Conclusions: The direct drive system provides higher sound quality of both speech and music compared to narrowband conditions. Sound quality improvements were mainly attributable to low-frequency sound, but stimuli with specific high-frequency content were rated with higher sound quality when additional high-frequency energy was present.
Read the full article here: 2020 Vaisberg et al Sound_Quality- Otology & Neurotology