I stumbled upon this study from that goes into the problem of people with hearing aids not understanding conversations.
The authors show that hearing aids are only made to work in a narrow band of the lowest frequencies based on century old telephone studies. They then go on to show that, in fact, we need to hear higher frequencies from 8Khz to as much as 9 and 15Khz to understand words. It a deep read into why our aids really don’t work right. But it seems that if we were to work on tweaking the settings of our aids to amplify its highest ranges we could improve our understanding significantly.
I am surprised that no one is talking about these findings. they are definitely significant.
Abstract
While human vocalizations generate acoustical energy at frequencies up to (and beyond) 20 kHz, the energy at frequencies above about 5 kHz has traditionally been neglected in speech perception research. The intent of this paper is to review (1) the historical reasons for this research trend and (2) the work that continues to elucidate the perceptual significance of high-frequency energy (HFE) in speech and singing. The historical and physical factors reveal that, while HFE was believed to be unnecessary and/or impractical for applications of interest, it was never shown to be perceptually insignificant. Rather, the main causes for focus on low-frequency energy appear to be because the low-frequency portion of the speech spectrum was seen to be sufficient (from a perceptual standpoint), or the difficulty of HFE research was too great to be justifiable (from a technological standpoint). The advancement of technology continues to overcome concerns stemming from the latter reason. Likewise, advances in our understanding of the perceptual effects of HFE now cast doubt on the first cause. Emerging evidence indicates that HFE plays a more significant role than previously believed, and should thus be considered in speech and voice perception research, especially in research involving children and the hearing impaired.##