![equal loudness and hl decibel scale equal loudness and hl decibel scale](https://cdn01.dailycaller.com/wp-content/uploads/2019/06/decibelchart.jpg)
And, any amplification prescription should be based on dB SPL, as hearing aid performance was measured, not dB HL as audiograms were recorded.
![equal loudness and hl decibel scale equal loudness and hl decibel scale](https://static.vecteezy.com/system/resources/previews/007/002/545/original/decibel-scale-sound-levels-free-vector.jpg)
To this end, the relationships between frequency, sound pressure, and loudness in normal ears were measured, with the goal being to restore these relationships in the impaired ear. The hearing aid should assist in helping the impaired ear to behave as if it were a normal ear. Otometry was founded on the premise that in order to find the best amplification for a hearing-impaired person, the prosthetic need should be based on normal ear performance.
![equal loudness and hl decibel scale equal loudness and hl decibel scale](https://www.ndrha.org/assets/4546-19985/decibel-scale-large.png)
A more detailed account can be found at: Otometry As such, this topic has a place in the historical development of the rehabilitative efforts involved in the discipline of hearing. Otometry is seldom, if ever, used currently, but the approach taken to establish its basic principles have been employed by essentially all current hearing aid fitting formulae, whether recognized or not. 1–5 Victoreen was a self-taught physicist, engineer, inventor, and at the time, the owner of the Vicon Instrument Company, manufacturing hearing aids in Colorado Springs, CO. It was presented as being based on science rather than on historical practice, supposition, and trial and error, as were the fitting approached used at that time.ĭeveloped by John Victoreen, LLD, otometry was presented as a scientific prescription to hearing aid fitting. In the late 1950s, a fitting approach called otometry was introduced.