The hearing thresholds of 'normally' hearing young adults were measured
at various frequencies and used as the norm for 0 dB. Any loss is
therefore in dB HL (hearing loss) below this level. The range for
'normal' (not needing hearing aids) is often taken as +/- 20 dB, though
some people with 20 dB HL may prefer to use aids.
To find the actual dB SPL (sound pressure level) for normal hearing, may
I refer you to books such as 'An Introduction to the Psychology of
Hearing' by Brian Moore.
In article <6lqenv$skn$1 at news.nyu.edu>, Howard Sage <hs15 at is.nyu.edu>
>What is the hearing equivalent of 20/20 vision? That is, what decibel
>levels at what frequency are considered normal? Thanks in advance.
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