>>I have driven hearing aid receivers well beyond 15k Hz with standard
>>op amps and signal generators. This is useless as far as most
>>conventional hearing aids go due to feedback, amplifier limits and the
>>limited high frequency requirements of the user > 4k Hz. I would
>>guess that the aid that is advertised in the birding magazine uses
>>walkman type headphones along with conventional amps, mics and
>>batteries rather than hearing aid components.
>>>Not necessarily true. With the proper selection of microphone and
>receiver and the proper design of the acoustic system and electronics,
>extended response hearing aids are not only possible but do exist. The
>HiFi Kamp can easily have a response out to 16k and the majority of
>the aids that I design go out past 10k. However, you must be careful
>at how they are measured. If you go by just the standard ANSI 2cc data
>you won't see it. They are measured using good real ear systems, or
>simulated using Kemar.
I have designed a few extended response systems but we have found that
very few people benefit from them. Those who do have been < 30 years
old. It does little good to provide extended response when a person
is down 90 dB at 4kHz. Many of the older folk are confused by too
My original comment was about the listening aid in the birding
magazine. It would be far less expensive to design a listening aid
that used conventional mics, headphones and electronics than it would
be to use hearing aid specific components.
Have you found that a number of people benefit from extended response
systems? What types of losses have you seen that have responed to
this type of system?