wardzal9 at mailw.starnetinc.com (Thomas Wardzala) wrote:
>As for equipment.......Virtual puts out an audiometer that goes into the
>high-Hz's. Koss also puts out a system. All the earphones are
>circumaural, so that adds another problem in calibration....What coupler
>do we use (?).....
I am familiar with two high frequency audiometers.
The Beltone 2000 has output to 20 Khz. The unit also allows for use
of intermediate frequencies at all hz so you can get a threshold at
odd places. For example, I discovered my upper limit at 90 dB is
17,250 Hz. If high frequency is important to you, make sure your
dealer also purchases the coupler from Beltone to do this high freq
calibration. Beltone has developed their own standards for this
calibration. This unit uses Sennheiser <SP?> headphones with a
special DIN jack rather than typical 1/4 inch connector, so it does
take a little extra time to install this in your typical sound room.
In addition, Monitor Instruments makes a portable high frequency
audiometer. This unit starts at 8KHz and goes up. It is small enough
to be taken to bedside and can therefore be very practical for those
who wish to detect early onset of ototoxicity.
In addition, I have heard that there is some research that some
newborns have upper limits to 22Khz, but I don't remember the journal