Medel SYMFIT 6.1, Руководство пользователя

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2 dB more of output, however, this causes strong
distortions if sounds reach the output limit of the
system. It is not recommended to use this setting.
Compression
Frequency dependent amplification for
loud and soft input sounds
It is possible to separately adjust the gain for loud (90
dB) and soft (40 dB) input sounds in up to 8 channels.
With the help of the eyeglass control these 8 channels
can be combined into 1, 2 or 4 groups and then be
adjusted accordingly. This is very useful as it allows the
clinician to directly respond to comments of the user
concerning specific listening situations.
As already mentioned in the section Basic Tuning
changes in the input related amplification are equivalent
to changes in the compression settings (compression
kneepoint and ratio) in the specific frequency band
which should therefore be observed (figure 28).
Setting the Compression Kneepoint and
Ratio
Of course Connexx also allows to manually set
Compression Kneepoints and Compression Ratios. The
frequency range can be also split here with the
eyeglass control.
By double-clicking on the respective field a dropdown
menu opens which allows to set the compression
kneepoint between 35 dB and 75 dB, the compression
ratio between 1.00 (no compression) and a maximum
of 4.00.
Dual and Syllabic compression
DUAL (double temporal component compression)
Dual compression operates with both a fast and a slow
level meter. The fast level meter provides an immediate
reduction in gain for higher-level impact sounds. The
fast attack time is 5 ms. The second level meter with
900 ms attack and 1400 ms release time provides gain
adjustments based upon the average level of the
incoming signal.
In this way, the Amadé operates with a quasi-automatic
gain control, while at the same time preserving speech
dynamics essential to understanding, without allowing
uncomfortably loud peak levels.
Dual compression follows the overall speech level and
limits distortion. For users who suffer from mild
recruitment (mild to moderate hearing loss), dual
compression protects the temporal contrast of their
own voice.
figure 28