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been entered in the demographic information. If the date of birth has not been
entered, toggle the age button to choose the appropriate age range. The
selections correspond to the BKB-SIN test norms.
Group
The Group menu item acts as a toggle to indicate the ‘group’ for the testing. In
the BKB-SIN test, up to 2 groups may be used to compare different conditions.
Such comparisons might be used to demonstrate the benefits of amplification
(unaided vs. aided) or assess directional microphone performance (no directional
mic vs. directional mic). The BKB-SIN Test is a flexible tool that may be
applied clinically in a variety of ways by adjusting the presentation level or the
presentation mode.
Research
The Research menu item is a check box to indicate that the system is in Research
mode. Research mode is designed for research and special applications. In the
Research mode the Output for Channel 1 and 2 may be controlled independently.
In the ‘Standard’ mode the Output for Channel 2 cannot be adjusted. The Split
Track lists should be used for Research mode. The standard BKB-SIN sentences
have the target talker and background babble recorded on the same channel and
the S/N ratio integrated into the recording. The Split Track lists provide the
ability to control the signal and noise in ways not available in the standard
sentences.
Split Track I
In these recordings the target talker and background babble are recorded on
separate channels (Channel 1 = target talker, Channel 2 = background babble) so
the speech and babble may be presented through separate loudspeakers in the
sound field. When the audiometer attenuators are set correctly (both attenuators
set to identical presentation levels) these tracks maintain the same signal-to-noise
ratios as on the standard recording; that is, the signal-to-noise ratio automatically
changes by 3 dB for each sentence.
Note:
When using Split Track I both Channel 1 and 2 outputs should be set to the
same HL level. If the output HL is different for the channels then the S/N ratio
will not be correctly maintained.
Split Track II
Both channels of these tracks (Channel 1 = target talker, Channel 2 = background
babble) were recorded at a constant overall level. The signal-to-noise ratios do
not change automatically after each sentence; the tester must manually adjust the
level of the target talker and/or the background babble to change the signal-to-
noise ratio.
