FONIX® FP35 Touch - Frye Electronics

152 FONIX FP35 Hearing Aid Analyzer
Figure 5.5.4.3—Comparison of 3RD OCT analyzis (CRV1) with 100 Hz FFT analysis (CRV2).
Note: The bottom left corner of the graph indicates whether the measurements
are displayed in third octave analysis (3OCT) or 100 Hz FFT (FFT).
5.5.5 Important Notes on DSL Testing
The DSL fitting method is slightly more complicated than the other fitting rules
available on the FP35 analyzer. For this reason, it is important to keep a few
things in mind when using DSL:
• DSL was initially developed for children. For this reason, it is important
to input the client’s age when generating a target for a child. If no age for
the client is set, the analyzer will assume that it is generating a target for
an adult. See Section 5.3.4 for instructions on how to generate a target.
• The DSL WDRC target will change depending upon the source level of
CRV 2. So, if you would like to see the DSL WDRC target for 80 dB SPL,
for example, set the amplitude of CRV 2 to 80 dB SPL. The DSL LIN target
will also adjust to the amplitude of CRV 2, but its adjustments will be linear.
• DSL demands a slightly different speech weighting in its measurement
signals than the speech weighting we usually use. When fitting an adult,
DSL requires the adult long-term average speech spectrum (A-LTASS)
weighting. When fitting a child, DSL requires the child long-term average
speech spectrum (C-LTASS). The FP35 will automatically use these
speech weightings unless specifically directed otherwise. See Section
2.5.2.1 for more details.