Product Manual

3-4
100 Hz to 600 Hz
Leak Noise
Listening Range
100 Hz to 800 Hz
100 Hz to 1200 Hz
200 Hz to 600 Hz
200 Hz to 800 Hz
200 Hz to 1200 Hz
400 Hz to 600 Hz
400 Hz to 800 Hz
400 Hz to 1200 Hz
100 200
LOW
400
600 800
HIGH
1200
location (on the street, at the meters, etc.) is louder. Often the meter can distin-
guish which location is louder when the user’s hearing can not tell.
High and Low Frequency Filters
Figure 3-1 shows the three (3) low frequency filter switches and the three (3) high
frequency filter switches. The three (3) low frequency filters are set at 100 Hz,
200 Hz and 400 Hz. If the 100 Hz filter switch is depressed, then all noises and
sounds at 100 Hz frequency and lower are filtered out. If the 200 Hz filter or 400
Hz filter switches are selected, then all noises and sounds at these frequencies
and lower are filtered out. The three (3) high frequency filters are set at 600 Hz,
800 Hz and 1200 Hz. If the 1200 Hz filter switch is depressed, then all noises and
sounds at 1200 Hz frequency and higher are filtered out. If the 800 Hz filter or
600 Hz filter switches are selected, then all noises and sounds at these frequencies
and higher are filtered out.
Usually the 100 Hz low frequency filter and the 1200 Hz high frequency filter are
selected initially until specific extraneous noises, such as traffic, wind, etc., are
identified audibly by the user. The six (6) low and high frequency filters combine
to allow 9 different listening ranges as shown below in Figure 3-3.
Figure 3-3 Listening Ranges for Combinations of Filters
The low frequency filter and the high frequency filter can often be used to elimi-
nate many extraneous noises such as traffic and wind.