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FM +
Ratio. If the audio preset is changed from Custom to Music, Hearing Assist, or Voice, the Custom settings are still saved for use in
the future.
High-pass Filter
A High-pass Filter cuts o low frequencies and lets high frequencies pass through. The pole frequency chosen is the point where
the cuto takes eect. The high-pass filter will help to remove low frequency noise from the transmitted audio signal, such as room
noise, a line hum, or breath accents picked up from an improperly installed microphone. Available frequencies are: 31, 63, 80, 100,
125, 160, 200, 250, 315, 400, 500, and 630 Hz.
Low-pass Filter
A Low-pass Filter cuts o high frequencies and lets low frequencies pass through. The pole frequency chosen is the point where
the cuto takes eect. The low-pass filter will help to remove high frequency noise from the transmitted audio signal, such as
hiss in the audio line as a result of room noise, sharp speech sounds, or other uncomfortable high frequency sounds. Available
frequencies are: 3.5, 4.0, 5.0, 6.3, 8.0, 10.0, 12.5, and 16 kHz.
Compression
Compression reduces the volume of loud sounds and boosts the quiet sounds to louder listening levels. It also limits loud sounds
to a lower level, protecting sensitive hearing. Compression is typically used for voice and hearing assistance applications for a
listener who has diculty hearing the quiet sounds of an audio broadcast.
For listening to music programs, concerts, etc., lower compression ratios or no compression is generally used. The FM + has three
selectable modes of compression: 1:1 (compression o), 1.5:1 (low compression) or 2:1 (high compression).
For applications such as music and voice, where high audio quality is desirable, 1:1 is the recommended mode of operation. For
hearing assistance or applications where the transmitted message is critical for listening, 1.5:1 or 2:1 is recommended.
NOTE: The FM + is shipped from the factory at a 1:1 compression ratio (no compression).
NOTE: Some hearing impaired people cannot tolerate as loud of a sound as those with normal hearing. Using compression
can help protect those users. However, compression also can make audio sound flat. Only use compression when it is the
best choice for the listeners.
Headphone Volume
The headphone volume level can be increased or decreased by using the Headphone Volume setting in the menu.
FM Output Power
The selectable transmitter power levels are Full, Medium (-10dB), Low (-20 dB), and O. By default the FM + is set to full power
mode. For general listening applications, full power is the preferred mode of operation. Full power provides an operating range of
up to 1000 ft (dependent on the environment and antenna installation).
For special listening applications, it may be desirable to reduce the overall operating range if:
• The audio transmission is to be contained to a smaller listening area;
• The signal is too strong and it is overloading the receiver
• Multiple transmitters are used in adjacent classrooms where the FM signals overlap each other.
In these cases, the power level can be reduced to -10 dB or -20 dB. The output may be temporarily set to o to help troubleshoot
interfering or overlapping Radio Frequency signals.
Time-Out
The Time-Out setting determines how long the transmitter continues to transmit over FM with no audio present (30 minutes, 4
hours, or Always On). After the time-out period occurs (with no audio input and no front panel button presses), the FM + will go
into sleep mode to conserve power. During sleep mode the transmitter is completely shut o and the power switch light will fade
from bright to dark to indicate the unit is in sleep mode.
Note: Time-out delay and Screen Time-out delay are two independent events.
Screen Lock
The front panel screen of the device can be locked to prevent any changes from being made outside of the web interface. This
option can only be toggled from the website.
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