13
IR Plus Assistive Listening System
System Settings
Most settings are adjusted via the web interface by using a computer (see "Web Control Interface" on page 15). A handful of
settings can be adjusted via the front panel display (see "Front Panel Interface" on page 22).
Any configuration to the IR+ system is done through the IR M1, which passes the configuration setting onto other IR+ devices.
Audio Settings
The Audio Settings provide the ability to change the audio characteristics for different listening applications.
Audio Input Source
The Audio Input Source menu has five possible selections to choose from: Line In, Mic In, 400Hz Test Tone, Mic + Phantom Power,
or Dante.
Selecting an Audio Source Appropriate for Hearing Impaired Listeners
The IR + transmits audio with excellent fidelity. Therefore, the audio source signal should be of the highest audio quality and not
subject to a compressor, limiter, reverberation, or other signal processing equipment. While compressed audio is available through
the IR +, excessive compression is not helpful to the hearing impaired and can contribute to excessive noise in the audio.
The IR + audio source signal is usually connected to a mixer’s line output signal which is behind the mixer’s parametric equalizers
but ahead of any equalization used for house loudspeakers.
If audio delay is available for use in large auditoriums, it’s usually best to use it. Because radio signals travel faster than sound,
delaying the transmitted audio so that an average listener (in the middle of the listening area) hears the transmitted audio a few
milliseconds after audio from the main sound reinforcement system speaker is helpful. This will also help audience members who
lip read.
Audio Input Gain
The Audio Input Gain adjusts the audio output level from the IR M1. Changes to the input level will affect the level indicated by the
front panel display when audio is present. The gain can be adjusted from -60dB to +24dB.
Audio Presets
The Audio Presets allow the user to quickly and easily configure the IR M1 for common applications. The audio preset can only be
adjusted via the Web Interface.
There are three pre-configured to choose from:
Hearing Assist, Music, and
Voice.
When one of these selections is made, the
performance of the IR M1 is immediately optimized for the needs of that application (an adjustment is automatically made to the
Low-pass Filter, High-pass Filter, and Compression).
By default, the IR M1 is shipped in the
Music
mode.
For music, concerts, and other applications where the highest audio quality is desirable,
Music
is the recommended mode of
operation.
For hearing assistance applications, or applications where the message is critical for listening,
Hearing Assist
is the
recommended mode of operation.
For speaking and other voice applications,
Voice
is the preferred mode of operation.
A
Custom
preset is also available for configuring channel-specific audio settings.
Audio Input Level Indicator
The bar graph indicator shows audio level in 3dB steps at the output of the audio level processing circuit. The indicator is peak
responding and is calibrated so that optimum level is reached when the VU meter only fully lit (+9dB) occasionally and typically
hovers around 2/3rds lit (0dB). Adjust the audio levels from the front panel (see "Audio Channel Menu" on page 23)or from the
web interface (see "Audio Page" on page 18).
Input Overload Indication
The OLED Display shows an exclamation mark (!) above each channel's VU meter as an overload warning each time the audio
signal exceeds the capacity of the input circuit. Either the source of the audio coming in to the IR M1 needs to be adjusted to
correct this or the Audio Input Gain needs to be adjusted. A warning will also appear on the web interface if overloaded.