Fallback Mode - L-Acoustics LA4X User Manual

When the LOCK status has been recovered, the user can manually reactivate channel pair AB applying the sequence
described in Figure 35:
4.9.2

FALLBACK MODE

An automatic fallback option can be enabled or disabled. When enabled, and when the AES/EBU input mode is
selected for input pair AB, the amplified controller will automatically switch from input pair AB to input pair CD in case
of digital signal failure on input pair AB (no clock, loss of lock, CRC error, bipolar encoding error, data slip). This option
prevents sound cut.
After the digital signal has returned to normal state, reverting to input pair AB is not automatic and must be done
manually by the user. This can be done simultaneously for all concerned amplified controllers from
LA NETWORK MANAGER software.
Precautions for using the automatic fallback option
Before enabling the automatic fallback option, some precautions have to be taken in order to avoid sound cut or
level differences in case of switch from input pair AB to input pair CD:
 Input pair CD must be connected to an audio source (analog or digital) playing the same program as the digital
audio source connected to input pair AB.
 When an analog audio source is connected to input pair CD, the level of the digital audio source connected to
input pair AB must be aligned to the level of the analog audio source using the AES/EBU GAIN control (see
section 4.9.3).
Two FALLBACK MODE settings are available, as described in the following table:
OFF
ON
To select the fallback mode follow these steps (see also Figure 36):
From the main menu select INPUT SETTINGS and press the OK key or the encoder wheel (or ESC to
1.
abort).
2. Turn the encoder wheel to select FALLBACK MODE.
3. Press the OK key or the encoder wheel to enter the page (or ESC to abort).
4. Turn the encoder wheel to select the chosen setting.
5. Press the OK key or the encoder wheel to validate the setting (or ESC to abort).
Invalid audio (validity bit)
A validity bit at non-audio value will not trigger the automatic fallback. Instead the signal will be muted.
LA4X_UM_EN_4.0
Figure 35: Reactivating channel pair AB
Table 8: FALLBACK MODE settings
Automatic fallback option disabled.
The sound will be cut off in case of digital signal failure on input pair AB, but it will
automatically be recovered when the signal has returned to normal state.
Automatic fallback option enabled.
Input pair CD will automatically be selected in case of digital signal failure on input pair AB.
Revert to input pair AB is not automatic and must be done manually by the user.
Figure 36: Selecting the fallback mode
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