Output Audio Clicks And Pops; Received Audio Has Dropouts; Audio Pumps And Breathes - Linear Acoustic AERO.one V3 User Manual

Linear Acoustic AERO.one V3 User Guide
6.1.3

Output Audio Clicks and Pops

This could indicate that the AES Reference is missing or at the wrong sample rate (the unit
expects to be locked to 48kHz). If improper reference is chosen, the Ref LED will be red
and the unit will revert to internal 48kHz reference allowing the audio to continue, but due
to the sample rate converters present on each input pair, the outputs will be asynchronous
with the inputs. The solution is to make sure that the reference is connected.
It could also mean that audio applied to the unit is not properly referenced, or that the
equipment that the AERO.one is feeding is not properly referenced. Using the master by-
pass function of the unit is a helpful way to troubleshoot this issue.
6.1.4

Received Audio Has Dropouts

The primary cause of this is the Dolby Digital AC-3 encoder not being properly referenced
with respect to the MPEG video encoder/multiplexer. This is normally accomplished very
simply by having all gear referenced to the local plant.
In some cases, such as with certain equipment from Tandberg, a special reference signal is
generated in the multiplexer and it needs to be connected back to the Dolby Digital (AC-
3) encoder and used as its reference. If the AERO.one contains the Dolby Digital encoder
option, this can be accomplished by applying the signal to Ref In and selecting External
Reference as the clock source (Setup -> I/O menu). If using an external Dolby Digital en-
coder such as the DP569, set it to "REF IN/SRC On mode. Possibly the best method is
to re-embed the encoded Dolby Digital (AC-3) signal and apply it to the MPEG encoder
via SDI. Consult your MPEG encoder reference manual for more details.
6.1.5

Audio Pumps and Breathes

Sometimes audible in less sophisticated processors or when attack and release times are
not adjusted properly. The factory presets included with the AERO.one will not cause
pumping or breathing, but if it sounds like this is happening, there are three common pos-
sible causes. First, station audio could be inadvertently pre-processed by legacy gear. The
AERO.one performs best when it receives unprocessed audio. Next, the AERO.one could
be inadvertently upmixing a program that is actually 5.1 channels (this will also cause loss
or damage to dialogue). Finally, if you are using an external Dolby Digital encoder, make
sure that the Audio Coding Mode (acmod) is set to 3/2L or 5.1 channels. If inadvertently
left in 2/0 or stereo mode, only the Left front and Right front channels would be encoded.
NOTE: If the AERO.one is installed using an external Dolby Digital (AC-3) encoder
make absolutely certain that dialnorm has been set correctly and that a setting
called "RF Overmod Protect" is set to Disabled or Off. Do not confuse this with
RF Mode DRC which should be set to Film Standard.
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Troubleshooting