HU-TX500-TECH
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TX500 series technical manual
Dolby-E at the nearest Dolby-E packet-boundary after the end-point of the transition. This
will be decoded as a fixed 5 millisecond cross-fade between the two signals. This is
implemented by whichever decoder is used downstream and is not a function of the 5029
mixer.
Where the PGM is Dolby-E and PST is linear-PCM, the PGM will cut to silence at the end-
point of the transition for a cross-fade, or mid-point for a V-fade. The PST will then jump to
the final setting. Most decoders implement this is as a 2-frame fade-up from silence.
Where the PGM path is linear-PCM data and the PST has Dolby-E detected, the card will
continue to operate as a standard audio mixer until a transition to the PST input is initiated.
At the beginning of the transition point the PGM will fade to silence as usual and then PST
will cut to full Dolby-E at the end of the transition. Immediately the Dolby-E signal is cut in,
any Overs will be cut out. If both signals are linear-PCM then the normal functionality is
unaffected.
5.1.3 Monitoring
Multi-level monitoring is implemented by muting the linear-PCM output whenever Dolby-E is
detected. The Monitor-output cannot decode Dolby-E itself, and as this signal is more likely
to be connected to a DAC and speaker-system, it is more useful to mute the output as soon
as the header is detected. If the monitor output is switched between a linear-PCM and a
Dolby-E signal, there could be a burst of noise from the first corrupt packet of Dolby-E up to
the full header. (Monitor-cuts are instantaneous, not video-timed). The PPM/VU metering
will show a full amplitude signal, as metering data cannot be extracted from the Dolby-E
signal. The user needs to be aware that the meters are thus not representative of the true
content.
5.1.4 Multi-level systems
Up to four levels of Multi-level system can be created, with all the usual functions, including
channel sharing across more than one level. Users need to be aware that left/right routing
options available in linear-PCM cannot be used with Dolby-E. A Dolby-E signal has to be
routed as a fixed left/right pair. Any breakaway or left/right swap will corrupt the Dolby-E
signal and produce full amplitude noise.
5.1.5 Use with a Manual Fader panel
The Manual Fader panel has similar limitations, i.e. the Voice-Over channels are ignored
when passing Dolby-E signals.
The Master-Fade-To-Black mutes the Dolby-E signal only when the fader is at zero, as soon
as it is lifted off the bottom end-point, the signal is cut back in at full amplitude, although
decoders interpret this as a two frame fade-up.
