Grass Valley M-2100 - Manual (Page 74)

2-50 MMCP Installation/Operation Manual
Section 2 — System Operations
Audio Ratio Profiles
This section describes how Overs are transitioned to the Program bus—
either as part of a Preroll transition, or a hot cut to/from the Program bus.
Cut Transition—Cut in Over only
Conditions:
■ No change in audio Main sources
■ No Over currently on Program bus
■ Over is on Preset bus
If the ratio associated with the Over source is greater than 50%, then the
ratio is set to 50% immediately at cut-in time and is transitioned to the final
ratio Over the fade to under period. This yields the effect of a constant Over
level, with the main level fading under to its final level which is dictated by
the ratio setting. If the ratio associated with the Over source is 50% or less,
then an immediate cut is done to this ratio.
Cut Transition—Cut in Over and Change Main Source
Conditions:
■ Change in audio Main source
■ No Over currently on Program bus
■ Over is on Preset bus
To avoid any downstream analog pops and clicks, a main audio source cut
is upgraded to a fade-fade transition with a nominal fade interval of 100
ms. Therefore, this transition will behave identically to a fade-fade with an
Over in.
At the effective time of the beginning of the first half of the transition (con-
sidering preroll, transition hold and transition now), the old Program main
source begins a transition to silent by action of the main Program/Preset
mixer.
At the effective time of the beginning of the second half of the transition
(considering transition hold, but normally immediately upon completion
of the first half), a fade from silent to the new main source and Over, with
the Over source ratio preset to the ratio associated with the Over source, is
begun.
The audible result is a short fade down of the old Program material fol-
lowed by a short fade up from silent of both the new main source and Over
source, with the ratio preset and unchanging.