Inovonics David IV, Installation & User Manual

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fected by PIPP* limiting. Anyway, there’s an option to turn this
novel feature off if you don’t buy any of this.
Lookahead
Limiting
The DAVID IV final limiter is a lookahead limiter, meaning that
it acts to reduce program peaks essentially before they reach it.
No, this limiter is not a member of the Psychic Friends Net-
work™, it simply introduces a short delay in the signal path so
the limiter can reduce gain before the peak comes along. The
delay is on the order of just a few milliseconds, and this tech-
nique prevents flat-top-clipping of the program waveform dur-
ing the limiter’s initial gain-reduction ‘attack’ phase.
Avoiding flat-top-clipping through the use of lookahead limit-
ing eliminates short-term (transient) intermodulation distortion
(TIM) of the program audio. Clipping, whether hard or soft, is
generally to be avoided in flat-power-bandwidth transmission,
but can be used with good success in pre-emphasized systems
such as FM broadcasting. More about this later.
Navigate to
Processing / Peak Limiting
:
PIPP*,
Normal
or ITU?
This menu first allows the selection of either the proprietary
PIPP* limiter, or a more conventional ‘normal’ limiting function
that does not include ‘waveshape-symmetry management.’ The
third choice, ITU , is a special-purpose limiting mode that en-
sures compliance with an international broadcasting standard
practiced in certain European countries. This is discussed in
detail under the next subheading.
Action of the PIPP* limiter was described earlier, and use of this
function will be predicated on how particular program material
sounds, which of course also depends on the setup of other
processing parameters. You may wish to proceed with DAVID
IV setup using the Normal limiter selection, and then assess
any advantage (or not) by switching back and forth between
Normal and PIPP* .
Limiter Drive
The
Limiter Drive
slider sets the input level to the broadband
peak controller section to determine how hard the limiter will
be working. Actual limiter gain reduction (G/R) is shown by the
front-panel
WB LIMITER
LED bargraph display. Limiter G/R will
also be influenced to a lesser degree by Multipressor settings,
so Limiter Drive should be adjusted after the Multipressor has
been roughed-in for the desired spectral composition of the
station’s signature sound.
Carrier modulation will top-out at the 100% point whenever G/R
is indicated by the
WB LIMITER
display. So, generally, the more
G/R that is shown, the more consistently program peaks will
hover near the 100% mark. Obviously, a high-energy rock for-