In Broadcast - March 2018 - 36

www.inbroadcast.com | Vol: 8 - Issue 3 | March 2018

InForm

Broadcast Audio
Processing Strategies
Orban's Peter Lee asks: Have you ever been frustrated trying to get the desired sound for
your station? Have you ever said: "I'll know its right when I hear it," but were at a loss to
achieve that sound? Sometimes it's difficult to get the on-air sound you want...

his article aims to provide a
general guideline to managing the
sound of your station to get the results
you want. This guideline won't focus on
any specific model of audio processor
considering the variety of processing
in use, both old and new. Neither will
this article tell you how your station
should sound. Instead, this proposes a
systematic approach that you can use
for getting the desired results.
Tuning a station's audio processing
requires a demanding combination
of artistic judgment and technical
experience. The basic approach
is finding your preferred sound
incrementally, usually by adjusting
past the optimum tuning point, and
then retreating, or "backing it off".
In other words, the idea is that you
won't know that you've arrived until
you went too far.
Chances are unlikely that the first
pass of adjustments will meet your
objective. So, employ a progressive
approach to the task. Take small
steps toward the goal, rather than
attempting one huge leap since the
latter is too complex to manage and
almost certain to fail.
Subjectivity
If the general manager, programme
director and engineer have divergent
preferences, define who will be the
ultimate judge. This is an opportunity
for
positive
interdepartmental
teamwork. Unfortunately, it's also an
opportunity for sharp division. Secure
the best outcome by uniting all players
toward a common objective.
Encourage use of audience research,
if your station or group has the
resources to do it. Research is much
more reliable than depending on
the preferences of one (or a few)
individuals.

The Desired Result
There is one "right" answer - the
processing that maximises your target
audience.
However, in practise it's almost
never possible to define precisely what
that processing is, even with audience
research. Almost all processing is
therefore adjusted partly by gut
feel, relying on the preferences and
experience of those responsible for
the station's sound, and, preferably, by
adding research to the variables used
to make the decision. At one end of
the scale is minimal processing for an
on-air sound that is most faithful to the
original recording.
On the other end of the scale is
aggressive processing that may sound
quite different from the original
source. Is your target audience
aged 40 to 54 listening on a home
audiophile system, or 20 something
and listening in the car, or perhaps
women in their 30's listening in
the office? Each of these cases has
appropriate types of audio processing.
Moreover, the most appropriate
processing for your audience may
change for different parts of the day.
Good judgment must be the rule. By
comparison, it's much easier to tune
the RF section of a transmitter since
there's an objective meter indication
when tuning is ideal. There is no meter
indication of when processing is "in
tune"; you must rely on your artistic
judgment. Deciding on, and defining,
the ideal point on the scale is perhaps
the most difficult task in meeting your
objective.
Legal limitations restrict peak
modulation. Peak modulation and
perceived loudness are not alike. A
minimally processed Classical format
can have similar modulation peaks as

an aggressively processed Hot Urban
format though the latter will sound
much louder on the dial. Increasing
loudness by simply cranking the
modulation invites legal penalties;
more effective (and less costly)
alternatives exist.
Align your processing objectives to
complement the overall audience,
format and business plan. If increased
time spent listening is a priority for
your station's ratings, aggressive
processing for dial dominance is
not appropriate. But CHR and Urban
formats can often benefit from a
highly processed sound that increases
the energy level of the presentation.
Compression and equalisation can do
this; there's no reason to make the
sound overtly distorted and grungy by
excessive clipping.
System Considerations
Source equipment audio quality
(e.g., noisy analogue tape, datareduced audio sources, etc.). No audio
processor can repair source audio that
is noisy, distorted, excessively bit-rate
reduced, or suffers other maladies.
In fact, aggressive audio processing
greatly exaggerates any defects in the
source material seen by the processor.
If the unprocessed audio is faulty so
follows your on-air product.
More audio processing components
installed in your system does not
guarantee better sounding audio.
It does however; guarantee greater
difficulty in managing the audio
processing to achieve the desired
result. Adding components increases
risk of failure and often, degrades
the audio. Changes made to the
first component cause downstream
components to react in sometimesunpredictable ways. In general, it's

Peter Lee

wise to minimise components in the
audio chain.
Peak overshoot is the enemy of
perceived loudness. Every percent of
overshoot broadcast is about 0.1dB of
loudness sacrificed. Therefore, every
component in the system following
and including the broadcast audio
processor must have the lowest
possible overshoot.
Not all audio processors are created
equal. Probably the best measure of
an audio processor's performance
is how effectively it can reduce
the peak-to-average ratio without
introducing unpleasant artefacts.
In other words, how well it can
increase perceived loudness without
pumping the audio, sucking up noise,
creating weird frequency balances,
or adding objectionable graininess
or intermodulation distortion due to
excessive clipping.
Configuration
Components in the system must
be arranged to deliver the best
peak control possible (i.e., minimum
overshoot) to the transmitter.
Orban 5500

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Table of Contents for the Digital Edition of In Broadcast - March 2018