AUDIO
“Outdoor sound disperses into the atmosphere,
whereas in enclosed venues, it hangs around and gets
trapped in the space causing reverberation. But that
doesn’t always mean it’s more straightforward to set up
an outdoor venue,” says Dave Howden, technical
services manager for large venues at Biamp, an AV
specialist based in Oregon, USA. Howden, also a
freelance sound operator for Nascar, Monster Jam and
major US sports, describes: “Some of the biggest threats
to the clarity of sound come outside from the weather.
Wind causes the listening experience to be highly
variable, depending on its direction relative to the
sound source. Low levels of humidity of 20-30% can
cause excess attenuation of high frequencies, which
can be perceived as a duller sound. For particularly
dry environments, like those in the Middle East, it’s
possible to set the computer controls to operate at low
levels of humidity by increasing the power to the highfrequency
drivers.”
Howden explains it is virtually impossible to
remedy all the constantly changing atmospheric
conditions across a large venue with a point-source
system, which concentrates speakers in one location.
“It’s often cost-effective to have one location for
speakers, such as a scoreboard or video board, but
they could have sound throw distances of 100 to 150m
when wind and humidity impact intelligibility. It’s
better to have a distributed system with multiple
speakers scattered around and located 20 to 30m from
the crowd. They also don’t ‘spill’ as much sound,
because the individual speakers don’t need to be as
loud. But it’s a balancing act with budgets at a lot of
venues as the latter solution is much more expensive.”
Crowd control
A particular challenge for intelligibility at outdoor
venues is background noise, especially from crowds
that generate around 105 decibels. Configuration of
the system at the outset is therefore critical. When
Dave Howden is operating the permanently installed
in-house systems his role is to adapt them to the nature
of the sport. “Monster Jam and Nascar are events with
high ambient noise and it’s not responsible to compete
with the sound of the engines. You can endanger
people’s hearing, or violate noise regulations,” he says.
“Monster Jams are stop-start shows and announcers
usually wait until the engine noise has died down to
make their announcements. As a sound system
operator, your job is to make sure the system level is
appropriate,” Howden adds.
Main: Sound operators have the
difficult job of adjusting system
levels at very noisy events to
ensure announcements and
music can still be heard, but
at safe and lawful volumes
Top left: Motorsport events
such as Nascar take place
on large, open sites that are
exposed to the wind, which is a
challenge for audio intelligibility
“Monster Jam and Nascar are events with high ambient
noise and it’s not responsible to compete with the sound
of the engines. You can endanger people’s hearing,
or violate noise regulations”
Dave Howden, technical services manager, Biamp
14 www.stadia-magazine.com March 2020
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