The Switch: Eric Clapton's Last Large Tour
Full stride, five years later
Over the last eleven years, LIVE SOUND International! covered several Eric Clapton tours in Western Europe and the US. The Clapton tour loudspeaker systems always remained the same, until 2001 when some serious changes were made. What follows is an LSMAG! update on the Clapton PA upgrade.
The switch was on for Robert Collins of Concert Sound, a leading U.K.
hire company and Eric Clapton’s FOH engineer during the past thirteen
years. Following an extensive demo of an Eastern Acoustic Works (EAW)
KF900 Series rig (see Photo #1), Clapton’s “Reptile” tour broke from traditional
Clapton touring rigs, specifically the EAW KF850 Series in Europe, and
Showco Prism in the North America.
A BIG DEAL
“The decision to make the switch was a big deal, because Eric and the
production team were happy with what they had been using,” explained Curtis
Flatt of Spectrum Sound, Nashville, the hire company for the U.S. leg
of the tour. “Robert (Collins) put it all on his shoulders. If the new
system didn’t work to everyone’s satisfaction, it would have reflected
poorly on him. He bit off a huge bit of responsibility and made it happen.”
Rusty King of Spectrum resides in the U.K. and worked with Collins and
Concert Sound on some of the basics, with EAW’s David Gunness (see Photo
#2) the KF900 Series designer hopped across “the pond” to offer additional
insight.
The respective hire company principles, Tim Boyle of Concert Sound and
Ken Porter of Spectrum, shared philosophies while making refinements and
managing details. Meanwhile, EAW’s European-based technical specialist,
James Bamlett, lent his experience, specifically in creating a more “British
Sound” from the system.
“The demo process started in a smaller arena, and continued on to a bigger
outdoor space where everyone became very comfortable with the operation
and performance of the system,” Flatt continued. Following some initial
work during the demo phase, Flatt again joined Collins and company in
London during the last of a series of dates at Royal Albert Hall.
Serving as system tech, he continued through the remaining duration in
Europe before assuming the same role as the tour moved on to the U.S.,
with Spectrum supplying their KF900-based rig.
SPECIAL TALENTS
“It all starts with Eric, his hands, his voice, his person,” Flatt noted.
“His guitar is just that, joined only by a wah-wah pedal and a guitar
amp. These elements are way on top of the mix, with far less emphasis
on the lower end and bass drum.”
The mix is filled out by the tasteful accompaniment of an all-star band,
headlined by Billy Preston on Hammond B3, Andy Fairweather Low on backing
guitar and vocals, Steve Gadd on drums, Nathan East on bass and David
Sancious on piano/keys. While these contributions are largely layered
beneath Clapton, they’re still rendered distinctly.
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Clapton switched from his long-time Shure SM58 vocal mic to an Audio Technica 4054 during recent multitrack recording of shows. Flatt explains that the 4054 sounded “much better” in the production truck, specifically reducing the stage “bleed”. Further, the 4054 proved to more consistently capture Clapton’s
voice despite constant activity and movement during a show. |
No mic preamp is deployed. The mic goes directly to the Midas XL4 house
console, with a dbx 160 compressor added on the output. A strategic few
dB of compression is applied, but only during appropriate songs.
“The house system for this tour has pretty much standardized, particularly
in the U.S.,” Flatt said. “We’re playing very similar arenas, nothing
outdoors, and there’s rarely a need to change things from venue to venue
with the exception of trim height on the main arrays.”
UNIFORM SPL
Now five years old, the KF900 Series was designed to supply full-bandwidth
coverage over vast distances, with extreme pattern control via several
patented loudspeaker technologies and complex digital signal processing.
The overriding goal is attaining broadband, uniform sound pressure levels
in both the vertical and horizontal planes, at very long distances and
with tight control and focus of sound throughout the listening area.
Part of this is addressed with Phased PointSource Technology (PPST), a
Gunness development where all horns and drivers of each loudspeaker are
placed as close together as possible, so that in multiple arrays they
act as either a line array in the vertical plane or as a point source
in the horizontal plane. Close driver spacing also makes for relatively
compact enclosures.
The digital processing allows the coverage pattern to be fine tuned, with
the vertical axis actually steered. Control in the horizontal plane is
largely achieved with horn acoustics, while in the vertical plane it’s
done mostly with electronics.
Spectrum Sound played a key role in the KF900 development process, utilizing
a prototype rig with a Promise Keepers stadium tour, with Gunness traveling
along and making incremental adjustments and improvements that were incorporated
in the first production version.
The KF900 initially faced a considerable obstacle in being utilized for
dynamic concert touring applications. Specifically, a digital processing
solution with enough horsepower to optimize the system hadn’t yet been
created in a practical, road-ready form. Subsequent developments in the
DSP realm, including the BSS Soundweb processing units deployed for the
Clapton tour, altered that scope.
ARRAY STRUCTURE
The two main loudspeaker arrays utilized for this tour are topped by two
rows of KF930 long-throw low-frequency (4x15in loaded) modules, while
the third row includes two different versions of upfill (or downfill depending
on need) modules.
Dual KF914 long-throw upfill loudspeakers, making their debut on this
tour, are positioned at the onstage side of each array, providing coverage
to the furthest reaches of each arena. These are flanked by dual KF913
medium-throw modules for the upper “flanks” of the audience area. “The
KF913’s, in particular, really put it up fast at about 40degrees,” Flatt
commented.
These are followed by two rows of KF920 long-throw mid-range modules,
each with three 10-in cones loaded on separate horns, and covering the
vast majority of floor seating. A final line of KF913 modules, flipped
“right side up”, handle downfill to all but the first few seating rows.
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“I’ll be honest: you had to be a rocket scientist to run the processing
for these arrays when they were first introduced,” Flatt says. “But
now, while it still takes a lot of processing power, the factory
settings have been refined so that they’re pretty much what you
want, each time out, and then it’s just a matter of individual taste
for final settings and tweaks.” Four compact Turbosound two-way loudspeakers lined the stage front to add mid/high fill at the center. |
Large video screens flown to each side meant the main arrays couldn’t
continue to wrap back around to supply coverage to audience areas to the
sides and to some extent, the rear of the stage. Instead, small KF700
Series arrays were flown behind the video screens, with inverted KF755
downfill modules handling upper regions, dual KF750’s covering the center
and a single KF755 for downfill.
“Ideally you don’t want to split coverage, but having something as small
as the KF700 Series that can do the job in terms of output, projection,
control and matching the signature of the main arrays, has made it a whole
lot easier to accept,” Flatt observed.
Flatt also acknowledged the general misconception, likely due to its horn-loading
and overall output, that the KF940 is for long-throw applications. Spectrum
normally uses EAW KF940 horn-loaded subs with the KF900 rig, but SB1000e’s
were the choice due to familiarity among the British crew.
ORIENTATION IS EVERYTHING
EAW’s Dave Gunness has spent years in the intensive research of horns,
pattern control and beam steering, with the results of this work coming
into play in the upfill and downfill loudspeaker modules found in the
KF900 Series system. EAW has been awarded a patent (U.S. Patent Number
6,009,182) for the upfill and downfill technology invented by Gunness,
and it is also employed in the company’s KF700 Series line of touring
loudspeakers.
Both the KF913 (3x2in on a single horn) module, designed for medium-throw
applications, and the new KF914 (4x2in on a single horn), supplying longer
throw, incorporate horn designs that work in tandem with KF900 Series
intensive digital signal processing (called PPST), result in precision
upfill or downfill coverage.
Selection between upfill and downfill is simply a matter of cabinet orientation
(“upside down” or “right-side up”), and in either position, the module
fits within a standard horizontal array structure. As applied to the KF913
and KF914, the DSP helps steer coverage for listening areas that might
be significantly above the trim height of the array and/or reside in the
extreme near field.
“Particularly in arenas, there’s a subtlety in the way the coverage pattern
must fit within the room,” Gunness explains. “One particular challenge
we’ve addressed is the ability to attain quality coverage to upper level
seats both in the far and near fields.”
Upper seating areas closer to the arrays on the “sides” of the coverage
area present a very steep upward coverage angle, with this angle lessening
further out into the room. KF913 modules offer medium-throw capability
but with a more steep upward firing angle to provide the commensurate
side coverage.
Meanwhile, the longer-throw KF914 modules have a less steep upward angle
and are therefore well-suited for high-quality full-bandwidth coverage
to the “back” upper level seating sections.
Gunness developed optimum settings for a wide range of configurations
and venues, using his proprietary F-Chart modeling software. These settings
are provided to the touring company, with only minor tailoring adjustments
needed from that point.
SOUNDWEB & SIM
Control interface and loudspeaker processing parameter changes were controlled
by eight FOH networked Soundweb units linked to a host PC. The KF900’s
were run in stereo, as well as the ground support arrays and even the
subs, which are fed from the left/right bus. Both side-coverage clusters
receive mono feeds.
Three QSC RAVE 161 units, each handled sixteen channels of audio inputand
routed the digitized signal from FOH to QSC Ethernet hubs at the amp racks,
which were tucked beneath the set. Based on CobraNet technology, the RAVE
units employ standard Ethernet to transport multiple channels of high-quality,
uncompressed, digital audio in real time. The channel-carrying capacity
of CobraNet enables 128X audio channels to be carried over a single CAT5
cable, virtually eliminating the large multi-core cable traditionally
used in Performance Audio.
CyberLogic NC916 PowerPlants, formed into 16-channel blocks, supplied
up to 1,600W at 4ýs. These were also equipped with multi-pole connectors
making for simple, quick connection to the loudspeakers, and included
a 208VAC Delta 3-phase power supply to smooth the load distribution.
SIM certified, Flatt deployed a full SIM rig for each show, looking primarily
at time alignment before moving on to address anomalies unique to each
individual arena. From there, Collins made final tuning by ear. Smaart
could also be an attractive choice for tuning, but there’s not enough
capacity left at the house console to accommodate multiple reference mics.
System levels usually hovered around 107dB at FOH, although this can drop
during poignant ballads. Rather than engaging in “battle the audience,”
the sound team preferred restraint with respect to levels, and the crowd
proved to quiet accordingly, making louder songs that much more dynamic.
“The key to this entire rig is that you have to step back and simplify,”
Flatt concluded. “The more simple you make it out to be, the more simple
it is. But like other premium quality systems for very large concert applications,
you don’t send this rig out with just anyone, fly the arrays, and expect
all to be perfect.
“You need to learn the rig, understand it and be fluent in it, and then
you take it to a higher level. This is the way you have to approach any
higher-end system, including the line arrays that have recently hit the
market.
September/October 2001 Live Sound International