The three microphone plots show alternate positioning strategies for miking the audience: In “Lincoln Box,” a paikr of cardioid mics is placed in the boxes on either side of the proscenium and aimed at the audience. These mics are supplemented by short shotgun or cardioid mics placed at the extreme edges of the stage.
Behind many hit records is the sound of an enthusiastic live
audience. Peter Frampton’s “Show Me the Way” and Lynyrd Skynyrd’s
“Freebird” would not be the same without the sound of a huge and
involved crowd. However, exciting audience sounds don’t just appear on
the soundtrack by accident; it takes planning and a knowledge of
audience miking setups to create the impression that listeners are
truly part of a live musical event. Going into a recording or
broadcasting session, the engineer must have a good idea of what
background audience effects he or she wants. After 25 years of
recording, I am still amazed by the constant challenges that I find in
miking audiences for live broadcasts and recordings. This article
describes some of the microphones and techniques I have found to be
successful.
To start, let’s look at the types of microphones most suitable for
audience miking. I typically select shotgun mics as a first choice,
though I also use cardioid and omnidirectional mics in certain
situations. Among shotguns, the AKG CK69-ULS is my current favorite for
getting quality audience recordings, though I have also used this mic
in other applications and regard it as a valuable all-around recording
tool. The CK69-ULS shotgun element mates with the C480B body, which
means it’s adaptable to a number of capsules manufactured by AKG
including the ever-popular CK-1 cardioid capsule. Also, the CK69-ULS
capsule has two parts, and the mic may be set up as either a long or a
short shotgun.
The AKG C647 is a small shotgun-looking hypercardioid microphone
designed primarily for podium use, but it also makes a terrific
audience microphone. It features a flexible gooseneck, is lightweight
and is very easy to clip onto just about anything. Further, the price
is right, and the off-axis characteristic is reasonably smooth.
In the “Shotgun/Cardioid” plot, pairs of cardioid and shotgun mics are placed stage-left and stage-right. Cardioid mics are aimed at the nearest segment of the audience; shotguns are aimed farther back in the audience area.
Something to remember about shotgun mics is that the
ultra-directional pattern is created through cancellation and addition;
multiple signals reach the microphone element via the many slotted
ports on the shotgun body. Inevitably, not all frequencies cancel and
add ideally, and off-axis response can be very “peaky.” A lot of
microphones measure out well on paper, and the general specification
may look great. But you have to be extremely aware of the off-axis
frequency response of your microphones, particularly in live work. A
quality microphone with good off-axis rejection will reject a lot more
unwanted rear signals, such as the P.A. This is important if you choose
to place audience microphones on the stage facing back toward the
audience, as I do. Find out what the polar pattern looks like, and if
you have an opportunity to test it, do so. Using a microphone with poor
off-axis response in live situations can result in undesirable
coloration of the overall sound of your mix.
MIC LOCATION AND POSITIONING
My typical audience miking setup includes two microphones, one on
either side of the stage, facing the audience. I try to locate them as
close to the null of the main loudspeakers as possible. By the null, I
mean to the side of any loudspeakers, not the rear where you’ll get a
fair amount of low-end energy, and not the front, where you have all
the horns and high-frequency drivers. Yes, low frequency is
omnidirectional; however, typically most of the low end is rolled out
of audience pickup mics anyway, so it’s not a major issue.
Another possible audience mic position is at the front-of-house mix
position where a stereo pair would do nicely, though signal delay
relative to the main loudspeakers and any onstage mics will be
unavoidable. (The delay can be matched during mixdown, of course, but
only if there is a mixdown-not likely for a live radio broadcast-and if
the audience tracks are recorded separately.) The room ambience picked
up on audience mics, with or without the delay between the stage and at
the front-of-house position, can be a very exciting artifact to include
in a mix.
PZM microphones, hemispherical pickup pattern, placed on front-side
walls work well in some situations. In some venues, the room geometry
may be such that neither the band nor the P.A. is sonically “visible”
to PZM mics on the front-side walls, so the audience response tracks
should sound terrific.
Another setup involves wide-spaced cardioid mics or omnis hung from
the ceiling. In low-ceilinged clubs or small venues, short shotgun mics
on the ceiling aimed across the top of the audience can provide a more
uniform audience blend. I try to group my audience pickup and take in
as many individuals as possible in that group. At the right distance,
the blend of the group becomes “tight,” and the resulting applause is
much like the sound of hard, consistent rain on the roof.
In the “Full Room” plot, the “Shotgun/Cardioid” plot is supplemented with a further pair of cardioid mics arranged in an X/Y pattern at the FOH mix position and aimed toward the stage.
However, small clubs with low ceilings can present a particularly
tough challenge. You must somehow get a picture of the audience in your
stereo spectrum without hot-spotting the one jerk in the front who is
muttering something about somebody’s dog.
OUTDOOR VENUE MIKING SETUPS
When setting up audience mics at an outdoor venue, there are three main
factors to consider. First, where is the audience? Most of the audience
is far from the stage front and the typical microphone pickup points.
There may be no convenient spot to put the microphones within the
audience area. To bring the audience to the microphones, you need to
use “long-throw,” or shotgun microphones.
Second, how do you want the audience to sound? The final mix should
have a stereo spread that is exciting and realistic, yet contains some
of the nuances of today’s more contemporary styles of mixing. I like to
spread the audience across the entire stereo spectrum, from hard left
all the way over to hard right, with equal energy in between. To make
this work, a minimum of three microphones are needed; I like to use
four. I pick four audience zones to do the work for the entire audience
and choose the zones on the basis of whether I think they will be
“intelligent,” will blend well with the rest of the mix and will
represent the most responsive portion of the audience.
For picking up sound far out into the audience, I start with AKG’s
CK69-ULS long shotguns and aim them so that the direct axis of the mic
visually “hits” the ground at a distance of 100 to 200 feet. In most
outdoor venues there is no back wall to cause reflections, so there is
no concern about aiming the microphones too high.
I’ve found various combinations of smaller AKG mini-shotguns useful
for close-up area-specific miking. For example, the AKG C647 and C580
are primarily designed for podium use, but I have found them useful in
difficult venues where placement is awkward. They sound particularly
good and are cost-effective. I often use the smaller shotguns for the
far left and far right zones in the stereo mix, whereas I typically
place the long shotguns at the 10 o’clock and 2 o’clock pan
positions.
Finally, what is the recording environment? To take a recent
example, the annual “Opera in the Park” event draws around 20,000
people to San Francisco’s Golden Gate Park, where the San Francisco
Opera kicks off its coming season with a day of highlights. From an
engineering standpoint, the environment at this particular event is
pretty awful. It’s cold in the morning, hotter than hell in the
afternoon, and the wind blows sporadically all day. Shotguns and wind
don’t go together well, but good-quality windscreens and a few well
placed DIP switches can solve the wind problem. Fortunately, the
windscreens supplied with the CK69-ULS shotguns proved very
satisfactory. Also, since the CK69-ULS is based on the C480B
preamplifier body, there are 70Hz and 150Hz roll-off switches available
(slope is more than 12dB per octave). By rolling off at 70 Hz and
dropping sensitivity by 10 dB (another onboard DIP switch), I was able
to defeat virtually all of the wind noise. This allowed us to leave the
microphones open at all times in order to pick up every response that
came from the audience.
OTHER PATTERNS, OTHER ROOMS
In a large indoor venue, it may be possible to place audience mics in
the “Lincoln boxes” on both sides of the stage. At least 20 to 30 feet
away from the audience, this mic position is usually well out of the
way of the P.A. mains and ensures minimal “hot-spotting” of
individuals. A cardioid mic will offer good off-axis rejection,
minimizing the effects of nearby reflective boundaries, and will pick
up a wide cross-section of people in front. Now combine this pair of
“short throw” cardioids with two shotgun mics aimed farther into the
audience. The shotguns will pick up a whole different section of
audience, yet they may even share the same mic stands as the cardioids.
The two mic positions, left and right, provide four mic inputs for a
good stereo sweep across your mix.
Omnidirectional microphones may also be used for audience miking,
but be careful-omnis will pick up everything, and the results can be
either great or horrible. In general, I use omnis in more ambient
spaces, where the sonic characteristics of the room are worth
capturing. My favorite omnis are the Earthworks TC30Ks; they are clean,
accurate, flat and allow me to tailor the room sound to blend with the
direct mix from the stage inputs. However, the nondiscriminatory
characteristics of omni mics can leave me at the mercy of just about
anything that goes on in the room. With a spontaneous and volatile
crowd, omni mics may not be the best choice.
HORSES FOR COURSES
Finally, there are nontechnical factors that will affect your
microphone selection and positioning choices. Every one of my projects
demands that I give the best I possibly can, and when I am doing
exacting work for discerning clients, I tend to use my best precision
microphones. On the other hand, it does not make good sense to put out
your most valuable assets when you know that stage diving is the rule.
For such events, Shure SM57s have been the audience microphones of
choice-and they do work well. I have had several pairs of Sennheisers
thrown off the stage and immersed in 18 inches of liquid mud
(Sennheiser provided great repair and a quick turnaround). I’ve also
had union engineers return microphones to me with fresh wood stage
splinters protruding from the grille covers. “I don’t know how it
happened,” they shrug.
If the object of the exercise is to record the room for the sake of
the room, then it’s anybody’s artistic call. If the object is to record
audience, to get audience response as part of a musical recording, then
the objective is to get a great recording of the performance and allow
the audience (in that performance) to add the audience’s appreciation,
not to add coloration or other distracting artifacts to the
performance. Your off-axis coloration, the type of microphones you use,
where you place them and what direction, are all going to play a part
in a large sonic equation. The laws of physics and good horse sense
will always prevail.
