Engineering For Audio
Theatre
Advice from
Tony Palermo
 The
Museum of Television & Radio
(MT&R) in Los Angeles has a small radio production studio
that was really intended for talk show production. It has a
small mixing board that accommodates five microphones, two
DAT tape machines, two CD players, two analog cassette
machines and little else. However, you don't need very much
equipment to produce a radio drama. I'll describe the
minimum necessary and if you have more than that available,
good for you.
Microphones:
Dialogue Microphones:
In pictures of the golden era of radio drama, you'll see
several actors, scripts in hand, clustered in a semi-circle
around a big pillbox microphone (an RCA 44 ribbon mic).
Those ribbon mics were a big component in getting the
intimate radio sound, but are out of production today and we
have other requirements--our actors are arrayed in front
of several microphones for reasons I'll explain in a
minute. We use three Shure
SM58
uni-directional dynamic microphones for dialogue. The
SM58's are the sturdy, standard, inexpensive P.A.-style mics
seen everywhere, (they resemble a cigar with a silver golf
ball on top). We use three mics to accommodate the various
heights of our large casts (7 to 12 actors), which often mix
children and adults. The uni-directional feature of the
SM58s limits the area where the mic is sensitive to one
direction. (My apologies to the more technically savvy
readers, but some people don't understand these concepts, so
I will cover them as necessary. See Peter Elsea's Primer
on Microphones, from the University of California at
Santa Cruz's Electronic Music Studios.) A uni-directional
microphone has unique pickup patter (polar pattern). If you
can imagine a balloon stemming out from the top of the
microphone, that is the area where the mic is most
sensitive. It is very in-sensitive in the area
directly behind the mic--where the cord is plugged in.
Pointing the mic away from some areas allows us to
keep our mics from picking up unwanted sounds, such as the
sound effects--which have their own mic.
I use mic stands with booms instead of straight-up
stands, this way the actors can't accidentally step on the
base of the stand and make a bump sound during production. I
generally have my actors speak 8-14 inches from the mic. Any
further and then we have to turn up the mic too much which
brings too much "room tone"--along with air conditioning,
etc. A small hoop wrapped with nylon mesh, called a pop
filter, can allow actors to get closer to the mic without
"popping" their P's. At the MT&R, we use 8-inch diameter pop
filters due to our large casts and they really get the
actors at the proper distance from the microphone. Pop
Filters cost about $24-$30 and are available from musical
instrument stores and the Markertek A/V supply house
http://www.markertek.com.
We've also recently started using DBX 166 electronic
limiter devices (sort of a automated volume control) to keep
the voice levels consistent.
We pair up our performers by height and assign groups to
one mic. I try to have them speak into the mic from about a
foot away, if you are much further back. you will hear the
"room tone," which may not be desirable. If the script calls
for a scream or shouted line, I tell the actors to shout up
towards the ceiling. It's preferable to have two performers
in the same scene be at the same mic since that makes their
conversation more convincing, but sometimes you have to
separate them. When two actors are at one mic, we control
their volume with distance--we move quiet actors in closer
and have louder ones stand further away--though not far
enough to make the audience feel somebody is speaking from
far away--we use that technique as an effect when called for
by the script.
The group method is not the only way to mic for radio
drama. The great Norman Corwin--who started doing radio
drama in 1938, today uses a separate mic for each
actor--even when he has a cast of 26! That's ideal, but your
production facilities (or engineer's abilities) may not
rival Norman's. I find three mics sufficient. We just keep
shuffling actors to the mic as needed. Since it's generally
confusing in radio drama to have more than four voices
talking at once, three mics do the job nicely.
Special Uses of Dialogue Microphones:
We usually reserve one of our three dialogue mics for use
with an effects device--either a tone-control-style filter
to sound like a telephone voice, or a reverb to sound like
somebody is in a deep cavern or that we're listening to
somebody's thoughts--an interior monologue. Some of our
scripts have actors speaking with a normal tone, say Lois
Lane in her office, while she's on the phone with Clark
Kent, whose voice is filtered to sound like it's coming out
of a tiny telephone handset speaker. When we use this
telephone technique, we also arrange the microphones so
Lois' mic points 180 degrees away from where Clark's
filtered mic is. In the following diagram, ----o
is a microphone, with the dotted line representing the body
of the mic and the circle representing the front of the
mic--the silver golf-ball part.
Lois o---- (normal mic faces Lois)
(filtered mic faces Clark) ----o Clark
This makes use of the SM58's uni-directional feature to
prevent Clark's normal-sounding voice, as heard in the
studio, from "leaking" into Lois's mic and undercutting the
sound of his filtered, telephone-style sound.
Microphone Effects Devices:
Some radio scripts require characters to be talking on
the phone, in a cavern or from behind a door. This requires
changing the sound of the actors voices to convince the
audience of these facts. The classic radio thriller, The
Shadow, used a telephone-style voice to signify when the
main character was invisible (on radio!). These kind
of effects require some technical trickery. For the muffled,
distant voice behind a closed door, have the actor step back
from the mic and speak into a cigar box missing one side.
For phone voices, I've had actors hold their noses while
speaking or had them speak through a paper towel tube or had
the actor speak into a coffee mug or large hard-plastic soda
cup near the mic. Now we use electronic devices that produce
a much better simulation. We do this by running our mics
through several different "black boxes" which are commonly
available to rock musicians.
For telephone-style voices, you need to take the
normal sound of the actor's voice, cut all the bass
frequencies and boost the higher frequencies. A cheap way to
approximate the sound is to have the actor talk into a
coffee mug or deep plastic tumbler held besides their mouth
and close to the microphone. The professional way to do this
is via an electronic tone control.
Some mixing boards will allow you to cut the bass and
boost the highs and "thin" out the sound; However, the
MT&R's board had no tone controls and other sound board tone
controls may not cut or boost enough (A 15 dB boost/cut is
typically used to approximate telephone voice effects). But
even with a mixing board EQ, the sound isn't convincing. (I
built a special telephone
filter mic out of 1960s phone elements and I offer those
for sale at The RuyaSonic.com Depot.)
In the old radio scripts this telephone voice sound was
called a "filtered voice" or indicated as (FILTER). Here's a
script sample:
CLARK KENT:
(FILTER) Lois? I'm calling from a phone booth...
For cavern sounds we originally tried having the
actors stand quite far away from the mic, but the actual
size of our studio wasn't big enough to sound like a very
large cave. Some modern mixing boards have digital
reverb effects built in. Our board doesn't, so we use an
external MR-1 reverb device made by
ART. It is a $120
electronic device about the size of paperback book used to
provide various room-size simulations for guitars and drums.
The MR-1 is now out of production, but other companies
make similar, inexpensive reverb boxes. We plug a mic into
this black box on one end, and plug a mic cable out of the
box and into our mixing board.
NOTE: Both black boxes require a 1/4 inch plug
input--which means the cable coming out of the mic must plug
into a Low-to-High impedance transformer adapter (a $15 hot
dog sized device) to convert the mic's signal for use in the
black box. We use a transformer to convert high impedance
signals to low impedance, made by
Whirlwind, but
you could find other transformers at Radio Shack or most
musical instrument shops. The reverb device also
requires that we use a special ($10) adapter cable made by
Hosa Technologies
that is XLR "male" on one end and 1/4 inch "phone" (male) on
the other. If you need help with getting the right wires and
adapters, print out this page and go to a musical instrument
store and ask them--this is all commonly available
equipment. Please be sure the devices you buy can accept the
low electrical signals generated by microphones--a lot of
these effect boxes are intended for electric guitars which
put out more "juice" than microphones are capable of. Some
may require that you boost the mic signal with a pre-amp
before running it through the effects device. If you don't
have a strong enough signal going into the black box, you
are liable to get hiss and distortion along with your
effected signal. Test it out before you buy.
The best route is to use a semi-pro mixing board like the
ones from Behringer
or Mackie. They can
route mics, effects devices and CD inputs any way you want.
The MT&R talk show studio doesn't have this option so we've
had to improvise with an external pre-amp.
Sound Effects Microphones:
Originally, we set up our sound effects on a couple of
cafeteria tables and placed several
Shure SM58 microphones
around them, but we soon had problems getting the right
volume for each sound effect. If a SFX artist snapped a clip
board (our gunshot sound effect) too close to the mic,
it would blow out the dialogue. If the crinkling plastic bag
was held too far away, you couldn't tell it was supposed to
be a fire. And as the show progressed through different
sound effects, the engineer would go crazy trying to balance
the several mics depending upon how loud the effects were.
In short, it was a nightmare.
We then switched to using a single omnidirectional
microphone and that did the trick! All the sound effects
could be heard easily--distance wasn't as critical with an
omnidirectional mic since it picked up all the sounds
around the mic. We use a
Shure SM63
Omnidirectional dynamic mic [We got it for $140 from
Markertek
http://www.markertek.com]. The point here is to use an
Omnidirectional mic. Not only does it pick up all the
sound within 10 feet of the mic, it also picks up a
goodly amount of the "room tone," imparting an ambiance
to the sound effects that make them "sit" better when you
listen to the radio drama. In real life, sounds are
nearby, not "in your face" and the omni mic gives you
that. Uni-directional mics put the sound effects too
close--resulting in an unnatural sound. This change
simplified our engineer's job tremendously.
Just as we use the reverb devices to make the actors
sound like they are in a cavern or having an interior
monologue, we also put the sound effects microphone through
a reverb to give them a different quality. All the advice
above regarding black boxes and adapters applies here too.
However, we use a second reverb device just for the
sound effects, so we can control the amount of reverb
separately from the dialogue reverb. The amount of reverb
can be adjusted with a knob on the black box from none at
all (called "dry") to way too much reverb ("wet"). We've
found that if the dialogue is too wet, audiences have a hard
time understanding what's being said, but sound effects need
to be a bit wetter than the dialogue for the cavern-effect
to be convincing. However, please note that if the
sound effects get too wet, they become mere "noise" and lose
their effectiveness. If your audio is not clear--the
audience loses their focus and your drama will suffer--they
could even tune to another station.
When using a microphone with an effect, we often have
actors step from one mic to another depending upon if they
use the effect or not--like if a character is using reverb
to introduce a flashback, but then appears without reverb
during the flashback. I always mark their script with
[REVERB] or [DRY] to keep them straight. (However, under
trying circumstances, this method has it's drawbacks. Once I
had to play both the Shadow AND the villain and had a heck
of a time when the filtered Shadow voice (signifying
that he was invisible) had to spar with the dry villain's
voice. In fact, after a few lines where I was running
between the dry and filtered mics, I got confused and the
villain turned invisible--to the ear, anyway.)
Mixing Consoles
The MT&R production studio came with a "broadcast" mixing
console--although it isn't particularly suited for radio
drama. You should look into a mixer that has several inputs
(for each mic as well as your music playback devices) along
with tone controls and the ability to send/return effects
devices. Putting the effects devices through such a
dedicated "effects loop" is a much better way to control
noise and effects levels (wet/dry) than putting the device
"in-line" from the mic to the sound board input. Most music
production mixers, such as those from Mackie, Tascam and
Panasonic will have these valuable features. Headphone mixes
for at least the director and sound effects people are
desirable. Behringer
offers quiet, inexpensive mixers well suited to producing
radio drama--live or in the studio, several come with
built-in reverbs and other effects.
Music Cues
We use between 13 and 20 music "cues" per
program--everything from the program themes and episode
intros to "stings," music beds and even some car driving
sound effects. For more information about finding
and using music cues, see my page
Fitting Music to Radio Drama.
We currently play our music cues from custom made CDs.
(CD-Rs--as in, recordable). When a music cue is
called for, we push the track number and pause button--wait
a second for it to cue up, then release the pause button to
trigger the cue. A decent home CD-player can do the job.
Fancier broadcast CD-players can even skip the between track
gaps and self-cue themselves. However, if you burn
your own CDs with music cues, make sure to test them in the
intended CD-player well before production--some
CD-players won't sync up fast and some CD-players won't play
some CD-R discs at all--it depends on the blank CD-R media
and the CD-player. Also, CD-players can vary in how long a
new track is muted before it starts to play--if your track
starts at 0:00, it's possible that the first second or two
of music could be muted--yuck! Those portable walkman-style
CDs will start replaying a track if they're bumped--be
careful.
When I burn music cue CD-Rs, I always put eight seconds
of silence at the end of the track. The ending silence gives
the engineer a safety period to turn down the music channel
on the mixer before the next track starts--sometimes
engineers get busy and run out of hands. You may want to put
less silence between those tracks that must quickly play
back-to-back. For manipulating the time between tracks, I
highly recommended the now-defunct CD-Architect, the CD
burning software previously available from Sonic Foundry
http://www.sonicfoundry.com. It was perfect for cutting
radio drama cue CDs. Look for other fancy CD-R
burners--especially ones that let you manipulate the index
points. Another option is to use two CD players and two
identical CDs, then alternate between machines for every
other cue.
Before we started using CD-players, we used DAT tapes
since they had an indexing capability which allowed us
to push a button and quickly get to, say, cue #4 on a tape.
Another approach would be to use a "sampling" keyboard that
would trigger the cues from specific notes, or have a
computer play music cues as sound files in the popular MP3
format. A low-tech version would have one analog cassette
tape for each cue and swap them out between two tape
players.
I would only suggest that whatever method you use, you
may need to have two devices to play music--not for back up,
but for back-to-back playing. If a script has a battle
raging, you'll use one machine to play the battle music, but
once the battle scene ends (which can vary based upon how
fast the actors speak), you may need to play another cue
immediately and you can't wait while you swap tapes or CDs
or wait for the next CD track to be reached. If you need
super-fast triggering, use two machines.
If you use duplicate CDs to cue from, just keep your
track numbers straight. Here's how I indicate machines and
tracks for a music cue when writing a script: A is for
machine 'A' and the 5 if for CD track #5:
4. MUSIC:[A-5]
STORMY DREAMS-ESTABLISH. LET IT FINISH.
Here's what I provided for the engineer on a horror show
called "Grim Scary Tales." The numbers in parentheses
indicate how long the cue runs on the tape in
minutes:seconds. The designation BED means there will be
dialogue under the cue and BRIDGE means the music plays
between scenes with no dialogue under. The [Machine: A -#1]
indicates which CD-player and the track number for this
music cue.
MUSIC CUES: “Crusade of Terror!”
1) Grim Scary Tales Intro (BED) (0:40)
[Machine A - #1]
2) Episode Intro/Battle (BED)
(1:00) [B - #2]
3) Elsa’s theme (BED) (0:25) [A - #3]
4) Citadel Celebration (BRIDGE) (0:15)
[B - #4]
5) Stormy Dreams (BED) (0:15) [A - #5]
6) Cavern Tomb (BED) (2:10) [B -
#6]
7) Eblis theme (BED) (0:25) [A - #7]
8) Elsa Underground (BED) (1:20) [B
- #8]
9) Ghoul Attack (BED) (0:40) [A - #9]
10) Tender Garrick (BED) (0:34) [B
- #10]
11) Ascent of Eblis ((BED) 0:45) [A -
#11]
12) Rid-Go Commercial (0:33) [B - #12]
13) Grim Scary Tales Outro (BED) (0:30)
[A - #13]
Marking up the Script
The director, together with the engineer, should go over
the script and mark it up as to where, when and how long
music cues run. The designation BED means there will be
dialogue under the cue and BRIDGE means the music plays
between scenes with no dialogue under. I use two
different hi-lighter pens (one for Machine "A" and the
other for Machine "B" cues) and highlight the cues. Then I
draw a vertical line with the hi-lighter through any
dialogue or sound effects cues to show just how long the
music cue runs. Some DAT/CD machines (or cues) may need a
bit of time to begin playing--if so, we will mark the script
to begin the cue just a bit earlier than where the script
indicates.
Here's a representation--as can best be presented in HTML
of what we do. I can't show the vertical lines, but explain
where they would go, below.
(page 8 from my adaptation of Macbeth: Act 4, Scene 1)
Shakespeare On The Air
“Macbeth”
8.
1.
MACBETH: That will never be. Who can impress the
forest?
Yet my heart throbs to know one thing. Tell me,
if your art can tell so much, - shall Banquo’s issue
ever reign in this kingdom?
2.
SOUND: THUNDER.
3. MUSIC:
[A-2] WEIRD MUSIC-UP. DUCK FOR VOICES.
4. ALL WITCHES:
Seek to know no more.
5. MACBETH: I
will be satisfied. Deny me this, and an eternal
curse fall on you! Let me know!
6.
SOUND: INTENSE BUBBLING-SLOWS-STOPS. THUNDER.
7.
MACBETH: Why sinks that cauldron? And what noise is
this?
8. FIRST
WITCH: Show!
9. SECOND WITCH:
Show!
10. THIRD WITCH:
Show!
11. SOUND:
THUNDER.
12. MUSIC:
WEIRD MUSIC (BED)--FADES.
13. MUSIC: [B-3]
HERALD HORNS (BRIDGE)--DUCK.
14. NARRATOR:
Thus, the stage was set for...
(A pink hi-lighter line would be
drawn vertically from just before cue #3 to just below cue
#12.
Cue #13 would only be hi-lighted
green since the cue doesn't play under any other cues.
Note that I also included the machine
track ID [A-2, B-3] when that music cue is on one or another
machine. This simplifies the
engineer's job a good deal.)
Rehearsals
The engineer should be familiar with the music and script
before the cast and SFX crew begin the cue
rehearsals. I suggest you read along with the script and
practice triggering the music cues. Then do a second
run-through adding any reverb or filter effects. It's
important that you know your script and story. You'll be
busy enough adjusting mic volumes when the regular rehearsal
and production starts. At some recording sessions, I've had
one person watch the mixer and the other read the script and
trigger the cues. It depends on how many engineers you can
get/pay.
Engineering radio drama is not difficult if you know your
script cold. Don't make life tough for yourself by trying to
wing it.
On-Air Style Live production Vs.
Post-Production Assemblage:
This article has covered how to engineer a radio drama
produced in the "golden-age" style, where all
dialogue, music and sound effects are created in real time.
However, much of it applies to the recording of the elements
of drama that can later be manipulated in what is called
"post-production."
I choose to produce audio dramas in the old fashioned
"On-air" live style. If you have sufficient prep time and a
large enough cast and crew, you can produce your show
quickly, cheaply, and with a very realistic feel. However,
to minimize errors, this method requires a bit of
organization on the producer's part and enough rehearsal for
both cast and crew. It also relies on the music being able
to properly fill the times required by the script. I compose
my own music for my productions in such a way that it will
run just the right length for the performance.
Much more common is the style of production where the
dialogue is recorded separately and then the music and sound
effects are added in post-production. This method allows
more editorial control, but can take longer since everything
must be assembled and layered together--usually
through a computerized multi-track recorder (For PC's:
Cakewalk, Cubase, Vegas, etc. For Mac's: Pro Tools, VST,
etc.)
A drawback with the post-production method is that the
actors are performing in a vacuum--they can't hear the music
or sound effects that will accompany them and this may
result in a less expressive performance. Also extensive
cutting and pasting of dialogue lines can ruin the actors'
timing. Lastly, the amount of work required to assemble a
show bit by bit can stretch out greatly, making for a
tedious and expensive job.
A lot of people favor the intensive post-production
method, but I prefer to record my shows live into a
multi-track tape machine (a Tascam DA-88) and then dump that
into a computerized audio editing program (Cakewalk Pro
Audio). I then edit the separate tracks (music, SFX,
dialogue) by replacing bad lines with re-takes, adding in
extra sound effects and doing digital pasting of music cues
(replacing the analog playbacks that were used when
recording the whole show live). I've found that this hybrid
method gives me a "live" feel while allowing for enough
editorial control. With it, I am able to produce a high
quality program in a very short time.
For some smaller productions, I record in my home studio
directly to my computer's hard disk (using Cakewalk's new
"Sonar" software package). I then layer the music and sound
effects tracks, assembling the program, scene by scene. This
can be time-consuming, but is sometimes necessary when I
have a very low budget for cast and crew.
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