Sound Reinforcement, Simplified


It is the role of the sound designer, in cooperation with the director, music director, and often the composer and orchestrator, to design a sound system that fulfills the overall concept of the production. The director may give only vague clues as to how he or she wants the show to sound: "I want it to sound natural," or "I want it to sound more green," may be the only instructions the sound designer is given. The music department may have their opinions: "We want it to sound like the CD," or "We want it loud." Many Broadway and West End designers have actually classified themselves-- not necessarily by choice; some designers are noted for their "natural" sounding shows, while others specialize in "loud" shows. The way in which the sound designer builds and manipulates the system in order to achieve a desired result or evoke a mood is often called the designer's aesthetic. The term is more easily applied to visual designers and sound designers who concentrate on sound effects and music compositions to enhance a performed work, but it still applies to designers who specialize in reinforcement.

It is extremely difficult to quantify a sound reinforcement design, but we can outline some of the factors that contribute to a design's aesthetic:

Some designers are known for their highly "natural" sounding shows, in which the audience is able to localize the sound source to the performers onstage and are blissfully unaware of the use of a sound reinforcement system. Localization is achieved through careful delay and equalizer setting. All loudspeakers are equalized and time-aligned such that the fictitious "zero reference" point is downstage center— the average location of the average actor in the average show. Other designers dynamically— throughout the performance— adjust the delay and equalization settings of different groups of loudspeakers relative to each other in order to provide for even more imaging. In these systems, performers clustered upstage-right are fed to loudspeaker systems that are referenced to an imaginary point located upstage-right, and as they move throughout the course of the show, so does this imaginary point. Still other designers prefer loudness over imaging, increasing intelligibility but sacrificing the natural, unamplified quality that some shows and directors require. The type of production and the desires of the creative staff, will play a part in the type of sound system design required. One will note with time that given a poorly-written and/or poorly-directed and/or poorly-acted show, producers will often come to the sound designer first with the admonition: "Make it louder." It is possible that with the onset of lots of money to throw at crap shows, producers lose their ability to think properly, and perhaps if that actor says that joke louder, it will be funnier.

All aspects of a theatrical production cost money, and sound design is no exception. Smaller theatre companies make the mistake of skimping on sound equipment, resulting in poorly executed sound systems and complaining patrons. It is important to remember that no matter how sturdily the sets are built, and no matter how well the actors are lit, if the audience can't hear the performers, then the audience has wasted their money. The point of a musical or drama is to tell a story. Theatre without scenery is "modern," and theatre without lighting is radio, but theatre without intelligible sound— whether produced from a human being or coming out of a loudspeaker— is mime... and nobody likes mimes.


Regardless of the desired aesthetic, there are some basic sound reinforcement structures we can examine. The size of the venue will play a large role in deciding the quantity and complexity of the sound system, but most systems can be broken down as follows (we've taken the liberty of adding some of our own nomenclature):

Most sound designers have his or her "specialty" system, and all systems have their own pros and cons, but all share one simple goal: to provide even sound coverage to the entire audience in order to effectively transmit the information in the show to every single audience member. In order to achieve this goal, it is often necessary to divide the venue into sections that will be primarily covered by different loudspeaker systems, which are fed different input signals. The loudspeaker systems should not be thought of independently, however; all loudspeakers in the system will interact with each other, and this fact must be taken into consideration to properly set up a sound system. In order to properly facilitate the even coverage of a theatre space, designers strive to minimize the distance between loudspeaker systems and their intended coverage area and use directional loudspeakers wherever appropriate.

Microphone placement is also an important concern in sound reinforcement. Not only do we want to maximize a system's acoustic gain, but we strive for even coverage at all frequencies to preserve the acoustic, natural sound of the original source. In theatrical sound design, where radio microphones have become the norm, it is also a goal of some sound designers to hide microphone positions as best as possible.

The electrical gain of every component of the sound system should be set as close to unity as possible, so that each component of the system provides as much power as is absolutely necessary without one component straining to do all the work, which contributes to distortion and noise in the system. The distance between microphone and source should be kept to a minimum; the input channel gain should be set to provide enough headroom to tackle transients from the microphone but should not be underdriven. The mixing desk faders should be set to a comfortable "0" midpoint to provide adequate gain, and the mixing desk outputs should be set such that they are not attenuating too much of the original source material. Amplifiers and processing equipment should be set to provide only the gain required.

Loudspeakers, too, should be judiciously placed not only to increase the amount of available acoustic gain— that is to say, out of the immediate pickup pattern of the microphones— but also for even coverage in the audience sections. Using loudspeakers with narrow dispersion characteristics aid the designer in “focusing” the loudspeakers to cover only a specific portion of the audience, alleviating acoustic “spill” onto the stage or areas covered by other loudspeaker systems. It is also important to take into account the venue's architectural characteristics when positioning and specifying loudspeakers; wall-sconces and audience boxes can wreak havoc with loudspeaker dispersion characteristics.


Before we can discuss the goals and design characteristics of the vocal system, we must first become familiar with the basics of the human voice as the first piece of the sound system chain. Briefly, human beings generate vocal sound via their vocal chords, which intercept air exhaled from the lungs and vibrate in order to produce a pitch. This virbating air pressure then passes through the pharynx, the mouth, and the nose; through these passages and cavities harmonics are introduced which help determine the timbre of the sound we hear and thus helps humans differentiate one voice from another.

In the case of performers it is important that they understand these facts and the necessity of voice-training. Adequate breath control helps sustain the ends of words, where the vital consonants are often situated. If these are lost then clarity suffers. Singers' voices often strain to produce adequate loudness at the extreme high and low frequencies; guttural or strident sounds result. Sadly today fewer and fewer performers are capable of clear and strong voice projection, perhaps as a result of time spent in film and television work. As a consequence, more and more reliability is placed on amplifying stage productions. In musicals where amplification is expected, the sound system cannot do all the work; the performer must understand correct microphone technique-- too little voice and the microphone is likely to pick up unwanted sounds or generate feedback in its straining to catch any level; distortion produced by working too loudly into the microphone can only be contained by expensive equipment.

When selected loudspeakers and operating equalization, it is important to understand the range of frequencies produced by the human voice. The usual fundamental frequency for males is about 125Hz, and about 210Hz for females. This would be a normal voice level, but the trained voices such as those of actors and actresses have higher values of about 140Hz and 230Hz, respectively.

The frequency range of trained voices is unsurprisingly wider than that of untrained voices and males usually have a wider range than females-- although female voices are purer, having fewer harmonics. The pitch of the voice is usually raised in emotional moments and when working in chorus. Fundamentals usually have a frequency range of 125-250Hz. Vowels, usually 350-2000Hz, and consonants 1500-4000Hz. Fundamentals of singers are: bass-- 85-340Hz, baritone-- 90-380Hz, tenor-- 125-460Hz, alto-- 130-680Hz, contralto-- 180-600Hz, soprano-- 225-1100Hz.


Many designers have discovered that a separate system of loudspeakers dedicated to reproducing the human vocal range provides the maximum flexibility necessary for good imaging, intelligibility, and natural sound reproduction. A series of main loudspeakers, often referred to as the "cluster(s)," are mounted as close to the acting talent as possible in order to preserve the illusion that the sound source is the actor, and not the black box above the stage. The cluster loudspeakers, depending on their intended coverage area, may be somewhat directional or very directional. Spill from adjacent loudspeakers fed with the same or similar program material can destructively interfere with the sound waves from the loudspeaker feeding the intended coverage area, so early consultation with the other designers and a walk-through, or site-survey of the theatre space is paramount in order to properly specify equipment. While a cluster is the easiest method of quickly reinforcing a show, larger systems incorporate other systems in order to bring the sound image closer to the actors.

Additional loudspeaker systems can usually be found on the sides of the proscenium. These loudspeakers can fill in areas left uncovered by the overhead clusters, and are also used to provide localization information— with proper sound system equalization and time offset correction, the side loudspeakers help to provide auditory cues to the listener that the sound is not coming from the cluster, overhead, and that the sound is instead emanating from the same horizontal plane as the actors. Additionally, loudspeaker mounted along the front of the stage, termed “front-fill” loudspeakers, not only help to provide the first few rows of audience with reinforced sound, but also help draw the ear towards the floor of the stage. In conjunction with a properly time-aligned cluster and proscenium loudspeakers, front-fill systems help the listener focus on the stage, on the acoustic sound source— the actor.

Systems of unobtrusive loudspeakers are often used underneath balcony overhangs. Seating areas underneath overhangs will experience a loss of intelligibility as the seating areas are no longer in the coverage pattern of any loudspeaker system. Clusters are generally used to fill in the first, upstage, section of seating, while proscenium systems fill in the sides. A dedicated system of loudspeakers, properly time-aligned to either a fictitious source or to another loudspeaker system, usually hung under the overhang, will fill in the underbalcony seating areas. Designers often choose to utilize a number of smaller loudspeakers in order to provide even coverage, reduce overall speaker volume levels, and contribute to a clean, unblemished look. While three large loudspeakers underneath the overhang would technically provide similar results, eight smaller loudspeakers will look and sound much better.

Yet other designers may utilize a number of smaller loudspeakers ringing the front of the balcony section— a set of "balcony fills" which are the equivalent of the front fills. The first few rows of seating are covered using these loudspeakers and the sound image is drawn downward to the stage because of the loudspeaker location. Visual sightlines to the stage may be impaired by what is a good "soundline;" i.e. loudspeaker boxes may appear in the stage picture and thus may not be aesthetically acceptable to, well, anyone else, so this sort of system is rather neglected.

Less is not always more in loudspeaker selection and placement. The ultimate goal is to provide even, full-frequency coverage to all seats in the auditorium; accomplishing this feat usually requires significant numbers of loudspeakers properly equalized, delayed, and balanced, but it is important to note that the more loudspeakers there are, the greater the interaction between the loudspeaker cabinets. All loudspeaker systems are directional, especially in the high frequencies, but there is no effective way to "shutter" or "iris" the sound waves emanating from a loudspeaker. It is therefore inevitable that adjacent loudspeaker systems will both constructively and destructively interfere with one another. When two loudspeakers with the same signal source are covering the same area of space, we encounter interference that is termed "comb filtering." The name comes from a picture of the resultant sound— some frequencies are accentuated while others are lost. Depending on the amplitude and the angle where the measurement is taken, the accentuated and attenuated frequencies will vary. In layman's terms, the resultant sound can be rather tinny or honky— largely unacceptable from an intelligibility point of view. Know your loudspeaker characteristics, and position the loudspeakers to minimize interaction between cabinets.


We have discussed loudspeaker position and characteristics, but the best loudspeaker systems in the world, tuned by the best engineers in the best auditorium in the world, will still sound poor if not coupled with the best input transducers as well. We speak of the microphone, the invaluable part of our sound system chain which converts acoustic energy into electrical energy. As with many things in life, you get what you pay for.

One of the first important decisions in the sound design process is what gets a microphone. Small venues may require little-to-no reinforcement of the talent, while larger venues and Broadway musicals see a miniature radio station on almost every actor. There is, of course, a medium, which was the precursor to huge radio-frequency microphone systems— area micing, or the use of localized, cabled, microphones installed unobtrusively around the acting space.

Theatrical productions which require vocal reinforcement but who do not necessarily have the time, staff, or money for wireless microphone usage should avoid them at all costs. The use of even four wireless microphones can add an incredible amount of work to even the smallest of shows. All options should be considered, evaluated, and exhausted before deciding to use wireless microphones. Factor in the cost— cheap wireless microphones will sound cheap— inevitably they will drop out or be subject to hideous radio-frequency interference if the frequencies have not been properly selected, so only high-end (read: expensive) UHF systems should be considered. Then there are the batteries: remember that the fate of the sound of your show is riding on a $1.98 9-volt battery; don't skimp here! Proper alkaline batteries from a reputable manufacturer should be replaced before every performance. Multiply (rehearsals + performances) by the number of wireless systems, add a few for spares, and multiply by the cost per unit. And then there are the microphone elements themselves. In professional musical theatre sound design, wireless microphone elements are often hidden in the hairline or over the ear; sweat, water, hairspray, and makeup are all sworn enemies of the fragile microphone diaphragm. With each new lavalier microphone costing between $250 and $450, remember that if you or your actor break it, you've just spent another chunk of cash to replace that element. Sometimes a wet microphone capsule can be resuscitated, but as this process is applied again and again, the overall resistance to moisture will diminish. Other faults can arise— the small antennæ on the transmitter can break, rendering the transmitter useless. Actors, especially inexperienced ones, are prone to dropping transmitters, and woe be you if they drop it into a toilet. And these are just the cost considerations.

Then there is the time required for an operator to learn a show. To properly mix a show, the operator must be attentive to every single syllable uttered by anyone on stage, and should know what to do to ensure that each word comes across to the audience in an intelligible fashion. The mixing process requires time and practice (not to mention a great deal of talent)— it is almost impossible to learn how to mix a show properly with only two days of technical rehearsals. The result of not enough rehearsal time is the inevitable "missed pickup," the instance in which an actor enters the stage and begins to say his lines. The audience sits expectantly, awaiting his first word, but the operator hasn't brought up that fader for any number of inexcusable reasons. The audience can't hear, and attention is drawn to the sound system and the sound operator. It isn't worth it. And what happens when an actor's microphone fails while the show is in progress? Obviously the front-of-house operator can't run backstage to fix it, so a crew of competent "deck sound" personnel must be monitoring all the wireless microphones at all times, ensuring that nothing is amiss, and preëmptively fixing any problems before the operator brings up that particular fader. Most Broadway or West End shows utilize at least two sound crew backstage, attending to actors and their microphone woes before the performance and monitoring the equipment during the show.

In the end, the choice to use wireless microphones may not be left up to the designer, especially in regional and smaller theatre environments. "Well, it's such a big house! And the cast can't sing very well! And it's a rock-and-roll show!" may be three things heard by the sound designer. Try as he or she might, the fight against wireless microphones may be futile, but as long as these considerations have been addressed and are fully understood by the creative staff, the sound designer has done the best he or she can, and should then proceed to fight for the best equipment possible given the circumstances. Broadway and West End musical theatre relies almost solely on radio microphones manufactured by Sennheiser, with some shows using Sony or Shure systems. The actual microphone elements used in these musicals are often the Sennheiser MKE-2, the Bruel & Kjaer DPA-4060, or the Countryman B-6. Your ears should be the judge in this case.


If the sound designer has been successful in his or her quest to remove wireless microphones from the discussion, the sound system is simplified, and money can be reallocated to other parts of the system. In lieu of the radio mics, we concentrate on area microphones— hardwired microphones hidden around the stage to cover a specific area of the stage; if a scene is being played upstage-right, then the microphone(s) dedicated to that area are turned on, while the other microphones are turned off to keep the noise floor low and gain-before-feedback high. Two primary categories of microphones are usually used for these situations: foot mics and shotgun mics.

Foot mics, also called floor mics, float mics, and mouse mics, were originally ordinary cardioid condenser microphones mounted to the floor and aimed upward, theoretically at the mouths of actors. Modifications to the microphones provided designers with low-profile versions, which alleviated the tubelike microphones from protuding too far above the stage lip. These same microphones were also hidden in set-pieces or hung from the flies in order to cover other areas of the stage. What we commonly refer to as foot/float/floor microphones in these days are a modification of a cardioid condenser microphone. Originally designed and patented by Crown International, a microphone capsule is suspended a few millimeters above a flat, acoustically reflective plane. When placed on a floor, the microphone capsule picks up not only the direct sound from the sound source, but also any reflections from the floor, which increases its sensitivity. Crown termed this the "Phase Coherent Cardioid," and their PCC-160 is a stock standard in sound reinforcement situations. Other companies have similar variants. The resultant sound is quite even, and with a series of five or six floor microphones laid across the front of the stage lip, even coverage to midstage can be achieved. Some equalization is usually necessary to make the voices sound more "natural," but that's your problem, not mine.

Shotgun mics, also called boom mics or rifle mics, came to us from the film and television industry. Normally mounted on fishpoles and hung just out of the camera shot to mic scenes, they are hypercardioid or supercardioid directional microphones and have found some use in theatrical sound reinforcement. Placed mid-offstage or upstage, they can help provide coverage to areas of the stage missed by the floor mics. Some have found using shotgun mics overhead provide good results; your results may vary and depend largely on the production.

By using these area micing techniques coupled with a working script detailing actor movements, a sufficient amount of acoustic gain can be achieved, providing inexpensive sound coverage to the audience. It is worth noting, however, that all the microphones in the world cannot help a hidden or whisper-quiet performance. Early consultation with the director and/or choreographer is key in order to place talent facing downstage, and, if possible, towards a microphone.


Some of us, as much as we are loathe to admit it, work in musical theatre. Note that the root of the first word is music. As important as the text and the lyrics to the songs, the music gives the audience that added bonus that often keeps them from falling asleep, as they would in a straight play. We could wax on philosophically about music and its role in society and how important it is for proper mental health, etc., etc., etc., but that is a discussion for another time. In the meantime, let us just say that it is really important.

Designers have different methods by which they approach the reinforcement of the orchestra. Some designers prefer to amplify, rather than reinforce, the orchestra by letting the least amount of acoustic energy emanate from the pit, either with copious amounts of sound insulation or by placing the orchestra in a remote location. In this fashion the designer has ultimate control over what the audience hears; the audience hears little to none of the actual acoustic instruments. Other designers prefer to utilize the acoustic characteristics of the orchestra pit and the theatre to provide a baseline acoustic image of the orchestra, and merely reinforce the orchestra and make it more dynamic. Designers are also in dispute over how to distribute the orchestra portion of the production. Some prefer to dedicate completely separate sets of loudspeakers for orchestra reinforcement, while others use the vocal system, augmented by strategically placed orchestra loudspeakers. Again, your results may vary.

In most if not all Broadway and West End musicals, every instrument has a microphone and usually a separate input channel. There are many designers who use submixers, small mini-mixers, to mic a specific section. Percussion, for example, usually requires a few microphones and sometimes it is simpler to mix four or five microphones into a single console input rather than taking up valuable mixing desk real estate with individual inputs for each microphone. Early consultation with the orchestrator and music director will facilitate micing ideas and instrument placement, but generally speaking, everyone is miced. The actual orchestration list will dictate what specific microphone models are used; let your ears be the judge! Most prefer condenser microphones, cardioid of course, for winds and strings and sometimes brass, dynamics can be used successfully on the drumkit and rock-and-roll style instruments, close-micing is generally the norm although sectional overhead micing techniques are not out of the question. Direct boxes are generally used for keyboards and other electronic instruments.

Mic positioning is key to a successful orchestral reinforcement system; unfortunately techniques used in classical recording are impractical; a stereo pair over the pit will result in horrendous amounts of feedback, and these days it is the sad truth that music directors, composers, and choreographers all expect the sound department to be able to control the individual instruments' sound level. The result is often a plethora of close-placed microphones into a multitude of inputs, allowing full sway over every nuance of the orchestra. Proper positioning, some equalization, good balance, and close cooperation with the music department are usually the keys to success.


Mixing the show seems like a simple task: an actor comes out on stage at a predetermined point in the script, and shortly thereafter, says a line. The mixer need only turn on his microphone. Right? No; not really at all. While many theatre operations have been reduced to button-pushes with the advent of computer-controlled lighting desks and stage automation systems, mixing a show is still a very human-intensive process. Why?

Let's look at our analogs in the theatrical world. Lighting instruments are locked down and pointed at a specific location onstage, and moving lights ("wobbly buckets" in the UK) are preprogrammed to move along a given path with a given color and predetermined beam spread. Regular maintenance is a necessity, but during the performance it is merely ensuring that the "go" button is triggered at the correct point to recall the preprogrammed lighting cue to create the specific mood. The lighting instruments are not affected by a change in cast, a noisier audience, or a hot and humid theatre building. Similar thoughts can be applied to stage automation: a piece of scenery is programmed to move from A to B in a given time, and does so every night at the push of a button, regardless of a full house or small house, whether or not the leading actor has a cold, or whether or not there is a small mosquito nibbling on the cellist in the orchestra pit.

However, when mixing for live theatre, we must remember the operative word: LIVE. The mixer is controlling the sound level of every single syllable uttered by any of the cast at any time. One wrong move and the entire meaning of the show can be changed or destroyed. Because the performers who are providing our mixing console with audio signal are, in fact, human, they are mutable and dynamic. The operator must accommodate for any possible changes or curve-balls the performer may throw during the course of a performance. Perhaps the leading man's dog died this morning and he's not feeling "quite up to the challenge." Proper interaction between operator and talent can head off potential surprises.

In addition, the operator controls the overall balance of sound in the theatre. A full house with noisy kids may require more sound pressure levels than a half-empty house with blue-haired patrons from Long Island; the operator may choose to be more dynamic in parts of the show than others to incite audience response and keep them entertained. The orchestra musicians are just as mutable— maybe a small furry rodent has crawled into the pit and is running around, wreaking havoc and scaring the violinists, and suddenly their instruments are six inches closer to the microphone, and that beautiful ballad is now a screeching cacophony of horsehair and rosin. The operator is always at the mercy of the performers onstage and in the pit, and must constantly adjust the relative balances of voices and instruments while still maintaining the overall aesthetic desired by the designer. The operator is a performer unto him-or-herself.

It is interesting to note that in the State of Connecticut (my home state, thank you very much), for tax purposes, sound engineers are lumped not in the same category as stage electricians or stagehands, but instead in the same category with musicians and performers. Someone was paying attention!


Signal processing is another important facet of sound design. As we have discussed before, signal processors take many forms. Dynamics processors, such as compressor/limiters or expander/gates, modify the audio signal by adjusting the characteristics of the dynamic range (amplitude, loudness) of a signal. Other units, called Dynamic Equalizers, adjust the amplitude of a specific set of frequencies. With the advent of inexpensive digital processing, digital reverberation, echo, chorus, flange, phase shift, and delay are all readily available tools. Some have their place within the actual sound reproduction system design, while some are better saved for different areas of the sound system.

Digital delays are one of the most important pieces of the sound reinforcement system. With proper use of delay lines, the sound designer can align different loudspeaker systems in order to provide the listener with the most coherent sound possible. Sound waves travel through the air at a definite speed (approximately 343ft/sec), while sound signals travel along cables and through equipment at approximately the speed of light. If




Dynamic equalizers



Many theatrical reinforcement systems are not set up in stereo. It is extremely difficult to provide proper stereo imaging information to every audience member in the house, so it's generally not even attempted. It is common to have a set of stereo loudspeakers for sound effects, but that's about it. Vocal clusters are usually mono, underbalcony delays and front fills are also usually mono, and converting all of these systems to stereo operation is not only a pain in the ass, it's expensive. And really: how many people will actually sit in the proper smattering of seats in the theatre and exclaim, "Oh, wow! That Kurzweil K2500 patch is panned left-right!" Don't stress the stereo thing; it's generally not worth it.

Some designers use reverse-panning when dealing with the orchestra. In this fashion instruments located on the house-left side of the pit are fed to a greater degree to the house-right loudspeaker, with the intent that a full, even orchestra mix will emanate from somewhere central. While this is a valiant goal, other designers have decided that simply balancing the orchestra properly creates a stunning orchestra mix.

And then there are the playback effects: it is the theory of this writer that because sound reinforcement is so difficult to quantify, and because the best sounding reinforcement system is the one that you don't notice, sound reinforcement designers have an instinctual need to occasionally come out and say "HI, MY NAME IS (xxxx), AND I'M A SOUND DESIGNER!!!" This exclamation is usually found in the form of special effects or through the use of surround loudspeakers located in the rear and on the sides of the theatre. Really loud, earth-shaking playback effects constantly reintroduce the audience to the sound designer's work, and seeing as how ninety-five percent of the audience doesn't even recognize the fact that the actors are miced, it is a valid goal. The use of reverberation and surround loudspeakers can create the sonic illusion that the audience is, for instance, trapped inside a very deep well, trapped in a sewer, or trapped in an airplane. These are all very effective parts of the soundscape, and sometimes the use of such trickery actually enhances the show. One day such effects may cause the American Theatre Wing to recognize theatrical sound designers as part of the creative team.


At any rate, playback effects for musicals are generally limited to basic practical cues— car crashes, gunshots, chirping birds, thunder, freight trains, etc., but depending on the show and the director, your results may vary. Effects for straight dramatic plays are a different beast; while they can encompass the usual practical effects, many sound designers for plays also strive to create a soundscape through the use of ambient sound effects or composed music to complement the work. The sound system design should reflect the intent of the sound effects— many designers use multichannel systems to allow the sound to "travel" through the theatre, and/or use a number of strategically-located loudspeakers to provide the illusion that a sound is coming from... OVER THERE! and then OVER THERE! Cooperation with carpenters, electrics, and props is key to creating believable sourced effects.


It is also the responsibility of the sound reinforcement designer to adequately provide loudspeaker monitoring on the actual stage so that the talent onstage can hear their proper pitch and rhythm cues. As the orchestra is customarily located in the orchestra pit in a theatre designed to project sound out of the pit and into the house— not onto the stage— it is usually necessary to place a few key loudspeakers in, on, or around the stage itself to feed the talent with a separate mix of orchestral instruments. I can only assume that in the olden days, before sound reinforcement, actors were trained to listen better, but I'm not going to go into that right now. There inevitably comes a time during technical rehearsals in which the cast complains about not hearing their musical cues or each other, the orchestra musicians complain about not hearing each other or hearing too much of each other, and other various permutations. Some forethought and advance planning can alleviate some of these circumstances.

The foldback system refers to a system of loudspeakers provided onstage to provide the talent onstage with whatever it is they think they need to hear in order to perform well. Foldback monitors for live concerts are traditionally wedge-shaped loudspeakers one sees lying at the feet of singers, and usually provide the singer with a mix of various instruments and his or her own voice; other musicians may have similar floor-mounted wedges or separate loudspeaker systems providing them with what they need to hear. In theatrical sound reinforcement, the abstract setting down of large foldback wedges on the stage is generally looked down upon, and thus designers strive to place loudspeakers in key locations at the borders of the stage. Loudspeakers can be hung from lighting towers, lighting pipes, fixed into footlight troughs at the front of the stage, hung off the pit rail, built into scenery, or built into the stage deck itself. The type of show, location of orchestra, and available space will dictate the type of preferred loudspeakers. Touring shows often use three loudspeakers per side of the stage, hung with lighting ladders, and this is often sufficient for more acoustic shows. Shows incorporating rock-and-roll style music, or scenic designs incorporating walls may call for more creative placement and selection of loudspeakers.

Foldback systems in theatre are generally fed via auxiliary sends from the mixing desk. The orchestrations, location of the orchestra, and location of the foldback loudspeakers will dictate what instruments are fed into the foldback system, and the designer should make a point of listening to the foldback system whenever possible to alleviate potential future problems. Remember that providing a mix of the entire orchestra may not be beneficial to the cause; investigating exactly what instruments are necessary to the talent onstage can provide for a much cleaner mix. The systems should be equalized and balanced as if they were any other loudspeaker system.

If head-worn lavalier microphones are worn by the performers, under no circumstances should these microphones be mixed into the foldback system. Turning up the lavalier microphones on the performers to a point where they would be helpful to hear will result in detrimental comb-filtering, and, in the extreme, much feedback. Don't do it. If handheld microphones or head-worn boom microphones are utilized, it is possible to introduce some vocals into the foldback system as necessary. Performers, especially the inexperienced, paranoid, or those used to rock-and-roll, will inevitably complain that they have difficulty hearing themselves and/or the other performers onstage. There is very little that the theatrical sound designer can do in this situation if head-worn lavalier microphones are used. It is a law of physics that cannot be broken or changed. However, consultation with talent, musical direction, and the directorial staff can all ease the pain. Especially on the first day of cast onstage, when the talent is worrying about blocking-lines-choreography-exits-flying-scenery, it is a shock to suddenly be projecting into a large barn, whereas in rehearsals a small reverberant room provided a lot of reflection. Psychological techniques can help to alleviate the problem: constant reassurance of sound quality in the house, constant reassurance that "the sound department is doing everything they can to help," and constant ego-stroking have been known to calm down the talent. The designer should also recognize that as with any process, it is a gradual change— as days of rehearsals go by, the talent may get used to the situation and stop complaining. The change from rehearsal piano accompaniment to orchestral accompaniment can also help, as the piano may have been too heavy-handed in sections where the orchestrations are light, and thus the talent does not feel the need to compete with the music.

The last resort is usually the in-ear monitor, a piece of equipment adopted from rock-and-roll. It is the opposite of a radio microphone— an earpiece, preferably custom-molded to the actor's ear, is worn during the show and fed audio via a small radio receiver worn on the actor. The audio signal feeding the transmitter base station can be anything necessary, but the more information the talent needs, the more the need for a separate monitor mixer whose sole duty is controlling and monitoring the sound signal feeding the in-ear-monitor. Have fun!


Another issue that becomes more and more evident as musical theatre evolves into rock concerts is the need for the orchestra members to properly hear each other and, in some cases, properly hear the talent onstage. As musical orchestra are becoming dominated by the synthesizer and other electronic instruments, it is increasingly difficult to keep the sound pressure levels in the orchestra pit low enough such that the musicians can hear each other. Several Broadway shows feature string players who wear earplugs, and I don't blame them. Depending on the needs of the show, it may be necessary to place a small powered loudspeaker in the pit to feed a given instrument to another musician (feeds can be taken from direct outputs on the mixing console, via an auxiliary send, or in extreme circumstances, via a monitor mixer). It is best, however, to disallow the use of powered monitors in favor of headphones and other devices that do not introduce more sound information into the pit. If everyone in the pit were given loudspeakers of each other's instruments, the microphones would be worthless, the sound would be muddy, and everyone would be very unhappy. Some complex shows require even more technological intervention; some musicians are given remote-controlled mini-mixers, with which they can create their own personalized monitor mix of instruments and possibly vocals which they listen to via headphones. These units are quite flexible and often offer a panacea to the inevitable whining and crying emanating from the orchestra pit.

It is the belief of this writer that most of the orchestra should not require an audio feed of the cast. There is a music director who can hear the cast. He or she waves a stick, and that stick should be gospel. 'nuff said.


Another issue that becomes the responsibility of the sound designer is the ubiquitous show relay or dressing room system. As the name implies, the dressing room system is a feed, usually from the mixing desk, that is delivered to a separate system of loudspeakers located backstage. The purpose of such a system is to provide backstage areas, offstage areas, technical booths, and various other locations with an audio representation of the show in order to provide actors and crew with aural cues— in other words, it tells actors at what point the show is, and thus they know how much longer they can chat with their agent on the telephone before they are needed onstage.

Some show relay systems are fed a single feed off a microphone located somewhere in the house, usually on the balcony rail. In this fashion the sound operator is less responsible for what is fed to the show relay system than if the show relay system is fed off the mixing desk.

The system is generally used with a paging amplifier, a special type of amplifier that provides a constant voltage at the loudspeaker outputs (a conventional power amplifier varies the voltage). In the United States, paging amplifiers run at 70.7V, while in Europe, they are run at 100V. Each loudspeaker on the chain is equipped with a transformer to step-down the voltage to a voltage more suitable for a loudspeaker. While sound quality suffers with the use of the transformer, the system is practical in that many loudspeakers can be fed from one amplifier output, and sound levels of the system do not change as loudspeakers are added or removed from the system. In addition, since it is a low-current system, smaller-diameter wire (18AWG or even 20AWG) can be utilized in cabling, obviating the heavy, annoying 12AWG bundles. Some venues already have such systems in-built, and simply require patching in the audio feed and turning on the system; in some cases the existing system may require augmentation using ancillary equipment.

The show relay system is also used to distribute backstage announcements. The stage manager and various other key persons (the door man, the assistant stage managers) usually have a hardwired microphone tied into the backstage show relay system to provide cast calls and announce visitors. Since paging and show relay systems are, in this writer's opinion, part of the intercommunication systems of a sound design, they will not be covered any further.

Return to the Sound Index. Continue on to Sound Reinforcement II.

Comments, Questions, and Additions should be addressed via e-mail to Kai Harada. Not responsible for typographical errors. - © 1999 - 2002 Kai Harada. 19.05.2002

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