Sound reinforcement system
A sound reinforcement system is the combination of
A sound reinforcement system for a
Some audio engineers and others in the professional audio industry disagree over whether these audio systems should be called sound reinforcement (SR) systems or PA systems. Distinguishing between the two terms by technology and capability is common, while others distinguish by intended use (e.g., SR systems are for live event support and PA systems are for reproduction of speech and recorded music in buildings and institutions). In some regions or markets, the distinction between the two terms is important, though the terms are considered interchangeable in many professional circles.[4]
Basic concept
A typical sound reinforcement system consists of; input transducers (e.g., microphones), which convert sound energy such as a person singing into an electric signal, signal processors which alter the signal characteristics (e.g., equalizers that adjust the bass and treble, compressors that reduce signal peaks, etc.), amplifiers, which produce a powerful version of the resulting signal that can drive a loudspeaker and output transducers (e.g., loudspeakers in speaker cabinets), which convert the signal back into sound energy (the sound heard by the audience and the performers). These primary parts involve varying numbers of individual components[5] to achieve the desired goal of reinforcing and clarifying the sound to the audience, performers, or other individuals.
Signal path
Sound reinforcement in a large format system typically involves a signal path that starts with the signal inputs, which may be instrument
In a coffeehouse or small nightclub, the snake may be only routed to a single mixing console, which an audio engineer will use to adjust the sound and volume of the onstage vocals and instruments that the audience hears through the main speakers and adjust the volume of the
Mid- to large-size performing venues typically route the onstage signals to two mixing consoles: the front of house (FOH), and the stage monitor system, which is often a second mixer at the side of the stage. In these cases, at least two audio engineers are required; one to do the main mix for the audience at FOH and another to do the monitor mix for the performers on stage.
Once the signal arrives at an input on a mixing console, this signal can be adjusted in many ways by the sound engineer. A signal can be
Mixing consoles also have additional sends, also referred to as auxes or aux sends (an abbreviation for "auxiliary send"), on each input channel so that a different mix can be created and sent elsewhere for another purpose. One usage for aux sends is to create a mix of the vocal and instrument signals for the monitor mix (this is what the onstage singers and musicians hear from their
The processed input signals are then mixed to the master faders on the console. The next step in the signal path generally depends on the size of the system in place. In smaller systems, the main outputs are often sent to an additional equalizer, or directly to a
System components
Input transducers
Many types of input
Microphones used for sound reinforcement are positioned and mounted in many ways, including base-weighted upright stands, podium mounts, tie-clips, instrument mounts, and
Other types of input transducers include
Wireless
Wireless systems are typically used for electric guitar, bass, handheld microphones and in-ear monitor systems. This lets performers move about the stage during the show or even go out into the audience without the worry of tripping over or disconnecting cables.
Mixing consoles
Multiple consoles can be used for different purposes in a single sound reinforcement system. The front of house (FOH) mixing console is typically located where the operator can see the action on stage and hear what the audience hears. For broadcast and recording applications, the mixing console may be placed within an enclosed booth or outside in an
Signal processors
Small PA systems for venues such as bars and clubs are now available with features that were formerly only available on professional-level equipment, such as digital
Equalizers
Using equalizers, frequencies which are too weak, such as a singer with modest projection in their lower register, can be boosted. Frequencies which are too loud, such as a "boomy" sounding
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Compressors
Dynamic range compression is designed to help the audio engineer to manage the dynamic range of audio signals. Prior to the invention of automatic compressors, audio engineers accomplished the same goal by "riding the faders", listening carefully to the mix and lowering the faders of any singer or instrument which was getting too loud. A compressor accomplishes this by reducing the gain of a signal that is above a defined level (the threshold) by a defined amount determined by the ratio setting. Most compressors available are designed to allow the operator to select a ratio within a range typically between 1:1 and 20:1, with some allowing settings of up to ∞:1. A compressor with high compression ratio is typically referred to as a limiter. The speed that the compressor adjusts the gain of the signal (attack and release) is typically adjustable as is the final output or make-up gain of the device.
Compressor applications vary widely. Some applications use limiters for component protection and gain structure control. Artistic signal manipulation using a compressor is a subjective technique widely utilized by mix engineers to improve clarity or to creatively alter the signal in relation to the program material. An example of artistic compression is the typical heavy compression used on the various components of a modern rock drum kit. The drums are processed to be perceived as sounding more punchy and full.
Noise gates
A noise gate mutes signals below a set threshold level. A noise gate's function is in, a sense, opposite to that of a compressor. Noise gates are useful for microphones which will pick up noise that is not relevant to the program, such as the hum of a miked electric guitar amplifier or the rustling of papers on a minister's lectern. Noise gates are also used to process the microphones placed near the drums of a drum kit in many hard rock and metal bands. Without a noise gate, the microphone for a specific instrument such as the floor tom will also pick up signals from nearby drums or cymbals. With a noise gate, the threshold of sensitivity for each microphone on the drum kit can be set so that only the direct strike and subsequent decay of the drum will be heard, not the nearby sounds.
Effects
Reverberation and delay effects are widely used in sound reinforcement systems to enhance the sound of the mix and create a desired artistic effect. Reverb and delay add a sense of spaciousness to the sound. Reverb can give the effect of singing voice or instrument being present in anything from a small room to a massive hall, or even in a space that does not exist in the physical world. The use of reverb often goes unnoticed by the audience, as it often sounds more natural than if the signal was left "dry" (without effects).[10] Many modern mixing boards designed for live sound include on-board reverb effects.
Other effects include modulation effects such as
The appropriate type, variation, and level of effects is quite subjective and is often collectively determined by a production's audio engineer, artists,
Feedback suppressor
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Power amplifiers
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Audio engineers select amplifiers that provide enough headroom. Headroom refers to the amount by which the signal-handling capabilities of an audio system exceed a designated nominal level.[11] Headroom can be thought of as a safety zone allowing transient audio peaks to exceed the nominal level without damaging the system or the audio signal, e.g., via clipping. Standards bodies differ in their recommendations for nominal level and headroom. Selecting amplifiers with enough headroom helps to ensure that the signal will remain clean and undistorted.
Like most sound reinforcement equipment, professional power amplifiers are typically designed to be mounted within standard 19-inch racks. Rack-mounted amps are typically housed in road cases to prevent damage to the equipment during transportation. Active loudspeakers have internally mounted amplifiers that have been selected by the manufacturer to match the requirements of the loudspeaker. Some active loudspeakers also have equalization, crossover and mixing circuitry built in.
Since amplifiers can generate a significant amount of heat, thermal dissipation is an important factor for operators to consider when mounting amplifiers into equipment racks.[12] Many power amplifiers feature internal fans to draw air across their heat sinks. The heat sinks can become clogged with dust, which can adversely affect the cooling capabilities of the amplifier.
In the 1970s and 1980s, most PAs employed heavy
Digital loudspeaker management systems (DLMS) that combine digital crossover functions, compression, limiting, and other features in a single unit are used to process the mix from the mixing console and route it to the various amplifiers. Systems may include several loudspeakers, each with its own output optimized for a specific range of frequencies (i.e. bass, midrange, and treble).
Main loudspeakers
A simple and inexpensive PA
The 1970s to early 1980s was a period of innovation in loudspeaker design with many sound reinforcement companies designing their own speakers using commercially available drivers. The areas of innovation were in cabinet design, durability, ease of packing and transport, and ease of setup. This period also saw the introduction of the hanging or flying of main loudspeakers at large concerts. During the 1980s the large speaker manufacturers started producing standard products using the innovations of the 1970s. These were mostly smaller two way systems with 12", 15" or double 15" woofers and a high frequency driver attached to a high frequency horn. The 1980s also saw the start of loudspeaker companies focused on the sound reinforcement market.
The 1990s saw the introduction of
Many sound reinforcement loudspeaker systems incorporate protection circuitry to prevent damage from excessive power or operator error.
To help users avoid overpowering them, loudspeakers have a power rating (in watts) which indicates their maximum power capacity. Thanks to the efforts of the Audio Engineering Society (AES) and the loudspeaker industry group ALMA in developing the EIA-426 testing standard, power-handling specifications became more trustworthy.
Lightweight, portable speaker systems for small venues route the low-frequency parts of the music (electric bass, bass drum, etc.) to a powered subwoofer. Routing the low-frequency energy to a separate amplifier and subwoofer can substantially improve the bass response of the system. Also, clarity may be enhanced because low-frequency sounds can cause intermodulation and other distortion in speaker systems.
Professional sound reinforcement speaker systems often include dedicated hardware for safely flying them above the stage area, to provide more even sound coverage and to maximize sightlines within performance venues.
Monitor loudspeakers
Using monitor speakers instead of in-ear monitors typically results in an increase of stage volume, which can lead to more feedback issues and progressive hearing damage for the performers in front of them.[13] The clarity of the mix for the performer on stage is also typically compromised as they hear more extraneous noise from around them. The use of monitor loudspeakers, active (with an integrated amplifier) or passive, requires more cabling and gear on stage, resulting in a more cluttered stage. These factors, amongst others, have led to the increasing popularity of in-ear monitors.
In-ear monitors
In-ear monitors offer considerable isolation for the performer using them, no on-stage sound is heard and the monitor engineer can deliver a much more accurate and clear mix for the performer. With in-ear monitors, each performer can be sent their own customized mix; although this was also the case with monitor speakers, the in-ear monitors of one performer cannot be heard by the other musicians. A downside of this isolation is that the performer cannot hear the crowd or the comments from other performers on stage that do not have microphones (e.g., if the bass player wishes to communicate to the drummer). This has been remedied in larger productions by setting up microphones facing the audience that can be mixed into the in-ear monitor sends.[13]
Since their introduction in the mid-1980s, in-ear monitors have grown to be the most popular monitoring choice for large touring acts. The reduction or elimination of loudspeakers other than instrument amplifiers on stage has allowed for cleaner and less problematic mixing for both the front of house and monitor engineers. [Audio feedback is greatly reduced and there is less sound reflecting off the back wall of the stage out into vocal mics and the audience, which improves the clarity of the front-of-house mix.
Applications
Sound reinforcement systems are used in a broad range of different settings, each of which poses different challenges.
Rental systems
Audio-visual rental systems have to be able to withstand heavy use and even abuse from renters. For this reason, rental companies tend to own speaker cabinets that are heavily braced and protected with steel corners, and electronic equipment such as power amplifiers or effects are often mounted into protective road cases. Rental companies also tend to select gear that have electronic protection features, such as speaker-protection circuitry and amplifier limiters.
Rental systems for non-professionals need to be easy to use and set up and they must be easy to repair and maintain for the renting company. From this perspective, speaker cabinets need to have easy-to-access horns, speakers, and crossover circuitry, so that repairs or replacements can be made.
Many touring acts and large venue corporate events will rent large sound reinforcement systems that typically include one or more audio engineers on staff with the renting company. In the case of rental systems for tours, there are typically several audio engineers and technicians from the rental company that tour with the band to set up and calibrate the equipment. The individual that mixes the band is often selected and provided by the band, as they are familiar with the various aspects of the show and understand how the band wants the show to sound.
Live music clubs and dance events
Setting up sound reinforcement for live music clubs and dance events often poses unique challenges, because there is such a large variety of venues that are used as clubs, ranging from former
The number of
A challenge with designing sound systems for clubs is that the sound system may need to be used for both prerecorded music played by
Church sound
Churches and similar houses of worship often pose design challenges. Speakers may need to be unobtrusive to blend in with antique woodwork and stonework. In some cases, audio designers have designed custom-painted speaker cabinets. Some facilities, such as
Touring systems
Touring sound systems are available in many different sizes and shapes as they have to be powerful and versatile enough to cover many different halls and venues. Touring systems range from mid-sized systems for bands playing
Mainstream bands that are going to perform in mid- to large-sized venues during their tour schedule one to two weeks of technical rehearsal with the entire concert system and production staff, including audio engineers, at hand. This allows the audio and lighting engineers to become familiar with the show and establish presets on their digital equipment (e.g., digital mixers) for each part of the show, if needed. Many modern musical groups work with their front of house and monitor mixing engineers during this time to establish what their general idea is of how the show and mix should sound, both for themselves on stage and for the audience.
This often involves programming different effects and signal processing for use on specific songs, to make the songs sound somewhat similar to the studio versions. To manage a show with a lot of effects changes, the mixing engineers for the show often choose to use a digital mixing console so that they can save and automatically recall these many settings in between each song. This time is also used by the system technicians to get familiar with the specific combination of gear that is going to be used on the tour and how it acoustically responds during the show. These technicians remain busy during the show, making sure the SR system is operating properly and that the system is tuned correctly, as the acoustic response of a room or venue will respond differently throughout the day depending on the temperature, humidity, and number of people in the room or space.
Live theater
Sound for live theater, operatic theater, and other dramatic applications may pose problems similar to those of churches; theaters may be in heritage buildings where speakers and wiring is required to blend in with the architecture. The need for clear sightlines may make the use of regular speaker cabinets unacceptable; instead, slim, low-profile speakers are often used instead.
In live theater and drama, performers move around onstage, which means that wireless microphones may be necessary. Some of the higher-budget theater shows and musicals are mixed in surround sound live, often with the show's sound operator triggering sound effects that are being mixed with music and dialogue by the show's mixing engineer. These systems are usually much more extensive to design, typically involving separate sets of speakers for different zones in the theater.
Classical music and opera
A subtle type of sound reinforcement called acoustic enhancement is used in some concert halls where classical music such as symphonies and opera is performed. Acoustic enhancement systems add more sound to the hall and prevent dead spots in the audience seating area by "...augment[ing] a hall's intrinsic acoustic characteristics." The systems use "...an array of microphones connected to a computer [which is] connected to an array of loudspeakers." However, as concertgoers have become aware of the use of these systems, debates have arisen, because "...purists maintain that the natural acoustic sound of [Classical] voices [or] instruments in a given hall should not be altered."[14]
Kai Harada's article Opera's Dirty Little Secret states that opera houses have begun using electronic acoustic enhancement systems "...to compensate for flaws in a venue's acoustical architecture." Despite the uproar that has arisen amongst operagoers, Harada points out that none of the opera houses using acoustic enhancement systems "...use traditional, Broadway-style sound reinforcement, in which most if not all singers are equipped with radio microphones mixed to a series of unsightly loudspeakers scattered throughout the theatre." Instead, most opera houses use the sound reinforcement system for acoustic enhancement, and for subtle boosting of offstage voices, onstage dialogue, and sound effects (e.g., church bells in Tosca or thunder in Wagnerian operas).[15]
These systems use microphones, computer processing "with delay, phase, and frequency-response changes", and then send the signal "... to a large number of loudspeakers placed in extremities of the performance venue." Another acoustic enhancement system, VRAS uses "...different algorithms based on microphones placed around the room." The Deutsche Staatsoper in Berlin and the Hummingbird Centre in Toronto use a LARES system. The Ahmanson Theatre in Los Angeles, the Royal National Theatre in London, and the Vivian Beaumont Theater in New York City use the SIAP system.[16]
Lecture halls and conference rooms
Lecture halls and conference rooms pose the challenge of reproducing speech clearly in a large hall, which may have reflective,
Another challenge with doing live sound for individuals who are speaking at a conference is that, in comparison with
In some conferences, sound engineers have to provide microphones for a large number of people who are speaking, in the case of a panel conference or debate. In some cases, automatic mixers are used to control the levels of the microphones and turn off the channels for microphones that are not being spoken into, to reduce unwanted background noise and reduce the likelihood of feedback.
Sports sound systems
Systems for sports facilities often have to deal with substantial echo, which can make speech unintelligible. Sports and recreational sound systems often face environmental challenges as well, such as the need for weather-proof outdoor speakers in outdoor stadiums and humidity- and splash-resistant speakers in swimming pools. Another challenge with sports sound reinforcement setups is that in many arenas and stadiums, the spectators are on all four sides of the playing field. This requires 360-degree sound coverage. This is very different from the norm with music festivals and music halls, where the musicians are on stage and the audience is seated in front of the stage.
Setting up and testing
Large-scale sound reinforcement systems are designed, installed, and operated by audio engineers and audio technicians. During the design phase of a newly constructed venue, audio engineers work with architects and contractors, to ensure that the proposed design will accommodate the speakers and provide an appropriate space for sound technicians and the racks of audio equipment. Audio engineers will also provide advice on which audio components would best suit the space and its intended use, and on the correct placement and installation of these components. During the installation phase, audio engineers ensure that high-power electrical components are safely installed and connected and that ceiling or wall-mounted speakers are properly mounted (or "flown") onto rigging. When the sound reinforcement components are installed, the audio engineers test and calibrate the system so that its sound production will be even across the frequency spectrum.
System testing
A sound reinforcement system should be able to accurately reproduce a signal from its input, through any processing, to its output without any coloration or distortion. However, due to inconsistencies in venue sizes, shapes, building materials, and even crowd densities, this is not always possible without prior calibration of the system. This can be done in one of several ways.
The oldest method of system calibration involves a set of healthy ears, test program material (i.e. music or speech), a graphic equalizer, and a familiarity with the desired frequency response. One must then listen to the program material through the system, take note of any noticeable frequency deviation or resonances, and correct them using the equalizer. Engineers typically use a familiar playlist to calibrate a new system. This by ear process is still done by many engineers, even when analysis equipment is used, as a final check of how the system sounds with music or speech playing through the system. Another method of manual calibration requires a pair of high-quality headphones patched into the input signal before any processing.[b] One can then use this direct signal as a reference with which to identify any differences in frequency response.[17]
Since the development of digital signal processing (DSP), there have been many pieces of equipment and computer software designed to shift the bulk of the work of system calibration from human auditory interpretation to software algorithms that run on microprocessors. One tool for calibrating a sound system is a real-time analyzer (RTA). This tool is usually used by piping pink noise into the system and measuring the result with a special calibrated microphone connected to the RTA. Using this information, the system can be adjusted to help achieve the desired frequency response.
More recently, sound engineers have seen the introduction of dual fast-Fourier transform (FFT) based audio analysis software, such as Smaart, which allows an engineer to view not only frequency response information that an RTA provides, but also in the time domain. This provides the engineer with much more meaningful data than an RTA alone. Dual FFT analysis allows one to compare the source signal with the output signal. A system can be calibrated using normal program material instead of pink noise or other special test signals. Calibration can be monitored during a performance.
Equipment supply stores
Notes
- ^ In cases where performers have to play at a venue that does not have a monitor engineer near the stage, the monitor mixing is done by the FOH engineer from the FOH console. This arrangement can be problematic because the performers end up having to request changes to the monitor mixes with "...hand signals and clever cryptic phrases" which may be misunderstood. The engineer also cannot hear the changes that he is applying to the monitors on stage, often resulting in a reduction of the quality of the onstage monitor mix.[9]
- ^ The pre-fade-listen feature on the test program input channel of the mixing console, or the headphone output of the CD player or tape deck can be used for this purpose.
References
- ^ Davis, Gary; Jones, Ralph (1989), Sound Reinforcement Handbook (2nd ed.), Milwaukee: Hal Leonard Corporation, p. 4
- ^ Eargle & Foreman 2002, p. 299.
- ^ Eargle & Foreman 2002, p. 167.
- ^ Borgerson, Bruce (1 November 2003), "Is it P.A. or SR?", Sound & Video Contractor, Prism Business Media, archived from the original on 1 December 2008, retrieved 18 February 2007
- ^ Sound Equipment - Loudspeakers, Amplifiers, Signal Processors, Mixers, Music Source & Microphones Archived 2012-01-08 at the Wayback Machine. Retrieved on 2011-12-11.
- ^ Eargle & Foreman 2002, p. 62.
- ^ Badhorn, Philippe (February 2006). "Interview in Rolling Stone (France)". Rolling Stone.
- ^ Philip Manor, The Monitor Engineer's Role in Performance, archived from the original on 2008-03-25
- ^ Advantages of a Dedicated Monitor Mixing Console, Sweetwater Sound, 2004-02-16, retrieved 2019-01-07
- ^ Reverberation. Harmony-Central. Retrieved on January 23, 2009.
- ^ "Q. What exactly is 'headroom' and why is it important?". Sound on Sound. February 2010.
- LCCN lc99030654.
- ^ a b "In-Ear Monitors: Tips of the Trade". Retrieved 2009-01-24.
- ^ Why do you need a Sound System?
- ^ LiveDesignOnline.com. Kai Harada, Mar 1, 2001. Opera's Dirty Little Secret. Retrieved on March 24, 2009.
- ^ Entertainment Design, Mar 1, 2001 "PRIMEDIA Business Magazines & Media Inc". Archived from the original on 2013-10-31. Retrieved 2007-10-25.
- ^ Rat, Dave. "When Hearing Starts To Drift". Archived from the original on 2001-12-26. Retrieved 2007-04-26.
- Eargle, John; Foreman, Chris (2002). Audio Engineering for sound reinforcement. Milwaukee: Hal Leonard Corporation.
Further reading
Books
- AES Sound Reinforcement Anthology, vol. 1 and 2, New York: Audio Engineering Society, 1996 [1978]
- Ahnert, W.; Steffer, F. (2000), Sound Reinforcement Engineering, London: SPON Press, ISBN 0-419-21810-6
- Alten, Stanley R. (1999), Audio in Media (5th ed.), Belmont, CA: Wadsworth, ISBN 0-534-54801-6
- Ballou, Glen (2005), Handbook for Sound Engineers (3rd ed.), Oxford: Focal Press, ISBN 0-240-80758-8
- Benson, K. (1988), Audio Engineering Handbook, New York: McGraw-Hill, ISBN 0-07-004777-4
- Borwick, J., ed. (2001), Loudspeaker and Headphone Handbook (3rd ed.), Boston: Focal Press, ISBN 0-240-51578-1
- Brawley, J., ed. (October 1998), Audio systems Technology #2 - Handbook for Installers and Engineers, Cedar Rapids, IA: National Systems Contractors Association (NSCA), ISBN 0-7906-1163-5
- Buick, Peter (1996), Live Sound: PA for Performing Musicians, Kent, UK: PC Publishing, ISBN 1-870775-44-9
- Colloms, Martin (2005), High Performance Loudspeakers, Chichester: John Wiley & Sons, ISBN 0-470-09430-3
- Davis, D.; Davis, C. (1997), Sound System Engineering (2nd ed.), Boston: Focal Press, ISBN 0-240-80305-1
- Dickason, V. (1995), The Loudspeaker Cookbook (5th ed.), Peterborough, NH: Audio Amateur Press, ISBN 0-9624191-7-6
- ISBN 0-442-01397-3
- ISBN 1-4020-7584-7
- ISBN 0-240-51961-2
- Eiche, Jon F. (1990), The Yamaha Guide to Sound Systems for Worship, Milwaukee, WI: Hal Leonard Corp., ISBN 0-7935-0029-X
- Fry, Duncan (1996), Live Sound Mixing (3rd ed.), Victoria Australia: Roztralia Productions, ISBN 9996352706
- Giddings, Philip (1998), Audio Systems Design and Installation (2nd ed.), Carmel, Indiana: Sams, ISBN 0-672-22672-3
- JBL Professional, Sound System Design Reference Manual (PDF) (ebook ed.), Northridge, CA, 1999
{{citation}}
: CS1 maint: location missing publisher (link) - Moscal, Tony (1994), Sound Check: The Basic of Sound and Sound Systems, Milwaukee, WI: Hal Leonard Corp., ISBN 0-7935-3559-X
- Oson, H.F. (1967), Music, Physics and Engineering, New York: Dover, ISBN 0-486-21769-8
- Pohlmann, Ken (2005), Principles of Digital Audio (5th ed.), New York: McGraw-Hill, ISBN 0-07-144156-5
- Stark, Scott H (2004), Live Sound Reinforcement (Bestseller ed.), Auburn Hills, MI: Mix Books, ISBN 1-59200-691-4
- Streicher, Ron; ISBN 0-9665162-0-6
- Talbot-Smith, Michael, ed. (2001), Audio Engineer's Reference Book (2nd ed.), Focal Press, Butterworth-Heinemann Ltd., ISBN 0-240-51685-0
- Trubitt, David (1993), Concert Sound: Tours, Techniques & Technology, Emeryville, CA: Mix Books, ISBN 0-7935-2073-8
- Trubitt, Rudy (1997), Live Sound for Musicians, Milwaukee, WI: Hal Leonard Corp., ISBN 0-7935-6852-8
- Trynka, P., ed. (1996), Rock Hardware, Blafon/Outline Press, San Francisco: Miller Freeman Press, ISBN 0-87930-428-6
- Urso, Mark T. PA Systems for Small Groups (DVD). ASIN B003H1AI74.
- Vasey, John (1999), Concert Sound and Lighting Systems (3rd ed.), Boston: Focal Press, ISBN 0-240-80364-7
- Wallace, Ric, ed. (2012), Live Sound basics: The fundamentals of Live Sound for Beginners (1st ed.), Athens, GA: Amazon, ISBN 978-1475080476
- Whitaker, Jerry (2006), AC Power Systems Handbook (3rd ed.), Boca Raton: CRC, ISBN 0-8493-4034-9
- Whitaker, Jerry; Benson, K. (2002), Standard Handbook of Audio and Radio Engineering, New York: McGraw-Hill, ISBN 0-07-006717-1
- White, Glenn; Louie, Gary J. (2005), The Audio Dictionary, Seattle: University of Washington Press, ISBN 0-295-98498-8
- White, Paul (2005), The Sound On Sound book of Live Sound for the Performing Musician, London: Sanctuary Publishing Ltd, ISBN 1-86074-210-6
- Yakabuski, Jim (2001), Professional Sound Reinforcement Techniques: Tips and Tricks of a Concert Sound Engineer, Vallejo, CA: Mix Books, ISBN 0-87288-759-6
Papers
- Benson, J.E. "Theory and Design of Loudspeaker Enclosures", Amalgamated Wireless Australia Technical Review, (1968, 1971, 1972).
- Beranek, L., "Loudspeakers and Microphones", J. Acoustical Society of America, volume 26, number 5 (1954).
- Damaske, P., "Subjective Investigation of Sound Fields", Acustica, Vol. 19, pp. 198–213 (1967–1968).
- Davis, D & Wickersham, R., "Experiments in the Enhancement of the Artist's Ability to Control His Interface with the Acoustic Environment in Large Halls", presented at the 51st AES Convention, 13–16 May 1975; preprint number 1033.
- Eargle J. & Gelow, W., "Performance of Horn Systems: Low-Frequency Cut-off, Pattern Control, and Distortion Trade-offs", presented at the 101st Audio Engineering Society Convention, Los Angeles, 8–11 November 1996. Preprint number 4330.
- Engebretson, M., "Low Frequency Sound Reproduction", J. Audio Engineering Society, volume 32, number 5, pp. 340–352 (May 1984)
- French, N. & Steinberg, J., "Factors Governing the Intelligibility of Speech Sounds", J. Acoustical Society of America, volume 19 (1947).
- Gander, M. & Eargle, J., "Measurement and Estimation of Large Loudspeaker Array Performance", J. Audio Engineering Society, volume 38, number 4 (1990).
- Henricksen, C. & Ureda, M., "The Manta-Ray Horns", J. Audio Engineering Society, volume 26, number, pp. 629–634 (September 1978).
- Hilliard, J., "Historical Review of Horns Used for Audience-Type Sound Reproduction", J. Acoustical Society of America, volume 59, number 1, pp. 1 – 8, (January 1976)
- Houtgast, T. and Steeneken, H., "Envelope Spectrum Intelligibility of Speech in Enclosures", presented at IEEAFCRL Speech Conference, 1972.
- Klipsch, P. "Modulation Distortion in Loudspeakers: Parts 1, 2, and 3" J. Audio Engineering Society, volume 17, number 2 (April 1969), volume 18, number 1 (February 1970), and volume 20, number 10 (December 1972).
- Lochner, P. & Burger, J., "The Influence of Reflections on Auditorium Acoustics", Sound and Vibration, volume 4, pp. 426–54 (196).
- Meyer, D., "Digital Control of Loudspeaker Array Directivity", J. Audio Engineering Society, volume 32, number 10 (1984).
- Peutz, V., "Articulation Loss of Consonants as a Criterion for Speech Transmission in a Room", J. Audio Engineering Society, volume 19, number 11 (1971).
- Rathe, E., "Note on Two Common Problems of Sound Reproduction", J. Sound and Vibration, volume 10, pp. 472–479 (1969).
- Schroeder, M., "Progress in Architectural Acoustics and Artificial Reverberation", J. Audio Engineering Society, volume 32, number 4, p. 194 (1984)
- Smith, D., Keele, D., and Eargle, J., "Improvements in Monitor Loudspeaker Design", J. Audio Engineering Society, volume 31, number 6, pp. 408–422 (June 1983).
- Toole, F., "Loudspeaker Measurements and Their Relationship to Listener Preferences, Parts 1 and 2", J. Audio Engineering Society, volume 34, numbers 4 & 5 (1986).
- Veneklasen, P., "Design Considerations from the Viewpoint of the Consultant", Auditorium Acoustics, pp. 21–24, Applied Science Publishers, London (1975).
- Wente, E. & Thuras, A., "Auditory Perspective — Loudspeakers and Microphones", Electrical Engineering, volume 53, pp. 17–24 (January 1934). Also, BSTJ, volume XIII, number 2, p. 259 (April 1934) and Journal AES, volume 26, number 3 (March 1978).