Studio monitor

This article is about studio reference loudspeakers. For onstage monitor speakers for live performances, see foldback (sound engineering).

Not to be confused with Broadcast reference monitor.

Studio monitors, also called reference monitors, are loudspeakers specifically designed for audio production applications such as recording studios, filmmaking, television studios and radio studios where accurate audio reproduction is crucial.

Among audio engineers, the term monitor usually implies that the speaker is designed to produce relatively flat (linear) phase and frequency responses. In other words, it exhibits minimal emphasis or de-emphasis of particular frequencies and the loudspeaker gives an accurate reproduction of the tonal qualities of the source audio ("uncolored" or "transparent" are synonyms), and there will be no relative phase shift of particular frequencies meaning no distortion in sound stage perspective for stereo recordings.

Beyond stereo sound stage requirements, a linear phase response helps impulse response remain true to source without encountering "smearing". An unqualified reference to a monitor often refers to a near-field (compact or close-field) design. This is a speaker small enough to sit on a stand or desk in proximity to the listener (called a "bookshelf speaker" in hi-fi parlance), so that most of the sound that the listener hears is coming directly from the speaker, rather than reflecting off of walls and ceilings (and thus picking up coloration and reverberation from the room).

As well, studio monitors are made in a more physically robust manner than home hi-fi loudspeakers; whereas home hi-fi loudspeakers only have to reproduce compressed commercial recordings, studio monitors have to cope with the high volumes and sudden sound bursts that may happen in the studio when playing back unmastered mixes.

A studio monitor made for home and project studios

Uses

Many audio engineers use monitor speakers for audio mixing and mastering tasks. This enables the engineer to mix a track that will sound pleasing on the widest range of playback systems (i.e. high-end audio, low quality radios in clock radios and "boom boxes", in club PA systems, in a car stereo or a home stereo).

Accurate sound reproduction will also mean that the engineer is less likely to miss any undesirable tonal qualities of the recording, and so can compensate for them. On the other hand, some engineers prefer to work with monitors that are known to be flawed in ways that are representative of the systems end-users are likely to be listening with. In fact, most professional audio production studios have several sets of monitors spanning the range of playback systems in the market. This may include a sampling of large speakers as may be used in movie theatres, hi-fi style speakers, car speakers, portable music systems, PC speakers and consumer-grade headphones.

Amplification: Studio monitors may be "active" (including one or more internal power amplifier(s)), or passive (these require an external power amplifier). Active models are usually bi-amplified, which means that the input sound signal is divided into two parts by an active crossover, for low and high frequency components, both parts are amplified, and then the low-frequency part is routed to a woofer and the high-frequency part is routed to a tweeter or horn. Bi-amplification is done so that a cleaner overall sound reproduction can be obtained, since signals are easier to process before power amplification. Consumer loudspeakers may or may not have these various design goals.

History

1920s and 1930s

In the early years of the recording industry in the 1920s and 1930s, studio monitors were used primarily to check for noise interference and obvious technical problems rather than for making artistic evaluations of the performance and recording. Musicians were recorded live and the producer judged the performance on this basis, relying on simple tried-and-true microphone techniques to ensure that it had been adequately captured; playback through monitors was used simply to check that no obvious technical flaws had spoiled the original recording.

As a result, early monitors tended to be basic loudspeaker cabinets. The state-of-the-art loudspeakers of the era were massive horn-loaded systems which were mostly used in cinemas. High-end loudspeaker design grew out of the demands of the motion picture industry and most of the early loudspeaker pioneers worked in Los Angeles where they attempted to solve the problems of cinema sound. Designing monitors for recording studios wasn’t a major priority.

1940s and 1950s

The first high-quality loudspeaker developed expressly as a studio monitor was the Altec 604 Duplex in 1944. This innovative driver has historically been regarded as growing out of the work of James Bullough Lansing who had previously supplied the drivers for the Shearer Horn in 1936, a speaker that had rapidly become the industry standard in motion-picture sound. He’d also designed the smaller Iconic and this was widely employed at the time as a motion-picture studio monitor.

The 604 was a relatively compact coaxial design and within a few years it became the industry standard in the United States, a position it maintained in its various incarnations (the 604 went through eleven model-changes) over the next 25 years. It was common in US studios throughout the 1950s and 60s and remained in continuous production until 1998. In the UK, Tannoy introduced its own coaxial design, the Dual Concentric, and this assumed the same reference role in Europe as the Altec 604 held in the US.

Monitor usage in the industry was highly conservative, with almost monopolistic reliance on industry “standards”, in spite of the sonic failings of these aging designs. The Altec 604 had a notoriously ragged frequency response but almost all U.S studios continued to use it because virtually every producer and engineer knew its sound intimately and were practiced at listening through its sonic limitations.

Recording through unfamiliar monitors, no matter how technically advanced, was hazardous because engineers not used to their sonic signature could make poor production decisions and it was financially unviable to give production staff expensive studio time to familiarize themselves with new monitors. As a result, pretty well every U.S studio had a set of 604’s and every European studio a Tannoy Dual Concentric or two.

However, in 1959, at the height of its industry dominance, Altec made the mistake of replacing the 604 with the 605A Duplex, a design widely regarded as inferior to its predecessor. There was a backlash from some record companies and studios and this allowed Altec’s competitor, JBL (a company originally started by 604 designer James B. Lansing), to make inroads into the pro monitor market.

Capitol Records replaced their Altecs with JBL D50 Monitors and a few years later their UK affiliate, EMI, also made the move to JBL’s. Although Altec re-introduced the 604 as the "E" version Super Duplex in response to the criticism, they now had a major industry rival to contend with. Over the next decade most of the developments in studio monitor design originated from JBL.

As recording became less and less “live” and multi-tracking and overdubbing became the norm, the studio monitor became far more crucial to the recording process. When there was no original performance outside what existed on the tape, the monitor became the touchstone of all engineering and production decisions. As a result, accuracy and transparency became paramount and the conservatism evident in the retention of the 604 as the standard for over twenty years began to give way to fresh technological development. Despite this, the 604 continued to be widely used - mainly because many engineers and producers were so familiar with their sonic signature that they were reluctant to change.

1960s and 1970s

In the late 1960s JBL introduced two monitors which helped secure them preeminence in the industry. The 4320 was a direct competitor to the Altec 604 but was a more accurate and powerful speaker and it quickly made inroads against the industry standard. However, it was the more compact 4310 that revolutionized monitoring by introducing the idea of close or “nearfield” monitoring. (The sound field very close to a sound source is called the "near-field". By "very close" is meant in the predominantly direct, rather than reflected, soundfield. A near-field speaker is a compact studio monitor designed for listening at close distances (3’-5’), so, in theory, the effects of poor room acoustics are greatly reduced.)

The 4310 was small enough to be placed on the recording console and listened to from much closer distances than the traditional large wall-(or “soffit”) mounted main monitors. As a result, studio-acoustic problems were minimized. Smaller studios found the 4310 ideal and that monitor and its successor, the 4311, became studio fixtures throughout the 1970s. Ironically, the 4310 had been designed to replicate the sonic idiosyncrasies of the Altec 604 but in a smaller package to cater for the technical needs of the time.

The 4311 was so popular with professionals that JBL introduced a domestic version for the burgeoning home-audio market. This speaker, the JBL L-100, (or "Century") was a massive success and became the biggest-selling hi-fi speaker ever within a few years. By 1975, JBL overtook Altec as the monitor of choice for most studios. The major studios continued to use huge designs mounted on the wall which were able to produce prodigious SPL’s and amounts of bass.

This trend reached its zenith with The Who’s use of a dozen JBL 4350 monitors, each capable of 125 dB and containing two fifteen-inch woofers and a twelve-inch mid-bass driver. Most studios, however, also used more modest monitoring devices to check how recordings would sound through car speakers and cheap home systems. A favourite “grot-box” monitor employed in this way was the Auratone 5C, a crude single-driver device that gave a reasonable facsimile of typical lo-fi sound.

However, a backlash against the Behemoth Monitor was soon to take place. With the advent of Punk, New Wave, Indie, and Lo-Fi, a reaction to high-tech recording and large corporate-style studios set in and do-it-yourself recording methods became the vogue. Smaller, less expensive, recording studios needed smaller, less expensive monitors and the Yamaha NS-10, a design introduced in 1978 ironically for the home audio market, became the monitor of choice for many studios in the 1980s.

While its sound-quality has often been derided, even by those who monitor through it, the NS-10 continues in use to this day and many more successful recordings have been produced with its aid over the past twenty five years than with any other monitor.

1980s-1990s

By the mid-1980s the near-field monitor had become pre-eminent. The larger studios still had large main-monitors mounted in (or on) the wall but they were now mere supplements to the small monitors sitting on the meter-bridge and were viewed as prestige items mainly there to “impress the clients” and occasionally check for low-bass anomalies. Favourite large monitors of the time were the Westlake and UREI 813, the latter design originally based on the almost ageless Altec 604 with a proprietary horn and a passive crossover network including delay circuitry to align the acoustic centers of the low- and high-frequency components. Fostex "Laboratory Series" monitors were used in a few high-end studios, but with increasing costs of manufacture, they became rare. The once dominant JBL fell into disfavour as its designs were identified with 1970s excess. The new studio landscape was bare and stripped-down and the large three or four-way monitors were hardly in keeping with this philosophy.

2000s

The main post-NS-10 trend has been the almost universal acceptance of powered monitors where the speaker enclosure contains the driving amplifiers. Passive monitors require outboard power amplifiers to drive them as well as speaker wire to connect them. Powered monitors, by contrast, are comparatively more convenient and streamlined single units, which in addition, marketeers claim a number of technical advantages. The interface between speaker and amplifier can be optimized, possibly offering greater control and precision, and advances in amplifier design have reduced the size and weight of the electronics significantly. The result has been that passive monitors have become far less common than powered monitors in project and home studios.

In the 2000s, there was a trend to focus on "translation". Engineers tended to choose monitors less for their accuracy than for their ability to “translate” – to make recordings sound good on a variety of playback systems, from primitive car radios to esoteric audiophile systems. As the mix engineer Chris Lord-Alge has noted:

Ninety-five percent of people listen to music in their car or on a cheap home stereo; 5 percent may have better systems; and maybe 1 percent have a $20,000 stereo. So if it doesn’t sound good on something small, what’s the point? You can mix in front of these huge, beautiful, pristine, $10,000 powered monitors all you want. But no one else has these monitors, so you’re more likely to end up with a translation problem.”

(Brian Knave, “Good References”, emusician, June 1, 2001; http://emusician.com/speakers/emusic_good_references/).

But it is undecided just what aids translation. Some argue that accuracy is still the best guarantee. Others feel that monitors should mimic home and car speakers. Still more believe that monitors need to be relentlessly unflattering, so that they must work hard to make recordings sound good.

Monitor vs Hi-Fi speakers

While no rigid distinction exists between consumer speakers and studio monitors, manufacturers more and more accent the difference in their marketing material. Whereas in the 1970s the JBL 4311’s domestic equivalent, the L-100, was used in a large number of homes, and the Yamaha NS-10 also served both domestically and professionally during the 1980s, there are no present-day equivalents. Professional companies such as Genelec, Klein and Hummel, Quested, PMC, and M & K sell almost exclusively to the professional monitor market, while most of the consumer audio manufacturers confine themselves to supplying speakers for the home. Even companies that straddle both worlds, like Tannoy, ADAM, Focal/JM Labs, surrounTec, Dynaudio, and JBL, tend to clearly differentiate their monitor and hi-fi lines.

Generally, studio monitors are physically robust, to cope with the high volumes and physical knocks that may happen in the studio, and studio monitors are used for listening at shorter distances (e.g., near field) than hi-fi speakers, though nothing precludes them from being used in a home-sized environment. Studio monitors are increasingly self-amplified (active), although not exclusively so, while hi-fi speakers usually require external amplification.

Many inexpensive hi-fi models are designed to make a pleasing sound by deliberately manipulating the frequency response curve of the audio signal they receive. No speaker, monitor or hi-fi, regardless of the design principle, has a completely flat frequency response; all speakers color the sound to some degree. Monitor speakers are assumed to be as free as possible from coloration.

See also

• Loudspeaker
• Loudspeaker acoustics
• List of loudspeaker manufacturers
• Digital room correction
• Room acoustics

References

External links

• Lansing Heritage This website contains comprehensive material on Altec and JBL and a history of these two companies' seminal contributions to studio monitor design.
• John Eargle: "Requirements for Studio Monitoring", 1977: Gives a good overview of state of the art monitor design at the time of publication.
• Tannoy's Greatest Hits. Covers the various editions of the Tannoy Dual Concentric.
• Bob Katz: "Level Practices (Part 2)": Discusses methods and benefits of standardized monitoring levels in film and music production.
• Phil Ward: "Monitors versus Hi-Fi Speakers For Project Studio Monitoring Pt 1": Comparison of two pro monitors and two home-audio speakers by measurement which concludes that differences between the samples were small.
• Phil Ward: "Monitors versus Hi-Fi Speakers For Project Studio Monitoring Pt 2": Comparison of two pro monitors and two home-audio speakers by measurement which concludes that differences between the samples were small.
• J. Gordon Holt: "The Search for the Ultimate Loudspeaker, Part 1: Audiophile vs. Pro Speakers & Westlake Lc8.1 ans Lc8.1SW", The Absolute Sound, 132 (Oct. 2001) Characterizes large sonic differences between professional monitors and audiophile speakers to the detriment of the latter.
• Colin Miller: "The Benefits of an Active Speaker Lifestyle", Secrets of Home Theater and High Fidelity Dec. 2002. Argues the technical and sonic benefits of active speakers.