Studio monitor
Among audio engineers, the term monitor 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, the loudspeaker gives an accurate reproduction of the tonal qualities of the source audio ("uncolored" and "transparent" are synonyms), and there will be no relative phase shift of particular frequencies—meaning no distortion in sound-stage perspective for stereo recordings.
Loudspeakers are also required at various points in the audio processing chain to enable engineers to ensure that the programme is reasonably free from technical defects, such as audible distortion or background noise.
[3] However, as a public broadcaster dealing with a lot of live material, the BBC holds the view that studio monitors should be "as free as possible from avoidable defects".
[3] In fact, most professional audio production studios have several sets of monitors spanning the range of playback systems in the market.
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.
The British Broadcasting Corporation researchers conducted evaluations on as many speakers as they could obtain in around 1948, but found commercial loudspeaker makers had little to offer that met their requirements.
The BBC needed speakers that worked well with program material within real professional and domestic settings environments, and not just fulfil technical measurements such as frequency-response, distortion, monitors in anechoic chambers.
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.
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.
Its renowned research departments invested considerable resources in determining studio monitor suited to their different broadcasting needs, and also created their own models from first principles.
There is, of course, scope for legitimate experiment in the processing of the reproduced signals in an endeavour to improve on nature, however, realism, or as near an approach to it as may be possible, ought surely to be regarded as the normal condition and avoidable departures from this state, while justified upon occasion, should not be allowed to become a permanent feature of the system.
The successful testing of a 305mm bass cone made with new thermoplastics led to development and deployment of the LS5/5 and LS5/6 monitors that occupied only 60% volume of its predecessor.
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.
The authors expressed reservations about dispersion and directionality in 2-channel systems, noting that the "face-to-face listening arrangement" was not able to give an acceptable presentation for a centrally-located observer in a domestic setting.
[6] The paper concluded: The achievement of suitable directional characteristics within the aesthetic and economic limitations applying to domestic equipment will however require a much greater research effort than either the corporation or the radio industry have so far been able to devote to the subject.
A near-field speaker is a compact studio monitor designed for listening at close distances (3 to 5 feet (0.9 to 1.5 m)), 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.
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.
The larger studios still had large soffit-mounted main monitors but producers and engineers spent most of their time working with near-fields.
Based on the almost ageless Altec 604 with a Time-Align passive crossover network developed by Ed Long, it included delay circuitry to align the acoustic centers of the low and high-frequency components.
Powered monitors, by contrast, are comparatively more convenient and streamlined single units, which in addition, marketeers claim a number of technical advantages.
Still more believe that monitors need to be relentlessly unflattering, so that the producer and engineer must work hard to make recordings sound good.
Companies that straddle both worlds, like ADAM, Amphion Loudspeakers, ATC, Dynaudio, Focal/JM Labs, JBL, PMC, surrounTec and Tannoy tend to clearly differentiate their monitor and hi-fi lines.
