In the beginning, the term PA applied to any makeshift means of making vocals audible, typically using a pair of 12" guitar speakers, a 25 watt guitar amplifier and 'Public Address' microphones boasting a frequency response not dissimilar to British Telecom's. The cheerful simplicity of this type of setup was both acceptable because the audiences' expectations hadn't been raised by domestic Hi-Fi nor their enthusiasm lowered by a bored palate — and necessary — because in those days, bands often played several clubs in one evening! Then, in the mid-60s, the intensity of expression available to guitarists was given sharp impetus by an extraordinarily loud amplifier bearing the name Marshall, and virtually overnight guitars became predominant, leaving inaudible vocals in their wake. Up to 1967, musicians were too busy with their music to care about or even to think about PA; there was then little awareness of the crucial manner in which audiences' perception of sound could alter the nature of a concert. Musicians remained aloof and left alleged 'technicalities' in the hands of their roadies. With the benefit of hindsight, it's easy to smile at attempts by perplexed and hard-driven roadies to make loud vocals possible sans feedback using 100 watt amplifiers and speakers designed empirically for a good guitar sound rather than a Hi-Fi response. Eventually, Charlie Watkins (whose WEM guitar amplifiers and echo units had developed alongside rock'n'roll from the beginning) took the initiative and in 1967 assembled arguably the world's first high power on-the-road PA system — 1000 watts! The widely used 1kW WEM PA consisted of five 100 watt column speakers per side, driven full range by five corresponding 100 watt amplifiers; these were the very first high power transistor amps, and together with the columns, they provided a smooth if not exactly broad frequency response. But most significant of all was the WEM 'Audiomaster' mixer, which coincided with the practice of mixing the sound 'out front', amidst the audience, plus the diversification of PA from vocals only through to the wholesale miking up of instruments. Suddenly, with the discovery that close miking gave different, more dramatic sounds, it became fashionable to amplify everything through the PA, even if some instruments were quite loud enough without! Simultaneously, the concept of stage monitoring was imparted from the States, courtesy of the Who's Bobby Pridden, who persuaded Charlie Watkins to add extra mixing facilities and outputs to his Audiomasters; these lead to additional power amplifiers and monitor speakers on stage.

By 1970, and within the space of 3 years, the basis of PA as we know it today was established. This rapid development was fostered by the sudden interest of musicians, manifest most notably as competition between bands such as The Who, The Move, Pink Floyd et al to own the 'best' PA. But, equally important, the fertilisation of ideas arising from the first large scale touring of the U.S.A. by British bands was to provide the impetus for innovative British PA design in the 70s. For whilst the WEM PAs were arguably the first practical realisation of on-the-road sound systems and provided the early British festivals with unrivalled sound clarity, in a technical sense, the 'house' PAs of American venues were markedly superior.

PA from 1971 to 1981 — a Decade of Loudspeaker Politics

In 1970, Phil Dudderidge, Engineer with Led Zepellin (today a director of Soundcraft) spotted JBL and Altec house PA speakers whilst touring in the States. He wasn't the first sound engineer to be enthusiastic about the high efficiency of these horn-loaded systems, but unlike other, more dedicated roadies (Bazz Ward!) he was sufficiently keen on the idea of importing the concept of horn speakers into British PA to leave Led Zep and begin manufacturing with Paul Dobson. In turn, the evolution of this partnership led to RSD amplifiers, Studiomaster and Soundcraft mixers and the Europa Concert PA company.

In the same year, incipient heavy metal arrived from the U.S.A. to tour here in the shape of Iron Butterfly and with them came two giant eight-foot-high RCA 'W-Bins'. These bizarre horn speakers were originally designed for cinema sound systems circa WW2, and within their rapturous endorsement (their incredible loudness caused something of a sensation) was the intriguing re-discovery of 1930s and 40s cinema sound technology by the Rock business. In deference to the 'delicate' sound of Charlie Watkins' column speakers, the horn loaded designs arriving from the States were very efficient, if large hence potentially very noisy, especially in combination with burgeoning amplifier powers. But, more important, without sensitive and intelligent application, it was all too easy to generate highly coloured and distorted sound, as a 'power at all costs' syndrome developed.

Circa 1971, Steven Court made American JBL drivers widely available, and Bill Kelsey (then of Kelsey-Morris) produced PAs for bands like Ten Years After, King Crimson and T. Rex, modelled around American cinema horn designs. He also laid the foundations of the modern PA mixing desk, whilst Dave Martin relinquished his job as a recording engineer to develop commercial horn speaker stacks especially for Rock PA. Around the same time, there was friendly rivalry with Tony Andrews, who'd worked with the Pink Fairies and Piblokto, as he began to build his own speakers with an emphasis on organic development and a marked sensitivity to music.

In 1972, the first of a new generation of PAs arrived, one being supplied to Supertramp. This was the original Midas PA, designed by Jeff Byers and Chas Brooke, with advice from Scott Thompson of Colac PA hire, who'd picked up many ideas whilst touring the States. Here, for perhaps the first time, active crossovers were used, the signal being split according to frequency prior to the power amplifiers. This technique resulted in greater efficiency and had the potential for making a smooth response easier to attain. In addition, to complement the new crossover, specialised horns were used to cover the audio spectrum in three bands. We might take this for granted today, but prior to this point, PAs had only used two types of driver to cover the audio band, whilst of course, in the 60s, PAs were driven full range, with correspondingly large doses of intermodulation distortion.

Subsequently, Midas went on to specialise in the production of PA mixing desks built to studio standards and, at the same time, teamed up with Dave Martin, whose forte was to produce a standard (if unexceptional) PA speaker system. Together, Martin-Midas pioneered the concept of a 'package' PA, wherein all the components were matched. Meanwhile during 1973, Tony Andrews and Tim Isaac, working on the road as 'Sonic Trucking' produced a midrange speaker which was a radical improvement over the widely misused compression-driver loaded midrange horns prevalent at that time. Their curious invention was later dubbed the 'Turbo' by musician Tim Blake. (Later, it was to become the forerunner of what's widely regarded as the best Rock PA speaker — the Turbosound TMS3 Module.)

Early in 1975, the practice of mixing monitors on stage was established by Midas with consoles designed especially for the task, having 6, 8 or 10 outputs, so enabling each musician to have a personal monitor mix. Prior to this, the monitor signals originated from the out front desk, and even if the 4 or so monitor 'sends' provided were sufficient to cover a small band, the engineer out front was invariably too busy to give proper attention to the needs of the musos on stage.

In 1976-8, coincident with the rise of the New Wave and independent record labels, street and club musicians en masse began to acquire — or hire — elaborate PAs, made available at affordable prices. These rigs were essentially scaled down versions of large systems owned by major bands and hire companies. From this time, an unprecedented interest in PA by musicians at large developed. At the same time, prompted by the raised expectations of musician and audience alike towards PA sound quality, resulting from the now widespread ownership of domestic Hi-Fi equipment, dissatisfaction with established PA speaker systems in the classic JBL and Martin mould grew. Along with use of more refined microphones (studio types were by now often seen on stage) and desks (studio quality desks were now available from at least three manufacturers), a proliferation of Hi-Fi power amplifiers and the almost universal endorsement by major PA companies of phase correct, -24dB/octave crossovers, speaker technology suddenly stood out as an anachronism. Not only were the standard speaker systems all too eager to rip ones ears, they required wearisome twiddling with EQ knobs to achieve acceptable tonality and, moreover, their hideous black bulk was suddenly a major embarrassment: artics brimming with speaker cabinets were no longer good politics in the days of loss-making tours. Thus, a number of idiosyncratic hire companies, dissatisfied with the status quo developed highly attuned and efficient, no ear-rip, but above all compact speaker systems utilising a judicious blend of standard components. The new realism of the tightly stacked PA speakers of the late 70s is evident in Paul Weller's humorous quip as he walked around before a gig, inspecting the stage equipment — "Where's the PA?"

Towards the end of the 70s, beginning in the U.S.A. with the Clair Brothers' 'S3', full range PA cabinets began to appear. Here, instead of an untidy and/or difficult to fit together assortment of bins, horns and lenses, one or two drivers for each frequency band were mounted in a discrete and cogently shaped box, rather like a conventional 3 driver Hi-Fi cabinet. Not only did this result in a tidier and more compact stack — it also made 'flying' (hanging speakers above the stage for improved coverage in large, multi-tier auditoriums) less irksome.

So, ten years after the wholesale infusion of American techniques, the proliferation of oddly-shaped loudspeaker components has begun to revert to the simplicity of full range boxes having a surface similarity to the column speaker stacks of the 60s and, along the way, countless decibels of muddy and nauseous sound have been refined to a state where loud music can be enjoyable, at least for those who can afford state-of-the-art equipment!

PA for 1982

The implicit moral of this short history is twofold. Firstly, mistakes have been made, and it's perilous to assume that powerfully advertised and widely-used equipment is the best. Malcolm Hill has called Rock PA "A very emotional business," whilst Tony Andrews hits the nail on the head even more squarely in his observation that certain famous PA speakers have "displaced the general publics' perception of the nature of real music" — a frightening 1984'ish idea...

Musicians, then, in knowing intimately the sound of their instruments have the unique ability to make sensitive and judicious assessments about the quality of a PA, provided they have open minds, relying on their ears rather than being swayed by convention or advertising hype. If you're not a musician, or you're trying to assess synthesised sound, which has no reference point, then the key question in the absence of intimate knowledge is 'does music reproduced through this PA do things to my head?' For emphatically, good music coupled to a good PA system produces a distinct shift, a stoned gestalt wherein the sound takes on an added dimension.

Secondly, whilst 100kW PAs seem remote to the average musician, the majority of small PAs are based on techniques and hardware gleaned from the systems developed by affluent bands and entrepreneurial hire companies and, increasingly, small rigs are simply trimmed down copies of major systems. Thus, in future parts of this series, we won't ignore the techniques and innovative ideas of the large hire companies. However, from the next article, we'll concentrate predominantly on tackling the down-to-earth knowledge required by impecunious musicians to select equipment and to build and operate practical systems. Next article, we'll set off with mixing desks.