A Brief History Of Live
Two of the industry's brightest names cast their minds back and reminisce to RM about the birth of the PA system.
Guy Hawley and Bruno Wayte of Harman UK provide an anecdotal history of concert PA and its evolution. Paul White interjects occasionally.
If you're looking for a historical perspective on the development of the relatively short history of Public Address systems, you won't do much better than talking to two of the key men at JBL's UK distributor, Harman Audio - so we did just that. Sales and Marketing director Guy Hawley and Sales Manager (Sound Reinforcement Division) Bruno Wayte both have many years of experience in the professional sound reinforcement field, with corresponding knowledge and insight into the practical considerations that influenced the PA systems of today. We spoke to them at Harman's Slough HQ.
GH: (Guy Hawley) "Concert PA is, relatively speaking, a tiny industry, going back only 30 years or so, though the twists and turns in its development could fill a book. I suppose the need for rock and roll PA as we know it arose back in the mid '60s when we started to have festivals with big bands such as the Beatles and Floyd."
BW: (Bruno Wayte) "The first real concert systems were probably put together by Charlie Watkins. PA then was based on column speakers, with 4x12 models from people such as Vox, Selmer and Watkins. WEM may well have been the first people to put a little piezo horn into their columns to extend the frequency range, and things progressed from there."
GH:"A parallel development existed in cinema sound systems, and much of the technology developed for cinema use found its way into PA. Originally, the only demand for high fidelity, high power sound systems had been in the cinema, where a single stack behind the screen would provide a mono sound source. Typically, this would be a very large, very efficient two-way system with a horn-loaded bass enclosure — an Altec, Vitavox or Western Electric design — plus a multicell horn with a compression driver on it. Those were the roots of modern PA.
"Very common in early PA systems was an enclosure JBL called a 4560 — a single 15-inch, short front-loading horn directly derived from cinema systems. Cinemas used the horn loading, not so much for throw — which is one reason for using it today — but for efficiency. This was important, as the available power amplifiers in the '40s and '50s were tiny by today's standards."
PW: (Paul White) Active crossover systems must have made a tremendous difference to sound systems. When did they come in?
GH: "Active crossovers did make a huge difference, as did the introduction of the high power, solid state amplifier. But a less well-known reason for the improvement in PA-systems is that the adhesive technologies used in loudspeaker construction improved significantly, allowing the manufacturers to build drivers capable of handling large amounts of power. Before that, the cone would literally fall out of the chassis."
BW: "Most of the early, 'serious', systems used active crossovers, but they weren't like the systems we use today. Midas, for example, had the crossover built into the mixing desk. The hub of the British PA industry was then Stanhope Street in north London, with Midas and Martin Audio next door to each other. From there came BWS, the leaders in electronic crossovers."
PW: It appears that different people were working at their own ideas, almost in isolation. Is this true, or did development parallel what was going on in the States?
GH: "In all honesty, the USA wasn't known for producing finished systems. Nowadays, they have JBL, ElectroVoice and EAW doing finished systems, but the country that produced most of the earlier modular systems was the UK. We had Martin Audio, Eastmill Court and the first Turbos."
BW: The original hire companies IES and Tasco — then known as MEH — used 4560s in two-way systems, after which Dave Martin, Kelsey and Court came along with their own cabinet designs."
GH: "This took the active crossover idea to its next logical step, with specific speaker boxes built to cover specific frequency bands. The best example is probably Dave Martin's Y-bin with the 15-inch driver. Steven Court's W-bin also had its roots in the cinema, where it was used as a sub-woofer.
"When it was discovered that you could get better acoustic efficiency by splitting the signal into more frequency bands, the early-two-way systems gave way to three-way systems and dedicated mid-range cabinets started cropping up. Some of these were just a couple of 12-inch speakers in a cabinet, and this developed into things like the Phillishave, a 2x12 cabinet with a curved grille on the front that made it look like a huge electric razor, hence the name.
"Horn technology also progressed from the multi-cell designs used in the cinema, though the compression driver technology is exactly the same as Lancing and Western Electric were working on in the late '20s. Of course, there have been advances in materials technology, but the underlying principle hasn't changed. Multicell horns were replaced with radial designs, and a typical system would have bass bin, a midrange cabinet and several horns splayed to provide optimum coverage. Some companies went as far as five or six-way active systems.
"Back on the high-frequency side of things, in the early days, the JBL 2482 4-inch compression driver was very popular. This had a phenolic diaphragm so it would go down to 250-300Hz and people used it as a combined high mid and high frequency driver. Nowadays, you find very few compression loaded mid devices."
PW: When it came to setting up these systems, how much was based on acoustic principles and how much was guesswork?
BW: It was really hit and miss! The information that was available then was pretty limited, so the emphasis was on having an efficient system that was quick to set up. There were one or two people who had probably spent an hour or two with the likes of Steven Court or Dave Martin who had an idea of what they were doing, but most were pretty uninformed."
GH: "But you do have to remember that this is such a tiny industry, and even today, there are probably fewer than a couple of dozen companies building finished PA systems. The R&D budget doesn't run to millions, and most of the progress was due to people like Dave Martin and Tony Andrews, working in their garages, trying out new ideas."
BW: "At Entec, we were involved for a long time with festivals, and if we were to look back now at how we used to stack the systems in those early days, we'd be horrified. But gradually, over the years, we learnt how most efficiently to stack the PA and that stands up even today."
PW: I've always been worried by the old systems, where multiple high-frequency horns were banked with overlapping directivity patterns; the interference between them must have been horrendous. Current systems appear to work on the basis of carefully controlled directivity, allowing them to be mounted in an array to give much more predictable results."
GH: "Indeed — the next logical step was away from a fully modular PA system to a number of full-range cabinets or two-pack systems where one box handles the bass and the other box covers the mid/high portion of the spectrum. The pioneers of this approach were probably Turbosound, followed closely by Dave Martin's RS1200. The RS1200 sounded great but was very heavy. Once these systems were established, they paved the way for arrayed loudspeaker systems, but along the way, driver technology continued to progress. For example, JBL switched from aluminium to titanium diaphragms in their pressure drivers, which gave a much longer lifespan. Of course this brought up further areas of debate, such as does aluminium sound better than titanium, which is probably true. Titanium gives a slightly harder edge to the sound, but when you're out on the road, it's more important that the diaphragms live for the whole of the concert!"
PW: Talking of drivers, I've always assumed that efficiency has to be traded off against overall sound quality. For example, highly damped loudspeakers are capable of very low distortion figures, but at the expense of efficiency. Is this still true? Or to put it another way, how closely can a modern PA system approach a big hi-fi system?
GH: "It depends on the type. The Stage Accompany system really is a big hi-fi, and you'll probably find the people who have used it would agree that it is superb for use in small venues, but that it wouldn't be great for doing Wembley stadium. Efficiency is the trade-off, and if you need to get a lot of sound into a large area, then you need high efficiency. That will invariably be at the expense of some aspect of the sound quality."
BW: "I feel we should mention how American and British/European systems started to differ. The Americans have a lot of huge stadia, and tended to go towards direct radiating loudspeaker enclosures with sub-woofers which would produce a really full-bandwidth sound. The Europeans went with horn-loaded boxes, where the bass response has to be rolled off below the cutoff point of the horn, which meant, to some extent, that there's a limited bandwidth. Whenever people go over from Europe to America and vice versa, they notice a significant difference between the types of system, which can be a problem."
PW: When did people take their PA systems off the floor and start flying them above the stage?
GH: "There has always been a desire to fly systems, it's more a case of the technology being available to do it."
BW: "If you were to look at Hammersmith Odeon, which was one of the major rock venues, you didn't have the room to stack a PA left and right — you also needed to provide coverage for the balconies, and you had to maintain sight lines. To solve the problem, scaffolding was built at each side of the stage, and we'd have to carry heavy cabinets such as Martin bins up this scaffolding. The next stage was when some of the rigging companies came out with platforms so you could load the gear onto the platform and fly the entire thing. Eventually, it got to the stage where a lot of the systems were flyable."
PW: How much did this influence the physical design of systems — because there's an obvious advantage in having the lightest possible cabinets if you're going to suspend them in some way?
BW: "That was a natural progression, but also trucking costs could be reduced if systems could be made lighter. The TMS3 was a great advance in this respect. Cabinets and mixers are designed to pack into standard trucks, but problems still arise in international touring, where trucks are of different widths."
GH: "It must have been in the 70s, when US and UK companies went in different directions, and whereas most of the UK companies — with the exception of Tasco — were using Martin or Turbo, the American companies tended to build their own system, so we had the likes of Clair Brothers with their S4 system, Electrotek with the Lab Q, and Showco with the Prism. The beauty of that was that their systems were unique, so if they could attract a client, they could hang onto them — if the client liked the system, they were almost duty bound to stay with the company. You didn't see much of that in the UK with the possible exception of Tasco — everyone else was using off-the-shelf products."
PW: Returning to the logistics of flown systems, is it common practice to keep the sub-bass speakers on the ground or are these flown too?
GH: "Subwoofers tend to sit on the floor because you get better acoustic coupling that way. However, most people who produce a flying system offer some form of flying sub-bass module designed to cover the front section of the audience or for use on delay towers. "
PW: Is the increased acoustic coupling provided by floors and walls exploited to make bass systems more efficient?
GH: "Ideally, you'd shove all your low bass speakers in a corner because that gives the best possible acoustic coupling into the room, but it's seldom done in practice because there tend to be awkward things like musicians and stages in the way. Bass is the one thing you can't predict, and we know this more from installation work than from touring; you can plan out exactly what your mid and high frequency coverage is going to be in a given room, but you just can't do that with bass.
"There is an exact parallel with radio transmitters; I spoke to a guy from the BBC once, and he told me that with FM, you can stick a transmitter on top of a hill and map out very exactly what the reception area will be. With long wave transmitters, they stick them in a valley, hope for the best, and then measure the result afterwards! It's the same with sound — the longer the wavelength, the harder it is to predict the outcome."
Next month, we'll be talking to Guy and Bruno about more aspects of live PA use, including foldback monitoring, effects use and sound levels. We'll also be finding out how they see PA developing in the future.