Welcome back to our chronology of the history of P.A. Loudspeakers. As we noted in last month’s overview of P.A. in the 1970s, rock concerts and festivals rapidly expanded during this decade, driving demand for high-performance sound systems and writing a new chapter in the history of high-output live-sound systems. With Part 3, we resume our look at year-by-year P.A. developments.
1970 — Bob Heil and Heil Sound create a large and innovative 4-way sound system for The Grateful Dead. Powered by home Hi-Fi amps, it was estimated to be close to 20,000 watts in total power (Fig. 1). It was deployed for the band’s performances at the Fox Theater in St. Louis in late 1971. The Dead’s sound engineer, Owsley “Bear” Stanley, was incarcerated at the time.
1970 — Roy and Gene Clair switch to more robust JBL drivers in their loudspeaker designs. Clair Brothers’ new “slant monitors” — angled stage wedges — toured with Blood, Sweat & Tears, and by 1971, Clair began hanging speakers for Elvis Presley using a special aluminum frame (Fig. 2). It was a 2-way, 360-degree mono cluster with amp rack in the middle.
1970 — The Isle of Wight Festival, launched in 1968, shattered records by 1970 with its third and final event before a long hiatus, drawing close to 600,000 to southern England. Rikki Farr, who played a key role at the event, would go on to launch a variety of audio companies including LA-based Electrotec.
1970 — Altec Lansing’s Don Davis hires Mark Engebretson as a Midwest field rep. (Engebretson would go on to create audio innovations for JBL, Stanal Sound, A-1 Audio, QSC and others, accepting the Parnelli Audio Innovator award in 2013).
1970 — The Turbosound story unofficially begins. Not yet called Turbosound, the company would become known for audio innovations including the first Turbo phase-plug mid-bass device, used with 12” drivers, in 1973.
1970 — Iron Butterfly tours the UK with a bin-and-horn speaker system credited to Bill Kelsey and Jim Morris (Kelsey-Morris). The horn-loaded loudspeakers’ lower-frequencies were handled by the original RCA W-Bin. It then became apparent that a clearer midrange could be achieved if the bass and midrange were split out to three specialized drivers and horns in a 3-way system.
1970 — JBL introduces its 2440 variant of the earlier 375 HF (high-frequency) horn compression driver, with a 4” voice coil. It proved to have significant power handling advantages over Altec-Lansing and Electro-Voice drivers (which had 2.8-inch to 3-inch aluminum diaphragms). The JBL 4” voice-coil woofers also featured ruggedized suspensions and cones, to hold up better during loud rock concerts. JBL VP/historian Mark Gander noted that high strength epoxy adhesives and Kapton coil formers gave JBL’s drivers a competitive edge. The more rugged JBL phenolic diaphragm 4” voice-coil mid-high compression drivers became very popular for the highest-SPL concert sound applications (typically used with additional tweeters).
1970 — Showco is founded in Dallas by Jack Maxson, Rusty Brutsche and Jack Calmes to provide high performing concert sound and lighting systems in the post-Woodstock era. The company supported shows for Led Zeppelin, Three Dog Night, James Taylor and Elvis Presley.
1971 — Showco builds a 2-way sound system for Elvis Presley (Fig. 3). The bass cabinets have four 15” speakers.
1971 — McCune Sound Service’s Harry McCune, Jr. turns to John Meyer and Bob Cavin to come up with a three-way loudspeaker that would match the Altec 604’s sound quality but be much louder in volume, while also being compact enough to ship as jet cargo. The result, the JM-3 integrated concert loudspeaker, was named with John Meyer’s initials. It was powered by a McCune tri-amped rack concealing three different Crown amplifiers and active-unique EQ/XO electronics.
1971 — Joel Silverman and Ross Ritto launch Silverfish Audio in Rochester, NY, focusing on touring sound reinforcement. By 1976, Silverfish had Jimmy Buffett as a client, and by 1978, Silverfish opened a shop in southern California. (Dave Shadoan teamed up with Ritto, formally changing the company’s name to Sound Image in 1982).
1971 — Dave Martin starts up Martin Audio in London. His innovations included the horn-loaded bass cabinet principle.
1971 — DAS Audio is founded in Valencia, Spain by Juan Alberola. He began by designing and manufacturing his own loudspeakers and components, provided larger loudspeakers for Spain’s thriving dance club scene. The company later expanded internationally.
1972 — Electro-Voice is the first to include Thiele-Small parameters on woofer specification sheets, for user modeling of enclosure characteristics, predicting maximum output and low-frequency response.
1972 — Psychoacoustics expert Amar Bose, an MIT professor for 45+ years, fulfills his vision to situate Bose’s headquarters atop The Mountain in Framingham, MA. The company launched the Bose 800 Professional Speaker after pro users started repurposing the 1968 Bose 901 home speakers as compact PA speakers.
1972 — Explo 72 draws Christian students to the Cotton Bowl and other Dallas area venues from June 12-17. More than 150,000 gather on the last day on open grounds for an eight-hour event featuring the Rev. Billy Graham and Christian acts along with Johnny Cash and Kris Kristofferson. The event is cited as an important milestone in the emergence of the Contemporary Christian music genre. Showco supported the event’s sound reinforcement needs.
1972 — Al Siniscal presents a 10-page technical paper, High-Intensity, Modular Tri- & Quad-Amplification Loudspeaker Systems, at two AES conventions, in Munich, Germany and in Los Angeles. The founder of A1 Audio in Las Vegas, he had spent several years as the sound designer for headliners at Caesars Palace. Along with his early powered loudspeaker designs, which were multi-amped, he used injected foam to dampen horns and eliminate ringing. (Siniscal received the Parnelli Audio Innovator award in 2010.)
1972 — Dinky Dawson’s high-fidelity Acoustic Suspension Music Reproduction system, described as inspiring elements of the Dead’s Wall of Sound (1973), makes its debut.
1972 — The fifth edition of Loudspeakers by G.A. Briggs is published by Rank Wharfedale Ltd., Bradford, UK. Along with the latest advances in materials, measurement techniques and design principles, it served as a retrospective of decades of loudspeaker developments.
1972 — Mike Klasco, a recent NYU graduate, founds General Linear Instruments (GLI). (In 1983, he moved to California and founded Menlo Scientific. He published over 500 articles in technical journals and has a dozen patents.)
The Sound Loudness Wars Begin
1972 — Deep Purple set the record for loudest band during a show at the Rainbow Theater. The show, which peaked at 117 decibels, “was so loud that it knocked three people unconscious.” Years later, in Sweden, the band’s promoter was fined when their show reached 102 decibels — an illegal volume level. Singer Ian Gillan later said in an interview that their focus was no longer on loudness.
1973 — Mike Adams joins Silverfish Audio, working as a sound designer and audio engineer. He later led Sound Image’s Audio Composite Engineering/ACE division.
1973 — DB Keele of Electro-Voice develops constant directivity (CD) horn technology, promising better control of high-frequency dispersion. EV also publishes full sets of third-octave polar responses for horns. (More details: FOH, May 2025, page 36).
1973 — The Grateful Dead perform with The Wall of Sound, a massive and unique concert sound reinforcement system, starting in March 1973. The largest concert sound system built in its day, the Wall of Sound fulfilled lead designer Owsley “Bear” Stanley’s desire for a distortion-free sound system that could also serve as a stage monitoring system. Due to its size, weight and resulting expense, the full system was only used until Oct. 1974. (More details in a future issue of FRONT of HOUSE).
1973 — Don and Carolyn Davis found Synergetic Audio Concepts (SynAudCon) to meet the growing need for training in the live-sound industry. They published the first edition of the authoritative text, Sound System Engineering, the same year. (For the next 23 years, SynAudCon collaborated with pro audio veterans to train more than 10,000 industry newcomers.
1974 —Gene Clair and his cousin Stan Shaak develop the S-4 all-in-one concert loudspeaker (similiar to the newer model shown in Fig 4). This 4-way, 405-lb. loudspeaker system included two 18-inch woofers, four 10-inch mid-range speakers, two 2-inch throat high-frequency drivers and horns, and two ultra-high frequency ring radiator drivers. The cone drivers were vertically aligned so they would couple with adjacent cabinets in line arrays.
1974 — Keny Whitright designed Showco’s M4 4-way full-range loudspeaker cabinet. “It was used for flown stage monitors and front and rear fill cabinets,” noted Rusty Brutsche. (Fig 5). “The woofers were JBL K120. The mid-range drivers were JBL 2480, one on each JBL horn, and high frequency drivers were JBL 075 ring radiators,” he added. (Whitright received the Parnelli Audio Innovator Award in 2023).
1974 — Electrosound is founded in London. The company expanded to Hollywood in 1978, and after buying TFA Lighting from Tom Fields in Boston, it became TFA Electrosound. A challenge by U.S.-based Electrosound Inc. led the company to change its name to Electrotec.
1974 — Cliff A. Henricksen, a musician, audio engineer and MIT-educated scientist, begins his career in pro audio by starting a research group at Altec Lansing in Anaheim, CA.
1974 — Harman acquires Tannoy, and Tannoy founder Guy R. Fountain retires. (Tannoy later merged with Goodmans, forming TGI, then became part of TC Group in 2002 and Music Group, now Music Tribe, in 2015.)
1974 — CSNY perform at Oakland Coliseum during their reunion tour. Cal Perkins designed the massive FM Productions system for this event, promoted by Bill Graham (Fig. 6). The fully horn-loaded loudspeakers had JBL drivers and HF horns. JBL 4550 and 4560 bass horns (Perkins Bass Bins) also played a role.
1974 — Jonas Renkus, a former director at Altec Lansing, founds Emilar speakers. They were noteworthy for their high-frequency compression drivers with aluminum diaphragms, designed with an elastomer surround to address problems from legacy aluminum diaphragm failures related to surround cracking.
1975 — Bart N. Locanthi is named a VP of Pioneer North America (after leadership roles at Altec Lansing and JBL). While at Pioneer, he and his team designed a new class of state-of-the-art TAD loudspeaker HF compression drivers with Beryllium diaphragms and more advanced phasing plugs. (Fig. 7).
1975 — Pink Floyd purchased a building in London at 35 Britannia Row. In 1976, Britannia Row Productions provided sound for Queen and 150,000 fans at Hyde Park. In 1977, they supported Pink Floyd’s global Animals tour, followed by tours for Bob Dylan, Eric Clapton, Peter Gabriel, The Cure and others.
Mid 1970s — Malcolm Hill’s massive Hill PA Systems made their debut in the UK, combining the solid-state amplifiers Hill had developed years earlier with mixing consoles and their loudspeakers using various drivers from the UK and USA.
1976 — Ed Long develops a passive crossover for loudspeakers that aligns the band-passes in time, trademarking it as Time Alignment. It remained influential in loudspeaker design through the 1980s. Long and Ronald J. Wickersham patented a method for extending LF response that was licensed by Bag End for their ELF subs.
1976 — Mark R. Gander joins JBL, launching a 40-plus year career that included roles in design and leadership. He also provided critical tech support for several leading tour companies’ loudspeaker system designs (Fig. 8). Here, he is pictured next to the first generation JBL Cabaret series he developed and marketed in 1979. The series was credited as being the first full line of portable PA systems for the MI market.
1976 —The Who play in London at the Valley stadium, and the Tasco 76,000-watt system powered by 80 Crown and 20 Phase Linear amps helps the concert earn a spot in the 1987 Guinness Book of World Records as the loudest concert, measured at 126 dB 100’ from the loudspeakers. “I’ve always been embarrassed by that,” said Nick Blyth of Tasco.
1976 — Denis Lefrançois gets assigned to handle all the audio for the Montreal Olympics. Audio Analysts provides the S-4, licensed from Clair, for event rental clients.
1977 — Solotech is co-founded by Denis Lefrançois and André Riendeau. In just one year they triple their revenues and quickly begin a series of acquisitions and expansions.
1977 — Ed Wijnker, sound engineer for Dizzy Man’s Band, founds Stage Accompany (SA) in the Netherlands. SA would go on to collaborate with Philips on the SA8535 Ribbon Compact Driver, building on their earlier SA8526 in 1990 and the SA8525 in 1987.
1977 — McCune Sound turns to John Meyer to develop the JM-10, the first large-format high-output all-in-one 3-way stadium concert array (Fig. 9). The JM-10’s patented low-distortion compression diaphragm treatment made its 1977 debut on the Kool Jazz Stadium Tour.
1978 — Turbosound is formed by Tony Andrews, Tim Isaac and sound engineer John Newsham.
1977 — Martin Audio’s MH212 “Philishave” adds to the mid-range horn trend. Martin’s patented 4-way concert loudspeaker systems would serve as a lasting legacy for company founder Dave Martin, who died in 1992 (Fig. 10).
1978 — Community offers The Cluster Computer. While relatively basic, it was among the first loudspeaker coverage simulation tools to be made available.
1978 — Kenton Forsythe and Kenneth Berger co-found Eastern Acoustic Works (EAW). They had worked together at Forsythe Audio Systems and, the same year, developed the Forsythe SR-109, an innovative mid-bass horn that incorporated a cone driver with integrated phase plug.
1978 — Don Pearson and Howard Danchik co-found Ultra Sound. (They supported the Grateful Dead and other bands for many years, eventually replacing the Wall of Sound with Meyer Sound loudspeaker systems.)
1978 — Altec Lansing’s Cliff Henricksen and Mark Ureda publish a JAES article on Manta-Ray Horns, advancing early constant directivity loudspeaker design. (Henricksen would go on to play key roles developing advanced HF and mid-bass horns and PA loudspeaker systems for Community, Electro-Voice, US Sound, Bose Corp. and Ocean Way Audio. Ureda, who also spent 25 years in the aerospace industry, did loudspeaker design and management for JBL and Harman and has also served in advisory roles at Biamp, Mackie/LOUD Audio and Bose Professional.)
1979 — John and Helen Meyer establish Meyer Sound. The company launches the UM-1 UltraMonitor, which featured a patented horn design credited for dramatically reducing distortion (More details to come in Part 4).
1979 — Harro K. Heinz and Algis Renkus launch Renkus-Heinz. (Algis Renkus’ father, Jonas A. Renkus, who had worked at Altec Lansing under John Kenneth Hilliard, would later join the company).
1979 — Raimondo Sbarbati founds SICA (Società Italiana Costruttori Altoparlanti), an Italian manufacturer of transducers.
1979 — Tom McCauley establishes McCauley Sound in Puyallup, WA. The company, like most, shifted from making drivers to complete loudspeaker systems.
Late 1970s — Tasco grew to became one of the largest concert sound companies worldwide. The Tasco “Harwell” loudspeaker system was a significant advancement over Tasco’s earlier “stacked-up piles of components.”
Late 1970s — Don Puryear and Lynn Gonyea buy Tycobrahe Sound Company from Bob Bogdanovich, renaming it Innovative Audio. A few years later it was sold again, becoming Schubert Systems Group. (See Cal Jam sidebar).
Late 1970s — Northwest Sound supports Neil Young’s 1978 Rust Never Sleeps tour with loudspeaker arrays using JBL drivers (Fig. 11). Cal Perkins joined Bob Sterne’s Northwest Sound team and designed a series of high-fidelity 2-way horn loudspeaker systems plus subwoofers. The company made a large investment in TAD HF drivers and incorporated them into the loudspeaker arrays deployed for The Long Run tour by The Eagles in 1979.
In Part 4 we will finally see how the concert touring PA factories (as we know them now) would catch onto the concert touring PA trend, providing higher-output and ruggedized 3- to 4-way loudspeakers with compact vented subs.
A Tale of Two Cal Jams: Record-Setting PA Loudspeaker Systems
The California Jam festivals of the 1970s — Cal Jam in 1974 and Cal Jam II in 1978 — were landmark rock events, drawing 250,000 and 350,000 paying music fans, respectively. Each event also marked major audio breakthroughs and refinements that improved the concertgoers’ listening experience while enhancing the productions’ efficiency and the festivals’ professionalism and profitability.
The first Cal Jam, held at the Ontario Motor Speedway on April 6, 1974, set new records for music festival ticket sales while also providing the largest and loudest concert sound system to date. Deep Purple, Black Oak Arkansas, Black Sabbath, Earth Wind and Fire and Rare Earth each contributed their touring PA systems with 3-way Tycobrahe loudspeakers, adding to the massive festival PA system. Sixteen-foot bass horns from Phoenix Sound and a large array of bass scoop horns from Flag Systems (plus delay towers) overlapped bass frequencies from the full-range 3-way Tycobrahe main loudspeakers. The system, powered by Tycobrahe BFA-2000 amplifiers, added up to 54,000 watts RMS in total audio power.
Along with its record-breaking power, the system was noted as one of the first to stack loudspeaker cabinets in large columns (to focus the sound onto the audience). Another innovation was setting up stage sets for each band on rails, streamlining band changeovers, and the creative use of audio delay towers and zone-based amplification strategies. The touring sound system for Emerson, Lake and Palmer, which played Cal Jam 1’s final set, was set up about half a mile from the stage and timed with a tape delay to coincide with the sound from the stage.
After the original California Jam’s success, it made sense to organize a second festival. California Jam II, held on March 18, 1978 at the same site, featured the largest sound system ever deployed for a festival. The producers hired Rikki Farr’s TFA Electrosound (later Electrotec) to assemble a massive five-way horn-loaded sound system using JBL drivers for Aerosmith, Foreigner, Ted Nugent, Heart, Santana and the other bands and special guests performing. Cal Jam II ended up exceeding the original Cal Jam’s success with total attendance, ticket revenues, and concert sound system power — in this case, more than twice the total power of the Cal Jam I sound system. Mick Whelan explained how the PA deployment was made more efficient because “it was the first PA built directly into flight cases, and every PA cabinet had casters on each enclosure.”
For more on live-sound design in large spaces see David K. Kennedy’s consulting sound design website at D-K-A.com.
