The modular touring machine

The 1980s turned custom rigs into repeatable boxes. Clair’s S-4FClair BrothersS-4F1974 (S-4); 1982 (Series II / S-4F)The Clair S-4, designed by Gene Clair with Stan Shaak, was Clair's first all-in-one four-way box, debuting in January 1974 in Japan and Hong Kong. It held two 18-inch bass drivers, four 10-inch mids and HF and super-HF horns in a roughly 420-pound cabinet sized two-wide for a US trailer. The 1982 Series II (S-4F) added a composite back and aluminium corners for rigging.Open profile → and R-4, Turbosound’s TMS-3TurbosoundTMS-3c. 1981Turbosound grew out of Tony Andrews's 1973 [[festival-group-pa|Festival System]]. Its TMS-3 three-way enclosure used the patented TurboMid device, and Turbosound describes it as having become 'the most copied system in the industry'.Open profile →, and Martin Audio’s PhilishaveMartin AudioPhilishave systemMid-1970sDave Martin founded Martin Audio in 1971 after seeing RCA W-bin cinema cabinets on Iron Butterfly's tour. His MH212 midrange horn, nicknamed 'Philishave' after the electric shaver it resembled, is credited by Martin Audio with starting the shift to dedicated horn-loaded midrange sections.Open profile → and Modular 2Martin AudioModular 2 system1970sMartin Audio's modular package combined folded-horn bass bins with an MH212 [[martin-philishave|Philishave]] midrange horn and an HF2M treble horn per side, typically through a three-way crossover around 250 Hz and 1.5 kHz. It scaled by adding more bins and horns.Open profile → systems combined horn-loaded mids with compression-driver highs in cabinets that could be stacked or flown by the dozen. EAW’s KF850EAWKF8501988The KF850, designed by Kenton Forsythe, combined a horn-loaded 15-inch woofer, a horn-loaded 10-inch midrange and a 2-inch compression driver on a 55°×40° horn in a trapezoidal cabinet. EAW called arrays of them a 'Virtual Array', curving matched boxes for even horizontal coverage.Open profile → and BH882EAWBH882 bass horn1980s–1990sThe EAW BH882 is a folded-horn bass cabinet loading two 18-inch woofers for maximum efficiency, with an optional mouth extension. EAW marketed it for dance clubs and large installations.Open profile → brought the approach to rental fleets worldwide.

Clair Brothers S-4F© Clair Global / CLAIR Used Gear · © Clair Global; used for identification and historical commentaryTurbosound TMS-3© Warehouse Sound Services · © Warehouse Sound Services, used for identification and historical commentaryMartin Audio Philishave system© Martin Audio · © Martin Audio; used for identification and historical commentaryMartin Audio Modular 2 system© Martin Audio · © Martin Audio; used for identification and historical commentaryEAW KF850Kurt Snieckus · CC BY-SA 2.0EAW BH882 bass horn© Eastern Acoustic Works · © Eastern Acoustic Works; used for identification and historical commentary

Huey Lewis and the News provide a detailed period example of that modular approach. David Scheirman’s June 1985 R-e/p report describes Sound On Stage supplying the band with its Power Physics system beginning in mid-1984. Company co-owner Jerry Pfeffer and engineer Chris Lovett developed an integrated touring package around trapezoidal, horn-loaded enclosures. Five basic cabinet types combined the CS-15 bass enclosure, with a Gauss 15-inch Model 5642 driver, a mid-bass enclosure with two JBL 10-inch K110s, and three alternative mid/high boxes: Twin, Shin and Hurler. Different horn configurations let the crew adapt coverage to each arena rather than treating every cabinet as interchangeable.

The Power Physics rig was engineered around the journey from truck to roof. Five-box stacks travelled strapped to dollies; individual cabinets had permanent wheels and an integral handle. Adjoining metal frames were bolted together, with steel safety cables and ratchet straps securing the assembly. Scheirman describes a five-stack array weighing approximately 4,000 pounds and, at the arena show he observed, a total of 102 cabinets divided between flown main clusters, rear fills, sidefills and ground-supported deck stacks. Figure 7, reproduced below from the article, records the stage layout and chain-motor pickup points. It is the original not-to-scale period drawing—not a modern reconstruction or a rigging specification for use today.

The same report shows how much of the system existed beyond the loudspeakers. Crest amplifiers powered separate frequency bands, and an Uptown Audio CO-4C four-way electronic crossover drove the Power Physics system, with a Brooke-Siren FDS-340 held as standby. Lovett describes moving from earlier three-pole Bessel filter experiments toward examining four-pole Linkwitz–Riley filters; the article does not establish that the touring crossover had already adopted the latter. Mark Deadman mixed the house sound on a Gamble desk, while Jim ‘Bugsy’ Moran used a Gamble SC 32-16 for eight monitor mixes, adding two more when the Tower of Power horn section joined the tour. A custom vocal wedge and hanging Meyer UM-1 UltraMonitors supported the stage. Deadman’s contemporary account stresses consistent sound and an affordable touring package: carrying more loudspeakers also meant another truck. Scheirman liked the show’s clarity and coverage but wanted more system headroom, making the report a useful record of both the package’s strengths and its practical limits.

Meyer Sound tied each loudspeaker to its own processor, so the MSL-3Meyer SoundMSL-31981The MSL-3 was a smaller 'slice' of Meyer's MSL-10, with two 12-inch woofers in a horn-loaded vented cabinet and a 2-inch-throat compression driver on a 70-degree horn. Its size made it far more flexible to array.Open profile →, USW-1Meyer SoundUSW-1 subwoofer1980sThe USW-1 is a compact passive subwoofer extending Meyer systems down to 40 Hz, with two 15-inch long-excursion drivers in a braced 5-cubic-foot vented birch cabinet.Open profile → subwoofer and UM-1 wedge behaved predictably wherever they were hung. That approach made measurement-based tuning practical, and it pointed straight at the self-powered and line-array systems of the next decade. Electro-Voice’s HR9040Electro-VoiceHR9040 constant-directivity horn1975–1976A large-format constant-directivity horn developed from Don Keele's mid-1970s horn research.Open profile → constant-directivity horn and MT-4Electro-VoiceMT-4 manifold system1987The Electro-Voice MT-4 was a two-box, four-way system using Manifold Technology, which combined several compression drivers or woofers onto one horn through a manifold rather than a lossy Y-adapter. EV advertised it as a quarter the size, or four times as loud, as comparable designs.Open profile → manifold pursued the same predictability through acoustic design. The constant-directivity horn came from D. B. ‘Don’ Keele Jr.’s horn research; Keele later received a 2002 Academy Award for Technical Achievement for constant-directivity cinema loudspeaker systems.

Meyer Sound MSL-3© CUE Sale · © CUE Sale; used for equipment identification and historical commentaryMeyer Sound USW-1 subwoofer© AVGear · © AVGear; used for equipment identification and historical commentaryElectro-Voice HR9040 constant-directivity horn© Electro-Voice · © Electro-Voice; used for identification and historical commentaryElectro-Voice MT-4 manifold system© Electro-Voice · © Electro-Voice; used for identification and historical commentary

Bigger systems needed more amplifier channels and more console inputs. The Crown Macro-TechCrownMacro-Tech amplifierLate 1980sCrown's Macro-Tech amplifiers used Crown's patented Grounded Bridge output topology for large voltage swings without stacking output transistors in series. Later models such as the MA-5002VZ added a variable-impedance (VZ) power supply. Crown marked the line's run with 2008 anniversary editions.Open profile →, Crest 8001 and Lab Gruppen LAB 2000Lab GruppenLAB 2000 amplifier1980s–1990sLab Gruppen credits the LAB 2000 as the first amplifier with its patented Class TD output topology, combining Class B sound with Class D efficiency.Open profile → supplied racks of reliable power. At front of house, the 1974 Yamaha PM1000YamahaPM1000 console1974The Yamaha PM1000 was a modular four-bus console introduced in 1974, developed from a mixer Yamaha built for Japan's first outdoor rock concert, 8.8 Rockday. It had transformer-isolated inputs and outputs, four bus and four matrix outputs, and 16, 24 or 32 channels.Open profile → led to the late-1970s PM2000YamahaPM2000 consoleLate 1970sThe Yamaha PM2000 expanded the PM1000 concept into a modular mixing system with separate input, master, foldback/phone, effects-return and talkback modules, plus a mix matrix. Its operating manual treats concert reinforcement, stage monitoring, television, theatre and recording as distinct applications, showing how the same desk had to serve increasingly specialised productions.Open profile → and 1985 PM3000YamahaPM3000 console1985The Yamaha PM3000, introduced in 1985, succeeded the PM2000 with VCA and mute grouping and balanced I/O throughout, documented in detail in Yamaha's operating and service manuals.Open profile →. The Midas PRO40MidasPRO40 consoleEarly 1980sThe PRO40 (PR40) succeeded Midas's 1970s PR Series as its flagship, built from plug-in input, output and auxiliary modules so much larger custom consoles could be assembled. After Midas was wound up in December 1987, Klark Teknik completed the last units, including a 24-aux monitor console for Concert Sound.Open profile →, modular Soundcraft Series 800 and Series 4SoundcraftSeries 4 console1990sThe Soundcraft Series FOUR was a compact front-of-house console in four frame sizes from 24 to 48 mono inputs, carrying over the layout of the larger Series FIVE and adding a matrix, eight VCA groups and eight mute groups.Open profile → offered other ways to organise increasingly large shows. More groups, aux sends and matrices meant separate control of instrument sections, monitors, effects returns and different PA zones—not merely more microphone sockets.

Crown Macro-Tech amplifier© Crown International · © Crown International; used for identification and historical commentaryLab Gruppen LAB 2000 amplifier© Lab.gruppen · © Lab.gruppen; used for identification and historical commentaryYamaha PM1000 console© Yamaha Corporation · © Yamaha Corporation; used for identification and historical commentaryYamaha PM2000 console© Yamaha Corporation · Manufacturer manual cover reproduced for historical identification and commentary (fair use)Yamaha PM3000 console© Yamaha Corporation · © Yamaha Corporation; used for identification and historical commentaryMidas PRO40 console© Theatrecrafts Backstage Heritage Collection; photographer unrecorded · Archival photograph; used for equipment identification and historical commentarySoundcraft Series 4 console© Soundcraft / HARMAN International · © Soundcraft / HARMAN International; used for identification and historical commentary

The analogue console was only the centre of a much larger control position. dbx 160dbx160 compressor/limiter1976The dbx 160 of 1976 was David Blackmer's first professional compressor, built on his Blackmer gain-cell VCA with true-RMS detection and feed-forward gain reduction. A single-channel half-rack unit, it could be linked for stereo.Open profile → compressors occupied inserts; other rack channels supplied gates, equalisation and effects. Reverb and delay units usually received aux sends and returned to console channels, so the engineer mixed the effect as well as the dry signal. Every additional processor meant rack space, power, patching and another set of settings to document. Digital rack effects already offered programmable presets before digital consoles arrived; the later revolution was integrating processing and its recall into the whole mix, not inventing digital reverb.

dbx 160 compressor/limiter© Published by Mix/Mixonline; photographer and original rights holder not credited · Copyright retained by the original rights holder; reproduced for identification and historical commentary (fair use). Reuse permission not established.

The racks that hardware lived in were standardized long before touring adopted them. The 19-inch rack width with 1.75-inch unit spacing — 44.45 millimetres per U — traces to AT&T’s engineering redesign of telephone central-office racks around 1922, from which the format spread informally through telephony, broadcasting and electronics for roughly three decades. Formal standardisation lagged practice: the Electronic Industries Association’s first rack-and-panel standard appeared as C83.9-1956, was reissued as RS-310 in May 1965, and continues in the EIA-310 lineage. Why 19 inches exactly was never documented by AT&T itself; EDN’s retrospective on the rack calls the rationale folklore. Touring sound adopted the format wholesale — amplifier racks, processor racks and flight-cased shock racks — because any manufacturer’s gear then bolted into any company’s cases and rack spaces could be planned before the truck was packed.

Rigging evolved alongside the cabinets. Scaffold towers and ground stacks gave early concert crews elevated support, but modular touring truss made an overhead structure easier to transport and reassemble. Behind the Curtain's touring-history account traces a ground-supported, pre-rigged lighting truss to the Rolling Stones' 1972 tour and describes the subsequent move toward trusses flown on chain motors. That is a production-structure history, not proof that the first touring truss carried a PA. Sound crews subsequently benefited from the same overhead infrastructure, alongside purpose-designed cabinet flying hardware.

Electric chain motors supplied a repeatable way to raise and position loads: they lifted the truss or speaker assembly, rather than making an otherwise unsuitable support safe. The CM Lodestar was an industrial electric chain hoist with a 1955 product brochure; its later entertainment adoption must not be mistaken for a 1955 concert-rigging debut. Raising a cluster could clear floor space, improve sightlines and put direct sound above the front rows. The new responsibilities were equally important: roof capacity, all loads in the suspension path, inspection, motor control and qualified rigging. Scaffolding did not disappear; towers, ground-supported roofs and flown structures continued to coexist.

Powering these systems became its own engineering problem. Early rigs simply plugged into venue outlets, but as systems drew tens of thousands of watts, touring practice settled into a chain described in ProSoundWeb’s power-distribution series: a building “company switch” — or a towed generator where no adequate service existed — feeds heavy single-conductor feeder cable into a portable power distribution unit, which divides three-phase or split-single-phase supply into protected branch circuits for amplifiers, consoles and battery chargers. Generator sizing became a touring skill; FOH Online’s guidance on generator practice stresses headroom above the connected load, because an undersized or poorly regulated generator sags audibly when bass hits. Speaker-level connection also standardised: Neutrik’s 1987 speakON locking loudspeaker connector, developed partly in response to Europe’s Low Voltage Directive requirement for protection against contact with live parts, displaced bare wire and 1/4-inch jacks on amplifier outputs.

Monitoring became its own specialty. Wedges, sidefills and dedicated consoles gave each performer a mix. Wireless systems such as the Schaffer-Vega Diversity SystemKen Schaffer / VegaSchaffer-Vega Diversity System1976–1977A diversity wireless system developed for the reliability demands of major concert touring.Open profile → and Vega Cordless Mike freed performers from cables, and high stage volume pushed the industry toward in-ear monitoring.

Ken Schaffer / Vega Schaffer-Vega Diversity SystemSoloDallas · CC BY-SA 3.0

A. J. Berkhout of Delft University of Technology published the theory of wave field synthesis in the Journal of the AES in December 1988. Fraunhofer’s IOSONO system (2004) and HOLOPLOT’s matrix arrays build on it.

Kennedy's FOH survey describes the mid-1980s as the arrival of the factory touring box. Apogee Sound's 1985 AE-5, designed by Ken DeLoria, was a processor-driven bi-amped trapezoid with a 12-inch woofer and ferrofluid-treated HF driver; JBL's 1985 Concert Series, including the 4850JBL4850 concert system1985–1986The JBL 4850 was the base model of JBL's Concert Series, its first line of pre-wired, pre-tested trapezoidal touring boxes. It paired two 12-inch 2204H woofers with a 2445J compression driver on a Bi-Radial horn in a fibreglass-coated plywood cabinet with a 45-degree wedge shape and eight rigging points.Open profile →, was its first factory-packaged touring trapezoid and rack line, meant to replace home-built shop boxes; and EAW's KF-850EAWKF8501988The KF850, designed by Kenton Forsythe, combined a horn-loaded 15-inch woofer, a horn-loaded 10-inch midrange and a 2-inch compression driver on a 55°×40° horn in a trapezoidal cabinet. EAW called arrays of them a 'Virtual Array', curving matched boxes for even horizontal coverage.Open profile →, also 1985, became the standard one-box rider requirement. Kennedy also credits Renkus-Heinz's 1989 CoEntrant horn with combining a midrange cone and HF compression driver on one concentric throat.

JBL 4850 concert system© JBL Professional · © JBL Professional; used for identification and historical commentaryEAW KF850Kurt Snieckus · CC BY-SA 2.0