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1977 Kool Jazz stage equipped with JM-3s joined by JM-10s. (Courtesy of McCune Audio Video Lighting.)

The Development Of The McCune JM-3 Loudspeaker, Part 2: Additional Components

Modifications to the JM-3 as well as later developments that include the JM-10 full-range loudspeaker along with JM-5 and JM-7 subwoofers.

Editor’s Note: Go here for part 1 of this article, “McCune & Meyer Create The JM-3 Integrated Concert Loudspeaker.”

A subwoofer, the JM-5, was designed to cover the bottom two octaves for the early JM-3. Containing four Gauss 18-inch woofers, it was a larger enclosure and could not travel as easily. Later, the JM-7 subwoofer was created in the same enclosure size as the JM-3.

But in 1976 after John Meyer returned from his electroacoustic linearity studies in Switzerland, he modified the JM-3 for greater frequency range, raising the top end to 16,000 Hz and extending the bottom to 40 Hz. At this point the lower reach of the JM-3 was enough by itself for many clients, especially for the pop vocalists which were McCune’s forte.

After his Swiss sojourn, Meyer was contracted in 1976 by McCune Sound Service General Manager Mort Feld to expand upon the JM-3 in creating the new JM-10 with a stated selling point of replacing 10 JM-3s, though in practice it replaced six, but with smoother array coupling between the high drivers. Company owner Harry McCune, Jr. was against the expensive project, but Feld went ahead anyway, starting the venture while Harry McCune was out touring.

Meyer and the McCune engineering team designed the JM-10 concert array to be ready by 1977. Meyer and chief engineer Bob Cavin arrived at an analog bucket-brigade solution for the nagging high frequency time alignment problem. The bucket brigade was preferred for its low distortion, but it was hissy at idle, so Cavin put a fast-open, slow-release gate on the highs.

JM-3s outboard of JM-10s at 1977 Kool Jazz. (Courtesy of Kevin Tyrrell, McCune Anaheim.)

In addition, Meyer’s new patented low-distortion compression diaphragm treatment was incorporated into all JM Series boxes, and it also found its way into smaller front fill and stage monitor boxes that included the 2-way SM-3 of 1976 and the coaxial SM-4 of early 1977. (Meyer drilled out a central hole and four arcs of phenolic material in the compression diaphragm to free up the movement of the dome, coupling it to the horn’s throat air resistance for less distortion. See U.S. patent number 4152552.)

Meyer said of this period that McCune freely applied Meyer’s patented technology to multiple loudspeaker models despite the contract specifying only the JM-10 project. But he’d been using McCune’s resources for his research, and the line between McCune and Meyer was further blurred when John agreed to help tune the SM-3 and SM-4 enclosures simply because he was there in the shop working alongside his McCune colleagues: electronics whiz Istvan “Steve” Kadar, driver cone guru Dennis Minnick, second engineer Mike Brady and chief engineer Bob Cavin. The elder Harry McCune Sr, company founder, was often in the shop but he devoted his time to other projects. (John Meyer established Meyer Sound in the Bay Area in 1979.)

Initial Deployment

The first JM-10 gig was the Kool Jazz stadium tour of 1977. Additional JM-3s were used as out fill. Cavin accompanied the tour to provide top-level technical support on this maiden voyage of the JM-10. Unusually, the dedicated JM-10 processor/amplifier system contained an instant hot backup with a fail-over circuit to switch away from any malfunctioning amplifiers – another Cavin invention. Multicore speaker cables were terminated with military-grade hardware.

Dennis Minnick directed video for many of these shows and remembers a hurried JM-10 installation in Texas Stadium near Dallas because the truck was late from New Orleans. Natalie Cole’s nervous production people sniped at the McCune crew, saying these few boxes weren’t enough to fill the stadium. But when system tech Mike Neal opened up the main faders for a full volume test, they were awestruck. The JM-10 served for the next two decades as McCune’s largest concert system.

A McCune promotional photo from 1977 or later, with an SM-3 two-way at left, SM-4 two-way coaxial at right, and JM-3 at rear with Shure SM56 microphone. (Courtesy of Kevin Tyrrell, McCune Anaheim.)

In October 1980, the Grateful Dead concocted a monstrous loudspeaker combination inside Radio City Music Hall in Manhattan, all from the extended family of Meyer. JM-10s were used as left and right mains, the Bill Graham Presents-owned System 80 as a center cluster (designed for the Dead in collaboration with Meyer), supported in the bottom octave by Meyer Sound Labs 650 subwoofers.

The carefully tuned conglomeration measured 140 dB at 10 meters – with dangerously low levels of perceptible distortion. BGP technician Steve Neal said, “We’re very aware that the system is capable of human damage.” Since BGP and McCune gear was working side-by-side, Bill Graham’s anti-McCune vow had apparently expired. (The source of the disagreement is detailed in Part 1).

With just a few JM-10s produced, the fleet of JM-3s continued to gig heavily. Harry McCune Jr, Cavin and tech Terry Simmons flew with JM-3s to South America in 1978 for a Burt Bacharach tour. Eight JM-3s plus subwoofers were used at the Hollywood Bowl for Playboy Jazz in the late ‘70s. The same setup was used by Barry Manilow for his Summer Tour of 1978, with added JM-3 side fill monitors. Mike Neal specified JM-3s for multiple stages at the Monterey Jazz Festival for many years, and he deployed dozens of JM-3s throughout New Orleans venues for the Jazz and Heritage Festival.

At McCune’s Anaheim shop, production manager Kevin Tyrrell was surprised to see drummer/engineer Jim Mothersbaugh of Devo walk in unannounced, hoping to book the JM-3s based on rave reviews from his musician friends. Devo ended up paying more than $8,000 for a massive JM-3 rig plus JM-10s and subs for a week of rehearsals and three show dates at the end of December 1979, concluding with New Year’s Eve at Long Beach Arena. That was a busy night for McCune, also running JM-3 concert rigs for Jefferson Starship in San Francisco and the Grateful Dead in Oakland.

Around this time, a troubling problem began appearing: the weight of the mid-range compression driver could sometimes snap the throat of the fiberglass horn if the enclosure was treated roughly in transit. When this happened there was no fix, as the wooden framework was glued permanently around the mid-range horn. The affected enclosures were discarded, struck from inventory, while the good ones were opened up for examination.

A JM-10 stack and clowning employee Mike Devonair. (Courtesy of McCune Audio Video Lighting.)

The basic problem was that the heavy alnico compression driver had no support other than being bolted to the fiberglass horn, so Jim Cavin (Bob’s brother) and Mike Brady cradled it with metal and foam rubber to hold the compression driver steady against mechanical shock. Hal Soogian, Jim Cavin and Brady retrofitted the remaining 128 boxes.

The JM-3 box served as McCune’s standard festival system throughout the 1980s, many of them receiving a coat of black paint to update their appearance, as the natural wood was becoming marred by usage, and the ‘80s encouraged a black industrial look. First two, then three, and then four JM-3s perched for years atop the proscenium in the San Francisco Fairmont’s Venetian Room, first in natural wood then later covered in dark brown paint, except the unseen rear of the boxes.

This was the hotel’s nightclub where Tony Bennett regularly sang about leaving his heart in San Francisco. (A consummate professional, Bennett called out standard ISO EQ frequencies for adjustment during sound check.) JM-3s were used by McCune in fashion shows, sports arenas, political conventions, corporate events and theater work.

Next Generation

Despite its ample strengths, the JM-3 had a few technical flaws. One was that the high-frequency horns were too far forward, creating a minor amount of acoustic shadowing of the low frequencies, but more importantly, giving the enclosure two different apparent apexes (the focal point of pattern dispersion.) This meant that a horizontal splay of JM-3s did not quite live up to expectation, with slight lobing and combing anomalies heard at the junction of two boxes side-by-side – problems that did not disappear with distance. Vertical stacks arrayed nicely, though, with the top box tilted upward to hit the higher seats.

In addition, the JM-3 enclosures were built in batches as funds became available, with each batch having small variations, causing them to sound slightly different. There were also some practical flaws. As noted earlier, the JM-3 did not have true handles, making it more difficult to lift the heavy box. Finally, the wooden skids on the bottom wore down with usage, revealing metal screw heads which cut into the stage or speaker platform.

What happened to the JM-3? Approximately 130 boxes were built in total. Four prototypes were sold to A&M Studios. A few cabinets were lost or damaged in the line of duty; at least one burned because the Crown DC300 amplifier could fail to full DC rail voltage, heating the two woofers fiery red. The amplifier output stages could be fried if a faulty speaker cable lost one conductor under load.

JM-10 amp rack with automatic failover circuitry invented by Bob Cavin. (Courtesy of Kevin Tyrrell, McCune Anaheim)

But the next generation arrived in 1982 when McCune developed the powerful 2-way SM-5 loudspeaker, its own version of the Meyer Sound UPA but with substantial engineering differences. Smaller McCune crews could now be dispatched to haul around the much lighter SM-5, augmented as necessary in the lower octaves by Meyer 650R subwoofers that one person could roll into place.

The SM-5 was now picking up much of the bread-and-butter work of the JM-3. And then after another decade of shifting client tastes, the JM-3 began to look bulky and old-fashioned. Finally, line arrays were suddenly the “hot new thing” in the 2000s, and nobody wanted the old boxes.

Harry McCune, Jr. died in 1996. His son, company president Allan McCune, saw many of the JM-3 enclosures gathering dust in the warehouse and decided to revive six of them with new drivers. Taking his cue from the recent reworking by A&M Records in Hollywood of its four older boxes, McCune directed engineer Matt Hock to create a new 2-way configuration: remove the old Electro-Voice tweeter horns and replace all the other drivers with more modern choices. The new JBL titanium/neodymium compression driver extended high enough on its own, obviating the need for the higher tweeter bandpass.

Sound tech/carpenter Dan Ritzo modified the enclosures. The old 4-conductor loudspeaker connector stayed in place; Hock was happy that he now had two simple amplifier circuits without a shared ground. Lightweight switching amps were placed into service, and a new crossover was designed.

The newly designated JMX model boxes were first installed and operated by Gary Lehman on Mount Tamalpais at the outdoor Mountain Play, with Allan McCune remarking that the system sounded very intelligible. Hal Soogian felt differently, deciding he would rather not mix on a JMX system.

Lehman worked the JMX a few more years, but it held the same internal flaw as in 1980: the new compression driver, even though it was lighter than the old alnico, was not adequately supported, and its mass eventually caused the horn throat to fracture in transit. As before, there was no solution for a shattered horn. The parts were cannibalized and the enclosures thrown out, closing the book on this final experiment.

Legacy & Influence

With so many JM-3s sitting unused in the warehouse, a few of them ended up in private ownership, either bought officially by McCune techs or otherwise spirited out of the warehouse to power rehearsal rooms or parties. Four JM-3s are still owned by McCune, the four that were mounted in the Venetian Room for many years. In December 2017. McCune Sound Service was bought by Atlanta-based Shepard Exposition Services, who slowly phased out the McCune brand. The fate of the four JM-3s is not certain.

The company’s stubborn policy against selling the JM-3 resulted in fewer people knowing about it during its lifetime. McCune pictured itself as a rental and production house and didn’t want to branch out into sales and manufacturing. The JM-3 project was costly – it nearly broke the company – and they wanted to control it as a rental item, thereby retaining top clients who required the JM-3 clarity and power in a compact package. But this policy greatly limited the reach of the radical new design.

JM-10 system hanging inside four-high scaffold. (Courtesy of Kevin Tyrrell, McCune Anaheim)

Competing proprietary cabinets were inspired by McCune’s achievement, starting with Clair Brothers hearing the JM-3 at a stadium event then pooling their own ideas for an all-in-one loudspeaker to create the S4 concert system in 1974. (The S4 wasn’t fully horn loaded but it landed every punch.) A few years later, Showco brought out the driver-packed Pyramid system, the precursor to its highly successful Prism.

But these were not for sale! The idea of a professional loudspeaker tuned with integrated electronics was only made available for purchase when Meyer Sound reworked the processor/amplifier concept into the 2-way UM-1 UltraMonitor for Jefferson Starship in 1979. John Meyer founded the company to bring the integrated professional loudspeaker to the masses. The direct descendants of the JM-3 and JM-10 were Meyer’s MSL-3 and MSL-10 concert loudspeakers, clearly following a similar naming scheme.

A less obvious descendant is the Meyer UPA 2-way trapezoid loudspeaker, created in 1980 at the request of Abe Jacob for Broadway theatre using many of the same ideas, including a proprietary loudspeaker processor. The UPA was wildly popular with sound companies and installers, blazing a path into the future. The UPA served as Meyer’s flagship loudspeaker for nearly four decades, changing from passive to self-powered in 1995, thus ushering in a new era.

The author thanks John Meyer, Bob Cavin, Abe Jacob, Pat Maloney, Allan McCune, Dennis Minnick, Kevin Tyrrell, Matt Hock, Dan Ritzo, Chris Michie, Greg Kirkland, Terry Simmons, Lee Brenkman, Greg Oliva, Dan Bouchante, Dave Terp, Dave Johnson and Hal Soogian for their input.

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