{{< MultiGalleryComponent galleries="pyramid-pa-project, pa-parking-lot-test" >}} In 1978 we decided that Showco needed to design a sound system that used full range enclosures with built-in rigging hardware to replace our four-way sound system that used external three-layer rigging platforms to rig individual cabinets including the hurler bass cabinets, the mid bass fiberglass horns, the JBL 2350 horns with 2480 drivers for mid-range and the JBL 2390 horns with 2470 drivers for high frequencies. Keny Whitright left Showco in 1978 so Ron Fox and Jim Bornhorst designed the new sound system using the pyramid design that Showco had patented in 1974. Ron and Jim designed a system that consisted of three enclosures-a bass cabinet with four JBL K140 15” speakers in a pyramid folded horn loaded configuration and a short throw and long throw three-way cabinet with two JBL K120 12” speakers in a pyramid folded horn loaded configuration for mid-bass, two radial horns with JBL 2482 drivers for mid-range and 24 Motorola piezo tweeters for high frequencies. The system would be powered by Crown 300A amplifiers and Crown PSA-2 two channel power amplifiers that delivered 275 watts per channel into 8 ohms, 460 watts into 4 ohms and 915 watts into 8 ohms in bridged mono mode. Each cabinet had two steel recessed cups on the top and bottom with rigging eyelets connected together by a ½” steel threaded rod that ran all the way through the cabinet like the M4 cabinet that Keny Whitright designed in 1974. {{< StoryImage id="showco-80-pyramid-pa" title="Pyramid System lineup" caption="Showco Pyramid System left to right, bass cabinet, short throw three-way cabinet, amplifier rack with Crown DC300A and PSA2 amps, long throw three-way cabinet, bass cabinet." credit="Photo Recovered Showco Archive" size="medium" >}} ## Jim Bornhorst’s Comments on Pyramid System Design 1979 Ron and I were both still heavily committed at Showco Manufacturing when Rusty asked us to work on the development of a new arena PA intended for the Bee Gees tour beginning late summer 1979. I was more involved at Mfg. than Ron at the time as his speaker line was quite mature. I still had two active projects in the pipeline, a new mixer and a master panel/crossover, to which our new hire John Covington was actively contributing. However, John was soon shanghaied to work on the Bee Gees’ dance floor controller which was woefully behind schedule at Showco Inc. leaving me single handed. Ron did almost all of the acoustic and packaging design work as his woodworking skills and success with the Hi Fi speaker had proven his abilities with his pyramid loading concept. My contribution mainly consisted of acoustic testing along with throwing out a few ideas here and there. I had built an acoustic testing room in the back of our warehouse that was lined on 5 sides with thick insulation in an attempt to simulate an anechoic chamber. I had made tall, insulated cylinders and polygons and scattered them around in the room to break up reflections and standing waves. I originally built the facility to support Ron on the Showco HiFi speaker and got pretty good data down to around 100 Hz or so. I used a Brüel and Kjœr (B&K) Type 2203 measuring microphone connected to a Tektronix analog swept spectrum analyzer which displayed on an analog storage scope. A pink noise generator was the signal source used to make most measurements and an X-Y plotter drew frequency response and polar pattern plots. Acoustic harmonic distortion measurements were made by hand using an HP 334A and the B&K 2203. In the past, Showco had built mid-range radial horn cabinets with dual or even quad drivers coupled to the horn. They were well known for their distortion at 2kHz which I had measured in the past. Ron and I decided that if possible, the new system use a single driver compact horn combination to eliminate the throat distortion that was inherent using multiple drivers. I believe it was Ron who found the Renkus Heinz SSH820 cast aluminum horn, a departure from our usual selection of JBL components. Its 2 inch throat matched JBL’s new 2482 driver making a very compact package. The horn and driver measured quite well and the 2482’s 4” aluminum edge-wound voice coil could handle 120 Watts of continuous program power at an efficiency >110 dB SPL @ 1m. While I was measuring, Ron was busy designing a bass and a companion 3-way cabinet. He chose to go with a rectangular cabinet that would have the same external dimensions for both the bass and the three-way cabinets and use the same cup and rod hanging hardware as was used in 1974 for the M4 cabinets. Ron’s columnar four-15” speaker design was a folded horn with each rear-firing speaker loaded with a pyramid reflector nestled in the cone of the speaker. The sealed vertical speaker box was wedge shaped which formed an expanding “horn” with the enclosure walls on both sides. Ron wanted those outer walls to be curved allowing a more uniform expansion of the sound pressure so he made the curved walls out of fairly thin MDF to facilitate bending into a curve. He had fabricated curved ribs behind the MDF for stiffening but the walls were still quite resonant. I suggested using a urethane foam filler in the space between the outside wall and inner horn surface. The foam helped a lot but was extremely messy and time consuming to deal with. I’m not sure it was worth the effort.

{{< StoryImage id="showco-012-pa-work-79" title="Fabricating bass cabinet" caption="Fabricating the curved walls of the Pyramid system bass cabinet." credit="Photo Recovered Showco Archive" size="medium" >}} {{< StoryImage id="showco-050-pa-work-79" title="Three-way cabinet interior" caption="Interior of the Pyramid three-way cabinet." credit="Photo Recovered Showco Archive" size="medium" >}}

The 3-way box mid-bass section was another folded horn using two 12” pyramid-loaded speakers side-by-side and rear firing into the folded vertical horn. I suggested that the mid-range horns be mounted on the front surface of the sealed speaker box in an edge-to-edge vertical configuration where the patterns from the two horns would just overlap and cover a vertical swath in the hall sweeping from the upper decks to the floor. Ron calculated the angle which worked in the physical design pretty well. Two of the bands of the 3-way box were pretty well set. Measurements showed that both mid-bass and mid-range performed well and delivered lots of acoustic power. The bass box was tested by ear as my little room wasn’t much use at low frequencies. {{< StoryImage id="showco-061-pa-work-79" title="Three-way cabinet 1978" caption="Showco Pyramid system three-way cabinet 1978." credit="Photo Recovered Showco Archive" size="medium" >}} We must have built a second prototype 3-way box as there is a picture of one with the other two cabinets but I don’t remember it. I assume its purpose was a long throw application as the two Renkus Heinz horns are shown stacked side-by-side and facing directly forward to couple and project. The hi-band components were critical to the design and presented a difficult decision. If we chose to use JBLs 2402 or 2405 we would have to buy them new. Both were expensive, delicate, heavy and didn’t project or couple well in groups to reach the back of arenas. The 2405 also didn’t go low enough to work with the radial horns. We had been using Motorola’s bullet piezoelectric tweeters in the Manufacturing disco product line as well as in Showco’s arena four-way PAs for a few years, but they had a reputation for being a bit screechy especially in arrays. They were not considered a “professional” product. However, Motorola had just released an improved piezo driver and horn that Ron had been sampled. My measurements showed that it had a smooth frequency response and controlled pattern that did not beam at higher frequencies. The 2” X 5” unit worked down to around 3k Hz so it paired well with the radials. Ron mocked up a few arrays and found they worked quite well together in groups so we decided to stick a bunch of them on the front facets of the mid-bass speaker enclosure alongside the radials. The system seemed to work well in shop tests so we went into full production on the first system. The first tour booked for the system was with The New Barbarians beginning at Crisler Arena in Ann Arbor Michigan on April 24th, 1979 and ending on May 22,1979; a short tour with Kieth Richards, Ron Wood and Stanley Clark’s new power trio. This was a proof of performance gig before the Bee Gees took it on a massive tour that fall. Rusty, Ron, “Fuzzy” Evangelista (a structural engineer who designed the rigging system for the Pyramid system) and I all flew to Ann Arbor for the setup and first show. The tour color was red and we had made custom red grill cloth front covers for the system. Load in, rigging and sound check went well but the show sound was disappointing in that the system lacked good deep bass. Vocal performance was good though.

{{< StoryImage id="showco-012-new-barb-stage-79" title="New Barbarians stage" caption="Showco Pyramid system with red grill cloths and Showco lighting rig for New Barbarians tour 1979." credit="Photo Recovered Showco Archives" size="medium" >}} {{< StoryImage id="showco-30-new-barbarians-1979-bw-014-barbarians-79-bw" title="Ron Fox and Rusty Brutsché" caption="Ron Fox and Rusty Brutsché at New Barbarians tour 1979." credit="Photo Jim Bornhorst" size="medium" >}}

We subsequently built subwoofers that went under the front of the stage for the Bee Gees tour which complimented the system, four subwoofer cabinets per side. (See photo at the end of this section). The hanging bass bins were solid and efficient but the folded horn just didn’t go low enough to complete that all-important 40-60Hz low range. The Pyramid System, with subwoofers, served Showco well for a few years until digital technology allowed acoustic magic that was unimaginable in 1979. The next chapter in Showco’s PA development saga, The Prism System, was truly revolutionary. Jim Bornhorst ## Rusty Brutsché Comments on Pyramid System 1979-

{{< StoryImage id="showco-049-pa-work-79" title="Mounting mid-bass speakers" caption="JBL K120 12” mid bass speakers being mounted into the Pyramid three-way cabinet. The speakers were acoustically loaded by pyramid shaped baffles on the rear cover into a W style folded horn." credit="Photo Recovered Showco Archive" size="medium" >}} {{< StoryImage id="showco-048-pa-work-79" title="Mounting bass speakers" caption="JBL K140 15” speakers being mounted into the Pyramid bass cabinet. The back of the cabinet had four pyramid shaped baffles that loaded the 15” speakers acoustically into the folded horn that had curved sides leading out to the mouth of the cabinet." credit="Photo Recovered Showco Archive" size="medium" >}} {{< StoryImage id="showco-047-pa-work-79" title="Bass speakers ready" caption="JBL K140 15” speakers waiting to be mounted into the Pyramid bass cabinets." credit="Photo Recovered Showco Archive" size="medium" >}} {{< StoryImage id="showco-044-pa-work-79" title="Mid-bass mounting holes" caption="Mounting holes for two JBL K120 12” mid-bass speakers in Pyramid three-way cabinet. The back of the cabinet had a pyramid shaped baffle that loaded the 12” speakers acoustically into the W shaped folded horn that exited the front of the cabinet. The two drivers down inside the cabinet are JBL 2482 mid-range drivers mounted on radial horns." credit="Photo Recovered Showco Archive" size="medium" >}} {{< StoryImage id="showco-046-pa-work-79" title="Cable compartment" caption="Cable compartment on the top rear of the three-way cabinet that housed a multi-pin cable that connected to the amplifier racks with the Crown DC300A and PSA-2 amplifiers and a pigtail to connect the bass cabinet to the bass amps through the multi-pin cable." credit="Photo Recovered Showco Archive" size="medium" >}} {{< StoryImage id="showco-034-pa-work-79" title="Bass cabinet" caption="Bass Cabinet for the Pyramid system. The rear cover with the four pyramid shaped baffles loaded the four 15” speakers acoustically into the folded horn that exited at the mouth of the cabinet. The inside walls of the cabinet were curved to a specific horn shape." credit="Photo Recovered Showco Archive" size="medium" >}} {{< StoryImage id="showco-024-pa-work-79" title="Rigging cups" caption="Pyramid bass cabinet showing two recessed steel cups on the top and the bottom with rigging eyelets that are connected together with threaded steel rods that extend all the way through the cabinet." credit="Photo Recovered Showco Archive" size="medium" >}} {{< StoryImage id="showco-022-bgs-pa-79" title="Parking lot rigging test" caption="Jack Maxson operating the chain motors for the rigging grid for the Showco Pyramid system during a parking lot test of the new system. The bass cabinets were rigged first and are on the top layer and the three-way cabinets are rigged on the second layer under the bass cabinets. The ratchet straps adjusted the tilt angle of the three-way cabinets. The storage compartment for the speaker cable pigtails is at the top of the three-way cabinets. The silver cables are the multi-pin speaker cables going to the amp racks with the Crown DC300A and PSA-2 power amplifiers and the black cables connect the bass cabinets to the multi-pin speaker cables. Ten Pyramid cabinets were mounted on the rigging grid and two CM 1-ton chain motors were required to lift the speakers into position. A typical indoor Pyramid system had four hanging grids with 20 bass cabinets and 20 three-way cabinets." credit="Photo Recovered Showco Archive" size="medium" >}} {{< StoryImage id="showco-023-bgs-pa-79" title="Hanging grid test" caption="Front view of one hanging grid of Showco Pyramid speakers. This photo is of a test setup that we built in the parking lot at 9011 Governor’s Row to test the rigging and the acoustical performance of the speakers." credit="Photo Recovered Showco Archive" size="medium" >}} {{< StoryImage id="showco-067-pyramid-amp-racks" title="Amplifier racks" caption="Amplifier Racks for the Showco Pyramid system. Each rack powered two bass cabinets and two three-way cabinets. The two Crown DC300A amps in the bottom of the rack were configured in mono 600 watt mode and each powered four JBL 15” speakers in a bass cabinet. The DC300A above the bass amps powered the mid bass speakers with each channel powering two 12” speakers and the Crown PSA-2 at the top of the rack powered four JBL 2482 mid-range drivers on one channel and 48 Motorola piezo tweeters on the other channel. Not shown are Crown PSA2 amplifiers that powered the subwoofers with one JBL 18” subwoofer on one channel of each PSA2." credit="Photo Recovered Showco Archive" size="medium" >}} {{< StoryImage id="showco-068-pyramid-system-sub-woofers" title="Subwoofers" caption="Subwoofers were designed for the Pyramid system with an JBL 18” speaker in a folded horn “W” enclosure. Four subwoofers were positioned on the floor on each side of the stage under the hanging speaker grids." credit="Photo Recovered Showco Archive" size="medium" >}}

## New Barbarians Tour 1979- {{< MultiGalleryComponent galleries="pa-shop-prep, show-setup, show-shots, 29-new-barbarians-apr-1979, 30-new-barbarians-apr-1979-bw" >}} The New Barbarians, a band featuring Keith Richards and Ronnie Wood, embarked on a US tour in 1979. The tour included 19 shows across the US in April and May, along with two concerts in Canada and a performance at the Knebworth Festival in England supporting Led Zeppelin. The band members included Keith Richards, Ronnie Wood, Stanley Clarke, Ian McLagan, Bobby Keyes and Zigaboo Modeliste. Showco supplied both sound and lighting and the new Showco Pyramid sound system was used for the first time.

{{< StoryImage id="showco-010-barbarians-79" title="New Barbarians 1979" caption="L to R Ian McLagan, Bobby Keyes, Ronnie Wood, Keith Richards, Zigaboo Modeliste, Stanley Clarke." credit="Photo Jim Bornhorst" size="medium" >}} {{< StoryImage id="showco-001-barbarians-79" title="New Barbarians 1979" caption="L to R Ronnie Wood, Keith Richards, Stanley Clarke." credit="Photo Jim Bornhorst" size="medium" >}}

## Texxas Jam at the Cotton Bowl June 9, 1979- {{< GalleryComponent id="33-texxas-jam-cotton-bowl-jul-1979-bw" >}} We used the new Pyramid sound system along with five of our standard indoor four-way systems for the Texxas Jam at the Cotton Bowl in Dallas on June 9, 1979. The artists on the show included TKO, Sammy Haggar, Nazareth, Van Halen, Boston, Heart and Blue Oyster Cult was the headliner.

{{< StoryImage id="showco-006-cotton-bowl-79-bw" title="Texxas Jam PA" caption="Five standard Showco four-way sound systems augmented by 24 JBL 2356 long throw horns with JBL 2482 drivers and one indoor Pyramid system (not shown) for the Texxas Jam at the Cotton Bowl in Dallas on June 9, 1979." credit="Photo Jim Bornhorst" size="medium" >}} {{< StoryImage id="showco-33-texxas-jam-cotton-bowl-jul-1979-bw-007-cotton-bowl-79-bw" title="Pyramid at Cotton Bowl" caption="Showco Pyramid sound system used for the Texxas Jam at the Cotton Bowl on June 9, 1979 along with five standard Showco four-way sound systems (not shown)." credit="Photo Jim Bornhorst" size="medium" >}} {{< StoryImage id="showco-33-texxas-jam-cotton-bowl-jul-1979-bw-004-cotton-bowl-79-bw" title="Showco sound system" caption="Showco sound system for the Texxas Jam at the Cotton Bowl on June 9, 1979." credit="Photo Jim Bornhorst" size="medium" >}}

## Willie Nelson’s 4th of July Celebration June 30, 1979- {{< GalleryComponent id="34-willie-nelson-picnic-sep-1979" >}} Showco provided the sound and lighting systems for the Willie Nelson’s 4th of July Celebration on June 30, 1979 at the Pedernales Country Club in Austin, Texas. {{< StoryImage id="showco-002-willie-79" title="Willie Nelson celebration" caption="Showco sound system and lighting system for the Willie Nelson 4th of July Celebration on June 30, 1979 at the Pedernales Country Club in Austin, Texas." credit="Photo Jim Bornhorst" size="medium" >}}

Showco History