The Rock in Rio festival made its US debut when it set up in Las Vegas at the MGM Resorts Festival Grounds for two weekends in May, drawing 172,000 fans from around the world to see the likes of Taylor Swift, Bruno Mars, No Doubt, Metallica and Linkin Park.

The festival’s main stage again used JBL VTX line arrays powered with Crown I-Tech HD amplifiers, while the Mercedes-Benz Evolution stagewas equipped with a Martin Audio MLA system. Audio was provided by Gabisom Audio Products Brazil, Rock in Rio’s longstanding production partner, with Las Vegas’ own 3G Productions who assisting with set-up, stage gear and production.

In addition to Rio – where it was first staged in 1985 – the festival has been held in Lisbon and Madrid. This year’s US festival marked an important expansion for the event and for its founder, Roberto Medina.

The line-up on the Mercedes Evolution stage for both the Rock and Pop weekends featured Foster the People, Gary Clark Jr, Sepultura featuring Steve Vai, Deftones, Coheed and Cambria, Jessie J, Charli XCX, Joss Stone, Magic!, Tove Lo, James Bay, Mikky Ekko among others others. The MLA system, meanwhile, featured 16 MLA enclosures with one MLD per side along with 32 MLX subwoofers groundstacked in front of the stage, and 12 MLA Compact on top of the subs for additional front and ground fill. It handled the diverse line-up, providing consistent coverage, clarity and low-end from front to back of the 426-ft deep audience area without the use of delay towers.

‘We were able to cover the audience with more than enough SPL and then reduce it dramatically just beyond that for the VIP area near the Hilton,’ says Chris Pyne, a Martin Audio engineer who specialises in MLA and worked the Rock weekend. ‘Equally, thanks to MLA technology and Display, tuning was a breeze, taking less than 15 minutes. It sounded great, every engineer was very complimentary and they all said it was one of the easiest shows they’d done.

‘Dwayne Baker, FOH Engineer for Theophilus London said: ‘It’s an amazing sounding rig and it was such a pleasure to mix on. Basically, everyone was very happy with MLA.’

Martin Audio R&D Director Jason Baird was on hand to answer questions about MLA and engage with FOH engineers, Gabisom, and invited guests for a special system demo held before the Pop weekend shows. Asked about challenges presented by Rock in Rio, he comments: ‘The way the system was used in a typical large, flat festival layout, the most problematic aspects were the low night-time temperatures and lack of humidity, which are challenges for any PA system. The resulting high frequency attenuation over distance was overcome by programming the correct parameters into Display. The objective was maintaining those crispy, clear highs MLA is known for, but in very low humidity conditions, at distances of over 400 ft, and we managed to maintain excellent high frequency extension right to the end of the coverage pattern.’

In terms of the differing musical requirements of the various artists, he says: ‘We didn’t have to make any changes from one act to another.’

‘The front fills didn’t have a lot to do because the MLDs at the bottom of the arrays were doing such a great job,’ he adds. ‘They were needed at the centre by the barriers. The MLX subs sounded very even throughout the coverage pattern and we matched the pattern of the sub array to the MLA system. It was pleasing to be standing 400 ft away and have the subs tugging slightly at your clothes, but not giving you a headache. Up on stage, the spill from the MLA and subwoofer array was incredibly quiet, leading some at the demo to think we’d pulled the faders down, yet a few feet further forward it was producing thunderous lows.

‘The reactions from our Latin American guests were exceptionally positive,’ he concludes. ‘It was nice to see genuine enthusiasm on the faces of people who’ve been in the audio business for years. First and foremost, they were excited because of the sound quality and how it is delivered over such great distances without using any delays. That was the thing they latched onto. If you stand by FOH, you expect it to be loud and sound good, but when you walk 200 ft. further away and it still sounds loud and good in a very consistent manner, that made them think differently about MLA and the products they’re currently using.’

Back on the main stage, Gabisom provided a massive main JBL loudspeaker system arranged in the typical Rock in Rio format, which Gabisom refers to as a ‘side-by-side’ configuration – four hangs, each containing three columns of loudspeakers. The columns closest to the stage (which Gabisom calls the ‘band’ columns) received a full band mix, minus vocals or any other element of the mixing engineer’s choice. The middle columns were comprised of flown subwoofers, whose feed was derived from the Band mix, creating a four-way flown system. The outer columns ‘vocal’ columns, received a vocal mix, along with any other elements that the mixing engineer chose.

‘In this way, we guaranteed that each independent system [band or vocal] would not be fighting one another for headroom, allowing full, clean power with no limiting, clipping or acoustical distortion,’ says Gabisom Chief Engineer, Peter Racy. ‘This newly found headroom was present right at the mixing console’s summing amps and output buses, in the system processors and power amps, as well as the speaker components. The result was clean, powerful sound.’

The PA system called on 128 VTX V25 line array elements, 46 VTX S28 flown subwoofers and 24 VTX G28 groundstacked subwoofers. A total of 124 Crown I-Tech 12000HD amplifiers powered the system, which was networked via JBL HiQnet Performance Manager.

As is typical for outdoor concerts in Las Vegas, the climate posed a challenge from a technical perspective. ‘With relative humidity as low as eight per cent and gusty winds lifting dust into the air, we tuned various parameters within Performance Manager, including band-pass gain, subtractive EQ on the low-mids and additive EQ on the highs,’ Racy reports. ‘This is quite unusual for the VTX system, on which we normally make a few changes, if any.’

However, once Gabisom dialled in the atmospheric compensation, the system performed exceptionally: ‘Guest mixing engineers were all very happy with their results, and all had favorable comments on the system,’ Racy says. ‘The Performance Manager software was a huge asset for both tuning and monitoring the entire system, giving us the confidence that the system was healthy at all times.

‘The VTX V25 system has been Gabisom’s system of choice for large outdoor festivals and high-power rock and electronic dance music concerts, due to its high power capability and superb audio quality,’ he concludes. ‘It does the job exceedingly well in an effortless manner.’

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