Trip Khalaf: Behind The Wall — Engineering Roger Waters' World Tour

Interview | Engineer
By Mark Cunningham

Live sound engineer 'Trip' Khalaf and his colleagues talk about touring Pink Floyd's classic 1979 album with band co‑founder Roger Waters.

To say that Roger Waters' re‑imagining of Pink Floyd's original tour of The Wall is 'big' would seem to be stating the obvious. In actual fact, 'big' doesn't begin to cover it.

A masterstroke of large‑scale arena production and complex beyond comparison, The Wall Live cost $59 million to develop. It boasts razor‑sharp, ultra‑widescreen projection of some of the most creative video content you are likely to see in a concert environment; surround sound; pyrotechnics that will scare the life out of you; props (including updates of the trademark Teacher, Wife and Mother puppets from The Wall); and the omnipresent inflatable Pig.

The cardboard bricks used to build the famous Wall arrive flat packed, and are assembled by the crew.
Separated into two 55‑minute halves, The Wall is accurately recreated this time round by Waters (playing bass, acoustic guitar and trumpet) and his tightly rehearsed 11‑piece band, comprised of drummer Graham Broad, guitarists Dave Kilminster, Snowy White and GE Smith, keyboard players Jon Carin and Harry Waters (Roger's son), vocalist Robbie Wyckoff — who handles David Gilmour's original parts — and backing singers Jon Joyce, Kipp, Pat and Mark Lennon.

Then, of course, there's the Wall itself. This arena‑width monstrosity, first unveiled in 1980, led critics to equally praise Waters' conceptual vision as condemn him for his "millionaire rock‑star indulgence”. It currently stands 35' high and averages around 240' wide, depending on the scale of the venue. It's fashioned from around 400 cardboard bricks of 5' x 2.5' that arrive flat‑packed for assembly by the crew.

During the first half of the show, the band gradually disappear from view and the wall is slowly built. Thereafter it acts as a widescreen surface for the truly jaw‑dropping projection, featuring political statements and many of Gerald Scarfe's original animations. At the show's climax, the wall comes tumbling down under precise computer control, and the band — which included the Floyd's David Gilmour and Nick Mason for one night only at London's O2 Arena, May 12th — re‑emerge amidst smoke and debris for the acoustic finalé of 'Outside The Wall'.

Production design for the tour was headed by an icon of the industry: Mark Fisher. It's important to understand that this is a modern take on Pink Floyd's original 1980‑81 performances of The Wall, as it harnesses a wealth of technology that didn't exist back then. On some levels, though, you'd be hard‑pressed to spot the difference. I suppose I should be a good judge: after all, I was there for The Wall the first time around, at Earls Court 30 years ago, and even carried a few flightcases!

Any show that features 'Comfortably Numb', 'Run Like Hell' and 'Hey You' has something going for it, but if none of this is making your eyebrows twitch, take a look at the figures. Opening in Toronto on September 15, 2010, the first leg of the tour grossed over $89.5 million from 56 concerts, and was the second‑highest grossing concert tour in North America last year.

By the end of the tour — which looks set to be next March — The Wall Live will have completed 140 shows to nearly two million people and taken a colossal $200,000,000 at the box office. Remember the sound of the cash register on Floyd's 'Money'? It's now working overtime!

We Don't Need No Digital

Trip Khalif is pictured (right) with system technician Bob Weibel (left). The Yamaha PM5D in front of trip is not the main mix console; he prefers the sound of analogue Midas consoles, also pictured.
In the live sound hot-seat at front of house is James 'Trip' Khalaf, who also doubles as Roger Waters' tour manager. It's a convenient, lucrative add‑on to the FOH sound role he has been performing at leading American rental company, Clair, since the early 1970s. Queen, Michael Jackson, Madonna, Steely Dan, Kiss, Mariah Carey and Peter Frampton are just a few of the major artists to benefit from his extensive skills over the past 38 years.

Khalaf, who came into The Wall Live project last year at the end of a "really fun” summer on the road with Kiss, divides his show mix between two Midas XL4 'old school' analogue consoles and a Yamaha PM5D digital board. Since the show is effectively split across two stages, the primary XL4 handles all of the live band inputs on the main stage; the secondary XL4 takes care of the instruments on the fore‑stage during the 'Run Like Hell' set.

It's also interesting to note that there are two sets of backline equipment. One set is for the main stage, while the other emerges from the fore-stage using elevators, shortly after 'Comfortably Numb' is played in the second half. It then disappears after 'Waiting For The Worms'.

The PM5D deals not only with the surround-sound effect inputs and the routing that drives the surround system, but also with orchestral playback and the returns from all the analogue effects. These are all summed and delivered back to Khalaf on his primary XL4.

Notoriously loyal to the analogue medium, Khalaf physically baulked when I suggested that most engineers in 2011 would have chosen a fully digital mixing solution for a show of such grandiose scale. I should have predicted his dismissive reply...

"Why? Digital sucks, but I see a lot of engineers these days going down that route. I just look on rigidly in amazement, as if they are insane. The pretending has become a bore. Digital consoles don't sound good but, OK, there is a place for them. If you're mixing a 'hard‑drive pop' show, where you've got a different kick drum coming at you for each song, it makes sense. But Roger's show is the polar opposite of that.

"This is a situation where you have extraordinarily good musicians playing live, and in my mind it would be ludicrous to suggest reducing their sound to mere ones and zeros. I will now wait patiently for every digital mixer company to complain and send me hate mail. I deserve the rap. Yes, I use a PM5D, but that serves a specific function — effects routing — so the application is very different. Would I put Roger's vocal through it? What do you think?

"Was the original album of The Wall recorded digitally? No. Did it sound good? Yes. That's pretty much the core of my argument here. I've been a Midas analogue user for longer than I can remember and you'd have to drag me away kicking and screaming to get me off the damn thing. So call me a dinosaur... what do I care?”

Interestingly, Midas consoles were on duty at the original Floyd shows. James Guthrie mixed at FOH using a UV‑lit Midas 40‑channel custom desk, which grew with the addition of several 24‑ and 10‑channel stretches as rehearsals progressed. Behind the wall, Seth Goldman ran an extensive monitor system with a Midas Pro 2 console for the main stage and another Midas with Pro 2 and Pro 4 modules, for when the band performed on the fore stage.

Throughout the tour, Khalaf has made a number of suggestions for improving the audio, particularly the surround FX. "Sometimes, Roger takes on board what I suggest; at other times, he's told me to fuck off! It's Roger's gig, that's his right and, like I say, he doesn't pull any punches.” Either way, The Wall tour's analogue heritage is very strong indeed.

James Guthrie, who co‑produced the original 1979 double album, went back to the analogue multitrack tapes to restore and digitally transfer all of the original album's sound effects, including the helicopter, battle sounds, plane crash and the Islington Green School Choir heard on the last UK No.1 single of the '70s, 'Another Brick In The Wall (Part 2)'.

Trip: "Through myself, James Guthrie (long‑term Pink Floyd and Waters co‑producer and engineer), Mike McKnight (system programmer) and Roger, these sounds magically appear above the audience's heads every night.

"Roger invites local choirs from each city we play and they sing along over the 'lift' of the original choir recording,” says Khalaf. "We started off triggering the choir from Jon Carin's keyboard but it wasn't sounding right so James helped us out. He re‑did the orchestral parts and generally cleaned up those critical items, and did a great job. Those come to me at front of house from Mike McKnight's playback rig.” (See the 'Mike The Middle Man' box).

Effects & Mics

One might assume that, on a show of this size, the pair of Midas XL4s would be accompanied by a real‑estate munching arsenal of outboard, but in reality the rack is relatively modest. Eventide H3000 Ultra Harmonizers, TC Electronic delays, a TC‑Helicon vocal doubler, Lexicon PCM90 and 91 reverbs, Summit TLA 100A tube amps and Dbx 900 compressors for vocals, Crane Song STC8 compressor limiters for bass and Aphex expanders and gates for drums are the notable rackmount features.

One of the few effects racks used for the show, including many units familiar to studio producers, such as the Summit Audio TLA 100A tube limiters used for Roger and Robbie's vocals and a Cranesong STC8 used for the bass.

Says Khalaf: "You can approach this from two angles: try and make this sound as close to the record as possible, or take a looser view on it, retaining all the crucial hooks that people will remember and expect. I think that making it sound too much like the record would rob the audience of a lot of the inherent power of the performance.”

I particularly noticed that during 'Comfortably Numb', Khalaf didn't hold back with the master fader. "Ah, you noticed that,” he smiles. "It's the only time in the show when I do that. I just love taking the audience's faces off when we do that number, and it's the highlight for me. It's incredible.”

Does Khalaf take advantage of the programmable snapshots on the XL4? "They're there but I tend to use the VCAs and mutes for the most part. I look at each show with fresh eyes, or rather ears, because they are human beings on stage: maybe the drummer will play harder the next night, for example. Plus you're faced with a new set of acoustic parameters at each new venue. What helps me most is the experience of the musicians, who know how to control themselves.”

The selection of microphones used for the show is quite 'vanilla', with Shure wireless U4Ds in evidence for the backing vocals, while Waters and Wyckoff stick to the old standard Shure SM58s (wired and wireless) for their vocals, and for Graham Broad's main and fore stage DW drum kits. Further Shures are used on the kick drum and snare (SM91, Beta 52 and SM57s), while Audix D2s are applied to the toms and Milab DC96s are paired as overheads. Audio‑Technica AT4050s take care of all the guitar amps.

Mixing Monitors

The Digico SD7 console is used to handle monitor mixing for the show. Note that the set-list has been programmed into the console.
When the tour began a year ago, the man charged with handling the stage monitor mix was Robin Fox, another veteran of the business who reprised his role from the original Wall shows back in 1980‑81. After leaving the entourage at the end of the North American leg, he was replaced by Ian Newton (another highly experienced touring pro) just in time for the Lisbon rehearsals that preceded the European leg this spring.

In complete contrast to Trip Khalaf's setup, Newton's is a wholly digital affair. "I just came in and took over using the equipment that Robin had, because there wasn't any point in changing anything. I'd never used the DigiCo SD7 before but it's a fine piece of kit that's been behaving well, and I found my way around it easily enough. I'm running close to 130 channels and the internal reverbs and delays tend to be quite busy on acoustics and vocals, but it's easy to keep track of.”

The fore‑stage is deceptive in that it appears to be monitor wedge‑free, but there are over 30 Clair 12AM Series II wedges positioned underneath, projecting up through grilles. Further 12AM IIs were in evidence behind the line of the wall, where the band live for most of the show. Waters himself is surrounded by four wedges. There's a concession to drummer Graham Broad in the shape of a single sub‑bass cabinet backing up his 12AM, but generally speaking, the monitoring is in‑ear, which is essential since everyone is following a click track driven by timecode. It's a far cry from the simple headphones worn by Waters 30 years ago!

This line array is part of the Clair i5 PA system. Two versions were used on the tour, including an i5D prototype with improved low end.

"Most of the musicians are on the new JH Audio wireless ear pieces from Jerry Harvey (formelry of Ultimate Ears) and they're run with Sennheiser G3 hardware,” says Newton.

"They obviously all have different needs, mix‑wise, but Roger has a stereo mix of everything which, for me, is fantastic to listen to. Some of the guys wear one ear piece and listen to their wedge, which isn't unusual.

"As well as the music, there are pre‑recorded count‑in cues, so some of the band are listening out for them: it's just so 'bang on'. Graham has his own personal Samson mixer which allows him to adjust the level of those cues and the rest of the music, which I sub‑mix over to him. Jon Carin has a small Mackie mixer for similar reasons.”

Newton is supported by monitor technician Kevin Kapler, who is also the primary wireless systems co‑ordinator. This is a very significant position on this production, given the amount of frequency 'negotiation' required for wireless in‑ears, mics and instrument packs. Regulations regarding wireless communications can differ depending on the country the show is in, which also affects the frequencies used.

"Kevin arrives early and spends a long, busy day scanning for wireless frequencies,” explains system technician Bob Weibel. "The wireless instrument packs are Samson, as the band have a relationship with the brand, but we provide Sennheiser System 2000 systems for the in‑ears. That was a key choice because we needed the frequency agility in order to deal with the regular touring environment and give the optimum RF performance.”

Line Array Design

Roger's four Clair 12AM II wedges provide him with a monitor mix during parts of the show.
Khalaf has been accompanied at the FOH position by his right hand man, system technician Bob Weibel, as he put it: "on more tours than I could possibly ever count… we go back a long way”.

It's Weibel's day‑to‑day responsibility to set up, tune and maintain the Clair PA system which, on the first American leg, was the Pennsylvania‑based company's prototype i5‑D line array. It's the latest in a long series of audio innovations from the company that stretch back to 1966, when it was founded by brothers Roy and Gene Clair. Soon after The Beatles' pioneering concerts at New York's Shea Stadium paved the way for larger scale tours, the Clairs saw that sound reinforcement in its then present state would not be able to deliver appropriate level of fidelity, and set about raising the bar.

"In the new i5‑D, the same drivers and elements are there [as in the previous version], but they're arranged a little differently, and the cabinet is designed to accommodate two 18-inch drivers instead of one,” says Weibel. "The sound ends up being significantly wider and somewhat deeper.”

"This tour was the first real practical challenge for the i5‑D” Khalaf adds, "which gets my vote simply because it's so coherent. At Clair, the principle is to fly as much low end in the roof as possible, and use the sub‑lows to couple more effectively with the floor.

"The lighting guys aren't so keen on the flying speakers but the people at the front who have bought the tickets prefer it, because they don't get murdered by an onslaught of sub‑bass coming from under the stage. The subs at the front are there but their output is greatly reduced and the result is more natural.”

By the time the tour reached Europe, this prototype had been transferred to Bon Jovi, so the standard JBL‑loaded, Crown‑amplified i5 system was deployed. Using Clair's proprietary AlignArray software, Weibel is able to very accurately predict how this system is going to perform at each venue.

Surround sound is treated separately by dedicated tech Henry Fury. It's catered for by two clusters of cabinets flown midway in the arena, a third cluster flown centrally at the back, and Powersoft‑amplified subs mounted on the floor at the rear. At times, the deep, thunderous resonance of explosion FX noticeably startled the audience and reminded me of Earls Court in 1980, when Stephen Court's system produced a similar 'sensurround' effect.


Khalaf mirrors the feelings of many of the crew who believe that touring at this level can't get better than this. "The down side is that we're now reaching the end of the great, traditional rock & roll tours, so I'm making the most of this while I can,” he says.

"Having done The Dark Side Of The Moon Live and now this, well, the thought of going out and mixing guitars, bass, drums and some guy drooling into a microphone doesn't really cut it for me. I mean, this is such a privilege. This is the greatest thing in the world and I look forward to going out there every evening to ply my trade.”

Although the European leg is now complete, The Wall Live will continue its global trek in January when it arrives in Australia, while a further leg is planned in South America next March. Meanwhile, Waters fans are in for a treat, as a film of the concerts in Greece during July is being lined up for a DVD release, possibly by the end of the year. Time to raid the piggy bank?  

Bigger Than IMAX: Projecting Onto The Wall

The combination of Waters' creative director Sean Evans and video systems specialist Richard Turner has resulted in what will be regarded as the most mesmerising concert video production for many years to come.

"Roger and I see eye to eye creatively and he appreciates that I'll always go out of my way to get the best solution to any idea,” says Evans. "Conceptually, Roger didn't want this new version to be about the internal struggle of a rock star; he wanted to expand the narrative to reference the social, political and religious divisions that occur in today's world.

"Of course, there are some aspects of the original show's most famous images that you can't mess with, and we debated long and hard about how to make 'The Trial' work in this environment. The answer was to spend two months taking high resolution scans of Gerald Scarfe's original animation and hand paint every scene to achieve the required definition”.

Other original footage required subtle 'upgrades'. For example, Scarfe's dramatic 'Fucking Flowers' sequence from 'Empty Spaces', required that the flower stems were extended to fill the sides of the wall.

"Every nuance has to have meaning with Roger, so there's not a single piece of gratuitous content in the show. I did a lot of the 3D content using Cinema 4D and Maya software,” says Evans. "I learned a lot about Maxon's Cinema 4D throughout this project; it's been a hell of a learning curve, and with all the Macs that we bought to make this happen, we must be Apple's No. 1 customer!”

The wall was modelled in 3D, with the aim of enabling accurate projection on any given part of the wall. This was where Richard Turner's experience was invaluable. His task was to turn all of the kit supplied by XL Video into a Medialon‑driven system that trumps the size and resolution of the world's largest IMAX cinema screen, with its 8560 x 1620 pixel canvas.

Turner, who was working with Gorillaz immediately before The Wall Live, specified 20 Barco FLM projectors — five groupings of three HD20s for the front projection on the wall and five R22s to rear‑project on the circular screen. Show Group Production Services built custom three‑way cradles to accommodate the FLMs, in order to enable the best possible angles. Seamless images across all five portions of the projection are enabled by a set of custom shutters, made by Tait Technologies, which serrate the projector beam edges and enable a smooth blend of different sections.

The tour, says Turner, is a constant work in progress for the video team. "Roger changes subtle elements of the show all the time and if that affects content, we have to react quickly. That's why we have six Final Cut Pro projects on the go, so that we can manually write time code points for drop‑ins or cuts.”

Mike The Middle Man

Playing a crucial, central role in the running of the show is Mike McKnight, who quite literally knits together the audio, video, lighting and pyrotechnic departments with timecode, so they can perform on time, every time.

At the start of the project, Waters used the Floyd album (and also live recordings from the 1980 shows) as references for which versions would guide the creation of the video content. Tempos and timings varied in some cases, and the final choices informed Mike McKnight and drummer Graham Broad's programming of click tracks, which everyone plays to.

"Graham is the band's engine room, and it's a big responsibility,” says McKnight. "Obviously, the band are playing live, but it calls for a lot of discipline when you're being held down by a click track for the entire evening. Unfortunately, there's no other way to pull off this show, and it can't change because of how the show was built.”

McKnight runs MOTU's Digital Performer 5.13, an integrated digital audio and MIDI sequencing production system that he previously used on tours with Madonna and Mariah Carey.

"It's kind of like Pro Tools but better. The system delivers the metronomic click-track that enables the musicians to play in time with the original music we used in order to build the video imagery.

"I send timecode to video, lighting, pyro and audio, so that everything in the show occurs at precisely the correct time. Their consoles are receiving what my computer sends out to them. I worked for a month figuring all of this out before we got to rehearsals.”

The quality of Trip Khalaf's mix might fool some into thinking that this isn't as live a performance as it actually is. There are, however, some 'live' aspects like Waters 'neo‑Fascist' megaphone delivery on 'Waiting For The Worms', that rely on playback from McKnight's system.

"We tried to make that work for real, but it was too difficult,” says McKnight. "Fortunately, when it comes to the backing vocals, we are blessed with wonderful singers. That's not always the case with some of the R&B tours that I do!

"I have five feeds of music and surround content that I send to FOH and monitors. Along with the click, there are a number of voice cues that I pre‑recorded into the computer to count in impending show events, such as when Roger has to fire a fake machine-gun at the wall — I say, 'Get ready to shoot... one , two, three, four, shoot... stop!'. Obviously, that gun sound is coming from me too, or we'd be in a lot of trouble!”

McKnight's final cue of the night comes when the wall tumbles. "I send out a low‑end signal to the subs that makes the whole room feel like it's shaking and rumbling. It's a manual cue because it can happen at a different time each night.

"The start of the show for me is about 25 ‑minutes before the band walk on stage. That's when I hit 'play' on my computer and start the walk‑in music [classic protest songs from Dylan, Lennon and Sam Cooke], and then the timecode doesn't stop until just before 'Mother', which gives Roger the chance to address the audience. He can ad lib all he likes but there's a certain line he'll include at the end that we both know is my cue to run the timecode again, until the next stop.”

McKnight qualifies as one of the true unsung heroes of the touring world. Word of mouth referrals from him have helped musicians such as Michael Jackson guitarist Orianthi and U2 offstage keyboardist Terry Lawless land their high-profile gigs. But of course it works both ways, too.

"It was Trip who recommended me for this tour, and I'm really glad he did. It's been one of the most rewarding experiences of my career.”

Trip Khalaf: Tour Manager

"Tour management is probably the most thankless task in the world. They're all against you. Developing a feeling of paranoia is perfectly legitimate. Airlines don't give a shit and receptionists at hotels are entirely clueless idiots. Why do I do this? Ah, I get paid more money. It's a wonderful life... why am I complaining?”

These can only be the free‑form deductions of Trip Khalaf, the Hunter S. Thompson of the touring world who, even on a bad day, rivals his boss, Roger Waters, for dry and unforgiving sarcasm. Trip's been putting a great deal of practice into this art form since the tour began.

It was 12 years ago, on the In The Flesh tour that Khalaf began working with Waters as his front-of-house sound engineer, adding the tour manager title for good measure. Then, seven years later, the Pink Floyd co‑founder resurrected The Dark Side Of The Moon for another world tour, the success of which encouraged him to plunder his past once again and 'reinvent' his 1979 rock opera. A big part of Khalaf's responsibility is keeping Roger happy.

"Roger is a different person now to the one I first toured with on In The Flesh in 1999,” says Khalaf. "He hadn't done a big tour for many years up to that point and wasn't very comfortable for a while. Pink Floyd were massive, but to a lot of people they were kind of anonymous, and went out of their way to stay out of the limelight. Only serious fans really knew who they were. But the more he put himself in front of audiences — which, let's be fair, idolise him — the more he mellowed and he's actually changed a lot.

"He's still as professional as he ever was and he's very much a part of the creative process. Every show is recorded and filmed for Roger to review and he is not afraid to call a spade a spade if he sees or hears anything out of place. There's no ambiguity. He'll let you have it straight and that's a good thing, because you're kept on your toes all the time. You'd think that I was safe all that distance from the stage, but I think he may have special powers. The word 'genius' is not applied lightly.”

Published October 2011