A hit movie about the world’s greatest rock band turns conventional ideas of audio restoration on their head.
“In the early stages of making the film, we met with extraordinary resistance to the concept of playing whole songs,” says Bernard MacMahon. “People were just like, ‘No‑one’s going to be interested in that!’ But if you think that the story of this band is worth you sitting in a theatre for two hours, then I believe you’ve goddamn got to play a whole lot of that music. And if that isn’t a total thrill for the audience, why are you even doing this band in the first place?”
Not only does Becoming Led Zeppelin include full songs, but the team behind the movie also flew in the face of industry convention in their approach to sourcing and preparing this music. Director MacMahon, sound supervisor Nick Bergh, writer, producer and music supervisor Allison McGourty and editor Dan Gitlin had the full cooperation of the band and Atlantic Records. They could therefore have accessed the master tapes, or any of the numerous digital remasters that have been released over the years. Instead, they used the original vinyl records.
“We made a very conscious choice to go with the discs,” says MacMahon, “and the reason is that the tape is often so different from what the public heard. Even if the master tapes survived of all the studio recordings, which a number don’t, they were always made with the mind that they were going to be significantly altered in bringing them to the public on a piece of plastic. The production master was altered from the quarter‑inch that was made in the studio, then that production master was enormously goosed at the cutting stage by a Bob Ludwig.
“What the public heard on their record players is not what you would have heard played back in the studio. So the truest thing is for you to hear the ultimate thing that millions of people bought, in the truest possible way. That’s the philosophy of the film.”
Pressing Matters
The first step was, therefore, to obtain the best possible vinyl copies of everything. This was not as simple as it might appear, given the complex nature of record manufacture in the ’60s and ’70s. Taking Led Zeppelin’s 1969 debut album as an example, “There were many different early pressings of Led Zeppelin I that differ widely in sound quality,” says Nick. “This wide disparity seemed to be largely due to record azimuth errors in the original tape and the various ways mastering engineers were correcting for it, or not correcting for it.”
Director Bernard MacMahon (left) and sound supervisor Nick Bergh (right) review Nick’s transfer of Led Zeppelin I at Endpoint Audio Labs.Photo: Allison McGourty
“Atlantic were using four pressing plants,” continues Bernard, “and on album one, each of those plants had different lacquer cuts made. And the white label test pressings that are very desirable by collectors, that’s another cut as well. And each cutting engineer that’s making the lacquers for those different plants is maybe doing two or three or four lacquers. And each of those might have minor differences, as anything would in the real world. Each of those is different. On the RCA pressing, the channels are the wrong way around! The fans generally seem to think that’s a different mix. It’s not, it just obviously doesn’t sound the same as what they’re familiar with.
“So what was amazing with Led Zeppelin I is that the pressings are radically different in terms of sound and quality. And the best was from George Piros, a classical cutting engineer who came from Mercury [Records]. He didn’t like rock music at all, but he was essentially just getting what was on that tape on the record, and that’s why his is the best.”
So different are the various pressings, in fact, that MacMahon believes this was a factor in the dire press reviews of Zeppelin’s debut album: the white label copies that were sent to journalists were from one of the worst cuts.
The First Cut Is The Loudest
The film concludes with the triumphant release of Zeppelin’s second album, a disc which threw up different but equally confusing choices for the team. “When Led Zeppelin II was completed, it was sent to Bob Ludwig to cut,” reports MacMahon. “Unlike on album one, Ludwig cut all the lacquers for North America. And that record sounds absolutely amazing, and it’s incredibly loud.
“And, as you know, volume on a record is created by the needle moving rapidly and dramatically in the groove — but the apocryphal story is that [Atlantic Records co‑founder and President] Ahmet Ertegun’s daughter had a white label pressing of the record and was playing it on a cheap kids’ turntable and the record was skipping. This was a problem with super‑loud records: they would skip because the needle on a bad hi‑fi would be jumping so much it would bounce out of the grooves.
Eddie Kramer (left) and Jimmy Page mixing Led Zeppelin II. Rather than return to the masters or remasters, the film‑makers chose Bob Ludwig’s original vinyl cut as the definitive representation of the album.Photo: Ron Raffaelli
“So that record was recut. The first 200,000 or whatever copies were this amazing version, and then everything else that was sold subsequently was this much more dialled‑back master with a much less dramatic cut. When you hear the Ludwig cut, the music has this unbelievable excitement to it. It sounds so good that people will now pay upwards of three and a half, four thousand dollars for pristine copies, even though it’s not technically a rare record. Unlike on the first album, all the media would have heard that version. The white labels were all that version, to my knowledge. And that record had a seismic impact in America.”
MacMahon: "When you hear the Ludwig cut, the music has this unbelievable excitement to it. It sounds so good that people will now pay upwards of three and a half, four thousand dollars for pristine copies, even though it’s not technically a rare record."
Transfer Windows
Once the best version of each release had been identified, the next challenge was to track down the best possible copy of that version: ideally, one that has never been played.
“Even a single play can instantly damage the record,” warns Nick. “The louder the cut, the more the stylus is moving in the groove. If you played it with less than ideal equipment, especially back then, the stylus can’t move fast enough. So essentially it’s gouging the groove as it’s being thrown around in the groove.”
What’s more, there can still be problems even with unplayed copies of the best pressings. “Atlantic were notorious for using shoddy material in their vinyl,” says Bernard, “putting a lot of filler and junk in. And so I was buying sealed copies that were expensive even before the market had exploded, in the hope that there was a Ludwig in there. A couple of times, I got lucky, and this one happened to be an unusually quiet press — a nice puck, you know, with very little detritus in it.”
The results more than justify Bernard and Nick’s unusual approach. Even the older, pre‑Zeppelin mono recordings in the movie sound fantastic, and it’s tempting to imagine that lots of digital post‑processing must have been involved. Not so.
“There is no traditional restoration processing,” says Nick. “There is no broadband denoise anywhere in this film.” His philosophy, rather, is “the best restoration is no restoration”. The goal is to achieve the best possible transfer from the best possible version of the source, and then to leave it alone. “I couldn’t imagine mixing a film like this without personally doing every single transfer, because that’s really where the sound gets locked in. That’s where the cake is being baked. Everything else is just kind of frosting.
Nick Bergh: "One of the biggest problems with mono material is low expectations, when really the mono material can sound incredible. The challenge is getting that incredible sound translated to a newer system."
“One of the biggest problems with mono material is low expectations, when really the mono material can sound incredible. The challenge is getting that incredible sound translated to a newer system. It’s primarily a translation issue more than anything else, because if you play mono material on an original great mono system, it can still be incredibly compelling.
“When people hear archival audio these days, it is typically multiple generations away from the source, or it’s gone through processing, and so It’s often hard to explain that ‘This stuff can sound fantastic — you just haven’t heard it correctly yet.’ Trying to just get that sound onto the screen is always the challenge, because any time you put it through processing or mess with it, it’s gonna start to chip away at that magical sound. Broadband denoising is essentially like taking your sound and dipping it into a piranha tank!”
To The End
The all‑important transfer process took place at Nick’s remarkable Endpoint Audio Labs facility, a working museum of film sound. Amongst many other fascinating items, Endpoint hosts Nick’s restoration of the gravity‑fed lathe that was used by the likes of Ralph Peer to cut classic blues records in the ’30s, and which featured prominently in the film project that originally brought MacMahon and Bergh together. American Epic unearthed vast amounts of previously unseen archive material relating to early blues, country and roots music, and was instrumental in persuading the surviving members of Led Zeppelin to place their faith in MacMahon.
Left to right: editor Dan Gitlin, sound supervisor Nick Bergh and director Bernard MacMahon at Endpoint Audio Labs. The gravity‑fed lathe restored by Nick and featured in American Epic is visible against the wall to the left, along with part of its associated rack of power amplifiers.Photo: Allison McGourty
“Even though those records are very old, they’re very demanding as far as fidelity goes,” insists Nick Bergh of the American Epic material. “Because there is no limiter, there’s no negative feedback and there are very fast transients, those old blues records from the ’30s are very demanding to get everything out of them.”
Following painstaking cleaning, Bergh’s transfer process involves an EMT 927 turntable with an SME arm, and custom electronics by Vladimir Lamb, feeding a Lavry Gold A‑D converter. “It’s not just playing the record through all the way through,” he explains. “With a swinging tone arm, the arm is only right in two places on the record, and it is set so it is averaged across the whole side. For this film, because time doesn’t matter, I can adjust it perfectly for one track and then adjust it again for the next track. Small things like that add up to get a great sound out of it.
A pristine copy of Led Zeppelin I vinyl album on Nick Bergh’s EMT 927 turntable.Photo: Nick Bergh
“Something we experienced in American Epic was that it’s amazing how delicate a great transfer is, and how much it doesn’t ever want to be touched after that. Any EQ, anything you touch it with, you hear it. Even if the processing is helping in some ways, it seems to yell out: ‘Hey, you did something to this!’”
Out Of The Archive
In most cases, no digital post‑processing was applied at all, not even basic equalisation. The audio from Led Zeppelin I and II did not touch a single plug‑in except for the panner. Any surface noise was painstakingly removed by manual waveform editing rather than plug‑ins. (This manual declicking was undertaken by Peter Henderson, perhaps better known as co‑producer of Supertramp’s Breakfast In America.)
However, not all of the audio in Becoming Led Zeppelin originated on vinyl. The movie includes numerous filmed live performances by Zeppelin and other acts, from many sources. These covered an amazing range of audio media that one may not expect for rock & roll, such as 78rpm records, 16mm optical, 35mm optical, 16mm mag, 35mm mag, one‑inch and two‑inch video, 45rpm singles, lacquer discs, and various more typical tape formats. Once again, the key to achieving the best possible sound quality was to have Nick Bergh personally make the transfers from the original sources — but when the original sources were priceless archival artefacts, this introduced a whole new level of difficulty.
Archive material was sourced and freshly transferred from an incredible variety of original formats. Clockwise from top left: 16mm negative of the 1969 film Supershow, with Zeppelin performing ‘Dazed And Confused’; the Danish two‑inch PAL SECAM tape from which ‘Communication Breakdown’ was taken; the crucial quarter‑inch tape of John Bonham and Robert Plant being interviewed for Australian radio, seen through a magnetic viewer at Endpoint Audio Labs; and 35mm reel from the groundbreaking 1964 concert film TAMI Show, shot in Bill Sargent’s pioneering high‑definition Electronovision format.
“From my point of view,” says Bernard, “the number one thing is getting the material into Endpoint with Nick, so he’s doing the transfer and we have the master ourselves. And the most difficult thing in doing this film was: how do you do that? Because it is normally against all archival policy to have masters travelling around the world to some facility 5000 miles away. This is normally just not done.
“And in the early edits of the film, we planned to have an evocation of the Hindenburg’s flight over to New Jersey and its explosion [as featured on the cover of Led Zeppelin I]. That is, obviously, one of the most iconic historical pieces of archive ever. And we wanted to use some of Herbert Morrison’s legendary commentary. So Allison spent a long time dealing with the National Archives, and she persuaded the National Archives to bring out to Endpoint the original lacquers that Herbert Morrison cut in 1937.
“When Nick transferred them, the fidelity of the sound of his voice was shockingly improved. It was mind‑bogglingly better. The lacquer had been damaged where the airship had exploded, and it would normally have been unplayable, but Nick was able to navigate the disc, so for the first time ever you could actually hear the real explosion of the craft, instead of the sound effect that was used on the newsreel. You could also hear the screaming of the people on the ground, and coming out of the craft.
“One of our archive editors said, ‘This is the most powerful introduction I’ve ever seen to any movie.’ But because of how shocking this audio was, it was literally horrifying to watch and listen to. And you couldn’t begin a film about Led Zeppelin after two minutes of that — but that’s the power of sound.”
“That disc had only been played a few times, maybe three times or so,” says Nick. “But unfortunately it was in the era of very gnarly heavy pickups. And any playback on a lacquer severely damages it. A lacquer is essentially just thick paint on aluminium. So that’s a really interesting example, where if no‑one had played that thing in the ’30s, the audio would be essentially contemporary‑sounding. That’s the quality of that audio on the record. But unfortunately it was severely damaged when they even played it a couple times on NBC. The particular microphone and electronics they were using was really high fidelity, and it’s still very compelling.”
Detective Work
Although the Herbert Morrison material ultimately proved too strong a meat for a music documentary, it helped MacMahon and McGourty persuade other archives to trust them. Crucially, this meant they were able to access a previously unheard radio interview with drummer John Bonham. Led Zeppelin never did many interviews, and even when they did, Bonham tended not to talk, so including his voice was one of the film‑makers’ biggest challenges. Bernard MacMahon takes up the story. “Sam Rapallo, who runs a Led Zeppelin website, turned me on to an obscure bootleg with this pretty crummy‑sounding multi‑generational copy of an interview with Robert Plant and John Bonham. But when Nick and I listened to it, we could hear straight away this had originally been recorded to a quarter‑inch tape. I could also tell it was a radio journalist, because he was not talking over them and he was giving them space. All we could hear on the bit that was on this bootleg was that it was an Australian journalist.
“Fortunately, the University of Canberra had done an American Epic festival, and I called the guy that had organised it, and he eventually identified the voice and what radio station it was. We went to the radio station and said ‘Do you have the original tape?’ And they looked for a while and they didn’t have it. And then I said, ‘Have you ever sent any of your tapes anywhere?’ He said, ‘Well, we have bequeathed some of our old tapes to an archive.’ So I called them back and they looked through the archive and said, ‘No, we don’t have it.’
“And then I remembered from American Epic that a lot of the big archives will often have pallets of recordings that they haven’t had time to catalogue. So I said, ‘Do you have any uncatalogued tapes?’ And they literally said ‘Thousands!’ And because we’d been helpful with American Epic and they were really nice, they started to look at it. Months later, I got a phone call near midnight out here in LA and it was this guy Sean from the library. ‘I think I’ve got it. Go to your computer.’ And he’d sent an MP3 and there it was, the tape.
“After that we got the transfer of the whole thing in 24/96, and Nick went, ‘We need to do this ourselves.’ So I called them back and I said, ‘National Archives... Herbert Morrison...’ And, incredibly, they sent it to us, and we were able to transfer it, and that’s what you hear.”
Led Zeppelin: The Musical?
As Hollywood’s leading specialist in vintage film sound, Nick Bergh has been responsible for preserving many classic movies, including great musicals like Oklahoma! Unlikely as it sounds, this fed directly into the making of Becoming Led Zeppelin. For one thing, it inspired the team to go against modern convention by avoiding any processing that would homogenise the sound of dialogue and music, or of recordings from different eras.
Cleaning the rarest disc featured in the movie, a 1968 lacquer recorded by Robert Plant and John Bonham’s pre‑Zeppelin group Band Of Joy.Photo: Michael Rice
“One of the things I like about keeping archival music so original is the recordings all sound a little different,” says Nick, “because they’re all done in different studios and with different gear. As soon as we start putting the same EQ and the same limiter on these things, some of that goes away.
“One of the most striking things about working on the old classic musical films from the 1950s and ’60s was how much care was typically taken with music fidelity. The musical numbers were often like structural pillars that everything else built up against. The aesthetic with musicals has changed a bit now, where the mics and fidelity are intentionally chosen so they flow better with the production dialogue scenes. They can still sound good this way, but it is not like Julie Andrews singing through a U47 with minor tube compression and essentially nothing else.”
The influence of classic musicals also extended into the structure of the film itself. “The film is constructed like a musical,” says Bernard. “All the songs are sequenced and chosen in terms of what’s being sung about relating to what’s going on. The first time you hear ‘Communication Breakdown’, they’re playing to an unreceptive European audience that are putting their fingers in their ears. As they’re going off to try and get a deal in America with Atlantic, we’re playing, ‘Your Time Is Gonna Come’. And we’re using the chorus of that song as a narrative device. Every single song is used to advance the story. We’re using musical techniques that we learned from being in here and hearing these great musicals being played back.”
It’s a highly effective device, allowing the viewer to feel caught up in and swept away by the band’s growing success. “That’s a construct of the pieces of music and the order that they’re placed in, to create that effect that you are going further and further forward. You start with this very simple skiffle sound, and Little Richard in this unbelievably powerful mono, and you end up with this enormously expansive sound with the the whole drum kit panned all the way across the picture. You go on the sonic journey that the world took over those two decades.”
Just a few weeks after release, Becoming Led Zeppelinis already the most successful IMAX music movie of all time...
Just a few weeks after release, Becoming Led Zeppelin is already the most successful IMAX music movie of all time, to the point where demand has forced Sony Pictures to bring it back for a second IMAX run across America. And fans, many of whom are viewing it for the third or fourth time, would agree wholeheartedly with MacMahon and Bergh that one factor above all is fundamental to its success: the sound.