Mastering the Noise Pollution
Barry Diament is widely regarded as one of the godfathers of mastering. For Atlantic Records, he was one of the first sound engineers entrusted with a newfangled technology called the compact disc. For a man whose name is synonymous (at least among audiophile geeks) with some of the biggest rock albums of all time (Guns N’ Roses’ Appetite for Destruction, Led Zeppelin’s Physical Graffiti, U2’s October, Bad Company’s Bad Company) his face should be on a few black T-shirts. For AC/DC alone he’s created compact-disc masters for High Voltage, Let There Be Rock, If You Want Blood, Dirty Deeds Done Dirt Cheap, Highway to Hell, Back in Black, For Those About to Rock and Who Made Who.
And mastering is big business. When AC/DC signed to Sony in 2002, the first announcement made by their new record company was that the entire back catalog would be digitally remastered and reissued. Those 2003 reissues have gone on to shift tens of millions of units. The same catalog was put through the mastering laundry again when it was made available on iTunes. From an audio perspective, this constant remastering of remasters of old masters can amount to a whole lot of nothing but, with fans as passionate as AC/DC’s, it’s a license to print money. In the band’s first week on iTunes in the United States in late 2012, there were 50,000 downloads of its albums (15,000 of Back in Black alone) and 700,000 single downloads.
Mastering, unlike producing, is a solo, largely thankless activity; Diament didn’t work with any members of the band on the AC/DC catalog when he was at Atlantic. His job, he says, is to look for “the sonic truth” when he masters an album—rather than “editorialize or beautify the sound”—in order to keep the original recording and the finished master to as much parity as possible. And it’s all about dynamics.
“It is the dynamics that make a record powerful sounding,” he says. “Dynamics are the differences between the loud parts and the quiet—or less loud—parts. Dynamics determine just how much ‘slam’ the listener experiences in the drums, just how much ‘weight’ there is in the attacks of the bass or in the guitar chords and just how much ‘bite’ there is in the lead guitar solo. One of my prime goals in mastering AC/DC’s albums for CD was to preserve 100 percent of the dynamics in the source tapes.”
As was protecting AC/DC’s distinctive “space” in their music. A job that began with Tony Platt in the recording studio.
“I had room mikes up,” explains Platt. “I just controlled how much of each instrument was leaking onto the other instruments’ microphones. So that when you combine them together, it’s what I call ‘acoustic glue.’ It enables the sounds to actually feel like they’re being played in the same place and at the same time, because of course they are. So it just helps to stick it all together. And that only works if you’ve got a band who is capable of playing tracks live—two guitars, bass and drums—and can get it right.”
When the tapes got to Diament, the onus was on him to retain that space rather than augment.
“Space is one of those things that can very easily be diminished, obscured or completely eradicated by too much processing, by compression of dynamics or by a less than optimal signal path in the mastering room. In addition to preserving performance dynamics, space and air are important considerations.”
That focus on preservation included some of the incidental sounds from the recording, such as the drag on Brian Johnson’s cigarette in “Rock and Roll Ain’t Noise Pollution” and Phil Rudd counting down the beat in “Back in Black.”
“When we experience a musical performance, it isn’t just the instruments in isolation that make up what we hear,” he says. “The humans playing the instruments and the space between and around the humans and their instruments are all part of the total experience. If the original recording engineer captured these, I would consider them crucial to the whole.”
Unlike some bands, AC/DC also manages to be powerful without being teeth-shatteringly loud.
“Some artists have mistakenly been led to believe that raising the level encoded on their CD—making the record itself ‘hot’— makes their recording cut through more on the radio. In fact, the opposite is true: radio compressors tend to clamp down even more on this type of record, resulting in rather wimpy sound rather than powerful sound. It would seem many record-company executives also believe people buy records because they are loud. I don’t know about this as I’ve always bought records because I like the music. Neither do I know anyone who ever said, ‘Wow, that record is loud, I’ve just got to get a copy.’
“Making the record itself loud means other aspects of the sound must be compromised. Prime among these are the dynamics—the very place where the slam and power of the recording come from. This is why so many modern masterings have no real energy. In addition, the compressed dynamics lead to a stress response in the listener. No wonder folks aren’t buying as many records as they used to. Joe and Jane Average might not be thinking about it consciously but they know their newer records just aren’t as much fun to listen to as records used to be and they don’t listen to them as many times as they’ve listened to purchases made years ago.
“In contrast, when the dynamics of the recording are preserved, the listener will have to turn up their playback volume control, especially compared to recordings mastered in the past several years. What a difference. They can turn the recordings way up without experiencing the painful quality a ‘hot’ record engenders. And they can experience the full dynamics, the full slam, weight and power of the music in ways those ‘hot’ records just can’t achieve.”
Tristin Norwell, a freelance engineer at Alberts back in the early 1990s who relocated to London to work for Neneh Cherry and Dave Stewart of Eurythmics before becoming a composer in his own right, agrees with Diament.
“The recording purist will always want to capture and reproduce the full width of dynamics of an artist’s performance,” he says. “If you go to a lyrical theater, and you are in a good one, you will hear an actor whisper when they are being coy, and when they shout they will get the message across without it being distorted.
“Recording music is the same. But the broadcast mediums are very different and therefore reproduction tricks vary depending on the message being sent. Tools such as compression, limiting and ‘loudness’ are designed to exacerbate subtlety, not retain it. They are designed for an inattentive audience who might only ever hear music when they’re shopping, so any musical message needs to be rammed down their ears at any given opportunity.
“Back in Black works because it’s a beautiful technical reproduction of a great performance and of the space in which they are doing it. With Johnson’s voice carefully balanced between the air of the room and two great-sounding electric guitars, a drummer and a bass player, all performing with genuine ‘intent,’ it becomes a god-sent ear-candy moment.
“Any less dynamic would soften the message, and any more may send a metalhead to sleep. The point is that the quiet bits are as captivating to its audience as the loud bits. This is what an engineer is talking about when he or she talks about ‘space’—dynamic space. Space that is reproduced by a technical exercise in which we, the listener, get to ‘feel’ a performer.
“Classical music is usually the best example of this for the audio junkie, as it requires massive signal-to-noise ratios for transparent reproduction, but Back in Black comes close to this for the hard- rock junkie.”
For all the audio whizzbangery of the AC/DC catalog, it hasn’t always been so sophisticated. Tony Platt recounts a story that during the production of the Bonfire box set in 1997, George Young was forced to master the AC/DC: Let There Be Rock film soundtrack from old cassettes Platt had lying about. Norwell recalls that before he moved to the UK he was asked by Alberts to archive the entire AC/DC two-inch tape collection.
“I went into Studio 2 one day and found the in-house building maintenance bloke trying to work out why a tape he’d put on the MCI tape machine wasn’t rewinding. I asked what it was, and freaked out when he told me.
“It was an original AC/DC tape. It was so old—and a notoriously bad batch of BASF—that it was dropping metal onto the heads. By the time I got there it was half a centimeter thick. The tape was ruined. Fortunately, it was probably only about two minutes of an old outtake, but I hand-wound it back on and sent it off to be rebaked.”
Rebaking is an archiving process by which the tape is restored temporarily to allow just enough time to transfer it to a new reel.
“Anyway, with a heavy heart I turned down the job. I would have spent six months transferring every recording AC/DC had made to that date. I don’t know who did it in the end. Hopefully not the mentalist bong-head from the workshop cellar.”