Interview | Engineer Mixing / Production By Sam Inglis

The mastering engineer's role is changing as artists explore new formats. And as Björk and Mandy Parnell discovered, what works for the iPad might not work on CD...

Mastering is supposed to be the simple part of making records, right? You bring your stereo mixes along to someone with a fresh pair of ears, a nice monitoring system and a bunch of gold discs on the wall. He or she checks that there's nothing wrong with your files, runs them through some specialist equipment you can't afford in order to make them sound 'finished' and then generates production masters. Simple.

Simple, that is, unless you're Björk, and your latest album is Biophilia, the 'world's first app album', released in conjunction with Apple. All of Biophilia's 10 tracks are being issued as apps for iOS devices in collaboration with Scott Snibbe, an interactive artist who combines his visuals with images from National Geographic and narration by David Attenborough. They explore a variety of music- and science‑based themes, forming a multimedia collection "encompassing music, apps, Internet, installations and live shows”.

Björk debuted songs from the album during a series of performances at the Manchester International Festival before it materialised in conventional music formats on CD, vinyl and MP3. By this time, a few months had elapsed since the music had originally been 'finished', and having performed the songs live, Björk decided there was more she could bring to the project. She asked long‑term collaborator Leila Arab to help with some sound sculpting, and Leila suggested she should consult mastering engineer Mandy Parnell.

"The idea of the original mixes for the apps,” explains Mandy, "is that when the song are played through the iPad speakers, you hear the mid and top end of the mixes, and when you plug your headphones in, this whole other dimension with all the sub‑bass comes through. The app album was deliberately mixed with this in mind, so when you listened to the original master, it was very prominent in the sub‑bass area and the top end, but slightly lacking in the upper bass and lower‑mid area. When Björk received her audio CD back from mastering without the visuals and the experience of hearing through headphones, she was not so convinced of the mastering for the CD. It really works amazingly for the apps, but she felt the album needed to be fuller. At the point where she had received the references for the CD, Björk had already performed a month's residency in Manchester playing 10 incredible shows, so she had a completely different emotional and sonic connection with the album. The music had morphed into a different experience in the time that had passed, so after finishing the shows in Manchester she decided to go back into the studio with Leila Arab and rework the album.”

Mandy Parnell's involvement in the project escalated rapidly. "It started off with me receiving a call from One Little Indian [Björk's label] saying 'She's not happy with her vinyl, can you re‑cut it?' Then 'She's not happy with the album, can you re‑master the album?' Then 'Actually… we've heard that you sometimes get involved with taking a mobile rig to another studio and mastering there, could you do this for us? Can you fly out to Iceland?'”

This Mandy promptly did, to be greeted with yet another surprise. Curver Thoroddsen, one of Björk's assistant engineers, opened up the files, and they were all mix sessions. There were no stereo bounces of the tracks. "I didn't know that I was going to be presented with stems. I thought I was going to be working on the stereo masters!”

Mandy was not aware of the changes Björk had made to the mixes at this point, and in case this wasn't stressful enough, she was working against a looming and immovable deadline, with an unfamiliar setup, in a studio she'd never seen or heard before. "I went into Addi 800's studio Ö&Ö. He's worked with artists like Björk and Sigur Ros numerous times before, and he's one of the top mixing guys in Iceland. We went into his studio to get set up, before I would meet Björk and go through the album with her.

"I had taken my rig with me, including a Prism Sound Orpheus — I used this and SADiE as my mastering system. Prism and SADiE is my normal system and it's great for me now that SADiE is native, it makes my mobile rig more versatile as I can run it from my laptop. My signal flow was from Pro Tools into a Thermionic Culture Phoenix compressor, a rare Inward Connections EQ, a Crane Song STC8, then my Orpheus; I used the limiter of the TC System 6000. Addi's studio has the Barefoot MM27 monitors with a Genelec sub and a Dangerous monitor controller. I had taken my Benchmark D‑A as well, and I said I'd rather run the Barefoot MM27s from the Benchmark because I know the sound of it better than the Dangerous monitor controller. We set up the subwoofer with the Dangerous monitor controller to give us the option of punching it in and out during the mastering to check the really low subs. We realigned Addi's Barefoots listening to lots of references while tweaking, so that they felt closer to my listening environment in my studio. The Barefoots were incredible to work with.”

"I sat with Björk for many hours playing back the mixes, talking about the album, the concept, looking at the apps, hearing about the incredible instruments that had been built especially for the project. I made notes and markers for each song. We listened to each song, played with the apps and talked at length while Björk was giving me an overview of the whole concept of the album. Björk works on a very emotional level: she talks about what the intention of each song is, and what feelings it is going to conjure up in the listener. I said 'Let me work on one track tonight, and I'll send you a couple of different mastered versions to pick from. Give me some feedback and we'll get going on the rest of the album.' I decided to work on 'Crystalline' and spent a few hours trying different things, exploring the different textures and depths I could get from the mix.

"Björk came back the next day with the version she had chosen, and then it was all systems go. All of the mixes had elements changed; for instance, on one song Björk had decided to change some of the choir arrangements and use some different takes of the recording. Björk and Curver were editing that in another room while I was mastering in Addi's room. She had also decided to use the live version of 'Solstice' rather than the recorded one, as she preferred the way the song had grown out from the live performances.”

This would have been enough of a challenge had Mandy been asked to work with conventional stereo masters, but instead she was confronted with large Pro Tools sessions containing stems — and not just a few of them. "Most of the time when I am sent stems to master from, I am given the instrumental, main vocals and backing vocals. I would adjust the balance of the vocals with the mix during mastering. Working from stems is a whole other way of thinking for me, it opens doors to endless possibilities that I would not have in a stereo mix. Björk's project was presented to me in a Pro Tools session with the mix ready to roll, or so I thought — as I started to go through each track I realised I could do fine adjustments to create the space in the mix before going into the mastering chain.

'I would be given the choir vocals for instance, with many different edit sections that needed re‑comping. I would have the drums, maybe on more than one stereo group, there might be a few different groups of Björk's vocals, as well as other beats, various instruments on other groups and sound effects. Some of them you'd open and there'd be a page full of stereo stems, groups and tracks.”

Despite being unfamiliar with Pro Tools as a mastering system, Mandy, with the help of Björk's assistants, ended up using its automation and software EQ quite extensively to balance the mixes prior to sending the signal through her analogue mastering chain. "I had the chance to rebalance the mixes and process the separate tracks with EQ and compression, as well as the stereo mix bus. I really enjoyed working with some of the spatial effects on the separate stems inside Pro Tools, working to open up the choir in the stereo field, and being able to EQ them separately. This meant that the mastering side was just compression and a tiny bit of EQ: rather than trying to find that space in a stereo mix, I could create it before the mastering. It was great to have that flexibility. I have been working more like this recently — for instance, with Leila Arab's album she brought her rig to my studio and did the final tweaks to the mixes there to get the sound and space she was looking for while monitoring through my mastering chain.

"With something so complex, that has got so many layers of sounds, having access to the stems as a mastering engineer can allow you to get more space out of the mix. I can get it sounding wider and I can achieve more separation this way. It's really about balance and pulling the vocal out. The amounts we're talking about would not really be a lot in a mixing situation. The most might be 0.5 of a dB, while a lot of the time it could be 0.2 or 0.3. On one track, Curver, who sat behind me, said 'I can't believe that's all you've done, and it's made such a big difference.' It's just about approaching the mixes with a mastering ear. I'm not a mix engineer, I'm a mastering engineer, and everything I am looking for is about separation in the sound and the balance of the mix.”

After much effort and fun, Mandy managed to deliver an album that Björk was completely happy with, before the deadline — and one that was radically different from its original incarnation in many places. Mandy was then able to return to her Black Saloon Studios in London, her work done… or so you'd think. In fact, the orchestration of delivering masters for all the different formats, record labels and territories involved kept her busy for another few days.

"We spent 27 hours running production parts for all the different territories. I don't think people realise how much work is involved for an artist of this calibre to deliver an album, let alone what Björk has done with this project. Not only is there the commercial CD, there are also deluxe versions for box sets and vinyl, as well as bonus tracks for different territories.”

Alas, one thing that the mastering engineer has no control over at this moment is the conversion of music into lossy formats for online distribution. "It's horrible,” says Mandy. "What happens a lot of the time is that there's someone in a back room who does the conversions after it leaves the mastering suite, and every platform wants a different codec, be it iTunes, Amazon or CD Baby. The record companies are being charged a nominal fee for this transfer by companies who are not employing trained audio engineers. There is no quality control for what the different codecs are doing to the audio; the record companies would not pay our fees as mastering engineers to check this, unfortunately. Years ago when we would cut vinyl records, the mastering engineer who cut the vinyl would always get a test pressing back to check the quality and the audio. We would be asked to approve the quality before it went into production. Now, once it leaves the mastering studio as files, DDP or CD, we do not know how it is transferred. We, as mastering engineers around the world, have to take back control of the final QC.”

It's a situation that neither Mandy Parnell nor her artists are happy with, but it doesn't mean that quality mixing or mastering have become irrelevant. "With Leila [Arab]'s album, after we mastered everything, but before we finally signed off, we actually transferred everything onto a phone to check it. We were listening to see if the integrity and intention were still there, checking for if you're losing the important elements of the song. The well‑produced, well‑mixed, well‑mastered tracks will still cut through on a phone speaker.”