"With most types of heavy music, it seems like the goal is to make everything louder than everything else."
That's producer and mixing engineer Kurt Ballou talking about the challenges of working in heavy music. He ought to know: He's recorded and mixed some of your favorite records, including standout releases from Code Orange, Nails, Kvelertak and, of course, his own band, trailblazing metallic hardcore veterans Converge. Operating out of his GodCity Studio in Salem, Massachusetts, Ballou works with all types of music but has become most sought-after in the realms of hardcore and metal.
As such, he's more than familiar with the challenges involved. "There's a density to the music that doesn't necessarily exist in other genres, both in terms of speed — meaning the notes are very close together — and in terms of volume and compression," he says. "The distortion of a guitar amp reduces the dynamic range of the guitar to be very small and essentially a steady signal. So trying to get drums to poke through that steady signal requires really careful use of compressors. But the main thing is that it doesn't allow you to have a ton of interesting nuance to the tone. There's just not a lot of space for that stuff."
All the "interesting nuance" is also part of what sets TIDAL — the digital streaming platform owned in part by hip-hop icon JAY-Z — apart from other DSPs. While most streaming services use compressed data files for playback, TIDAL's offerings include CD-quality lossless tracks and hi-res MQA recordings, which retain more of the subtlety and detail that dedicated audiophiles such as Ballou prize so much.
Those subtleties and details are particularly challenging to capture in metal and hardcore. As Ballou points out, distorted guitars create all kinds of issues when it comes to recording music at the highest fidelity. The down-tuning of guitars — a common practice used by heavy bands of all types in which the pitch of one or more guitar strings is lowered to below standard E tuning — is a major one. "Most other genres don't have down-tuned, deeper-sounding guitars or bass like heavy music does," Ballou says. "Even if you're tuned to standard E, most speakers will not reproduce the fundamental frequency of a bass guitar low E string. But there's overtones above that fundamental frequency that allow our ears to actually fill in the blanks. So engineers use a variety of techniques to exaggerate the upper overtones of the bass frequencies."
What Ballou calls "bass management" is a big part of heavy music that isn't as much of a concern in many genres outside of, say, electronic music. "Bass is obviously what so much of electronic music is all about, but electronic music is designed to be played in places with insane sound systems," he explains. "Heavy music isn't really designed to do that, so the way we treat low frequencies is definitely different, but I think equal attention is paid to the lows in both genres."
When Ballou is finished mixing a record, he sends it to a mastering engineer as a series of lossless audio files — usually WAV files. The term "lossless" applies to a digital audio file that's not compressed. "What gets confusing is that there's two completely different types of compression at work within audio," Ballou explains. "Audio compression is a rack unit or a plug-in that changes the dynamic range of a signal. Data compression is like an mp3 — a file that has been crunched into a smaller, more compact file that can be streamed easier. They're two entirely different things that just happen to share the same name."
An easy way to think of data compression is in terms of the ubiquitous ZIP file — a compressed version of a much larger file (or files) that makes it easier to send over the Internet. You see this kind of compression all the time with large photo files. "You can make a lot of analogies between photos and audio," Ballou says. "Think about pixels: If the final format of a photo is a small, 150-dpi thumbnail on a website, would the graphic designer wanna work on it at 150-dpi resolution? No, they're gonna work on it big — which future-proofs it — and then dumb it down at the end." TIDAL uses the big, future-proofed audio files.
Regardless of the final playback system, though, Ballou's job remains the same. "The thing that we as engineers can do is try to preserve as much quality in the music for as long as possible," he says. "If our mixes are of the utmost quality, then as future playback systems come along and 5G becomes more common and streaming gets better and more lossless, the work that we do today will benefit 10 or 20 years down the line as those services get better."
Right now, TIDAL is offering a free 60-day HiFi trial subscription to new users, allowing the ability to stream over 60 million losslessly compressed tracks.