My Life as a Mastering Engineer


01Here are some rambling reflections on my life as a mastering engineer…

Off and on, I’ve been an audio engineer since I was a teenager. But I started mastering seriously this year, and I now have quite a few projects under my belt.

I thought it would be interesting to share some of my thoughts at this fairly early stage of what is a fascinating journey.

First, what are the biggest problems I find myself dealing with in the music that comes across my doorstep?

First and foremost is probably harsh midrange. This is an especially thorny problem because a lot of artists hear their music’s “raw energy” as living in the midrange, and they may feel they’re missing something when I take steps to lessen the harshness that typically focuses around 3,000 hertz. Sometimes, I feel, artists have been listening to their own music for so long that they often lose perspective on harsh midrange. I want their fans to be able to turn the music up and “jam it” without hurting their ears. I also want every song—even punk songs!—to be listenable. A jagged, uneven midrange makes music hard to listen to, and impossible to turn up! Sometimes there’s harshness in the sibilance range—where singers’ esses dwell. I will typically try to “de-ess” a mix when this happens, but it’s better if the mix engineer does it! This leaves my hands less tied.

Second is that songs often arrive already mastered. Artists are commonly—almost always, actually—strapping compressors and eqs across their master output buses. And they’re not just adding a little touch of compression and eq. They’re being very aggressive! More aggressive than I would, usually. Songs can arrive already squashed to death and brittle on the top end. So I sometimes find myself trying to “unmaster” songs a little, to breathe a little life back into them. There’s only so much I can do in this case! I find myself using less compression than I ever imagined I’d use. When people ask what mastering is, the short answer is “eq and compression,” but I compress mixes less than half the time. They’re usually already compressed, and I usually think adding compression harms the final product. I try compression all the time! But more than half the time, I decide it’s not helping.

Third is an overabundance of lower midrange, or upper bass. I find myself constantly trying to “shift the bass energy” toward lower frequencies, between 50 and 100 hertz, and away from the range between 140 and 250 hertz. Whereas artists tend to be a little unaware of harshness in their midrange, they seem quite well aware of this problem, and frequently ask me to tighten their bass, while “still leaving the bass round.”

Fourth is “too much crispness.” I think many amateur engineers are afraid that, if they ever use an equalizer to cut high end, they’ll dull their music. So we engineers are always “adding air” to try to make our recordings sound “more open.” But actually, we end up making them sound crisp and, well, cheap and “digital.” This problem is pretty easy to handle, though. You just have to be willing to turn DOWN some of that high frequency! That takes guts, and you have to be very careful about which songs you do this to, but it can really warm things up.

I find that one of the myths I believed in—but which I now realize is not true—is that you always want a song to get brighter in mastering. I probably do something OTHER than brighten a song about half the time.



I am finding that I love doing this job. What do I love about mastering? I love the variety of people and music I get to work with. Whereas producing bands, and mixing bands, you work with a single artist for weeks at a time, in mastering you work with each artist for a day, or a few days. I absolutely love musicians. The variety means this job never gets old.

A few other observations: Mastering is a job of constant compromise. Whenever I make a change to a mix, it’s usually aimed at correcting some part of the mix that I perceive to be slightly problematic. But it can affect other aspects of the mix that may not be problematic!

One of the most common places this occurs is in the lower midrange. It’s extremely common for a mix to arrive at my desk with too much lower midrange (180 hertz, give or take a few) in the bass guitar, but with thin, edgy vocals. This is a huge problem, because the fundamental frequencies of vocals can reach down to 180 hertz and below—so if I simply use an eq to take out low midrange, I may get rid of some of the tubbiness of the bass guitar, but at a cost to the beauty of the vocals—which could possibly use a little extra lower midrange themselves!

Destroying the beauty of the lead vocal is just about the worst thing I can do as a mastering engineer. “Do no harm” is probably a good first principle of mastering, and the lead vocal is usually the most precious component of a mix.

Wrestling with this tension between too much lower midrange in the bass guitar and too little of it in the vocals sometimes seems like it occupies half my time!

One way to make sure this doesn’t happen to your mix is to send your mastering engineer stems—such as one mix of the entire song without lead vocals, and one mix that contains only the lead vocals the their effects. Then, I can master the two things separately, dealing with any tubbiness in the track without affecting the warmth of the lead vocal.

Another approach is, when mixing, to make sure you’ve got enough warm lower midrange in your vocal. I think many amateur mixers enjoy a vocal that “cuts through,” but in mixing, I’d recommend going for balance with a vocal rather than “cutting through,” and then, if you like a big bottom, let your bass guitar’s energy find its focus below 100 hertz rather than around 180 hertz.

These days people are listening to a lot of music in cars, and cars seem to resonate around 180 hertz. Amateur mixes often sound a little tubby there, so if you drain your bass guitar of energy in that range, I won’t have to play tug-of-war between the bass and the vocal when it comes across my desk.

I generally think I take a very conservative approach to mastering. I don’t like radically changing an artist’s work. And I never, ever want anyone to hear artifacts of my work. Nobody should say, “Wow, the mastering engineer really cranked this or that knob.” It should sound natural, and listenable, and beautiful, no matter the style. I have a short checklist of things I try to make sure I do when I master:

First, I try to get the bass right. If it’s tubby and sounds woofy in an enclosed space like a car, it’s going to be annoying to the artist (and their listeners). I know, because I’ve gotten back product from mastering engineers multiple times, and they have often left my bass too tubby! I’m actually amazed how little attention other mastering engineers pay to this. They’re listening on beautiful, pristine speakers that don’t reveal this problem. My own mastering speakers make it hard to hear an overabundance of lower midrange, but we artists know this problem exists! I think the elite mix engineers are usually dealing with this before it reaches the mastering desk. This may be why tubbiness is seldom a problem with big-budget product. But with amateur product, it’s a frequent problem, so I work hard to get the bass right.

Second, I try to make sure the vocal sounds great. If it already sounds great before I begin, it’s my job to preserve that, no matter what other changes I make. If it doesn’t sound great (usually it’s too edgy and crisp), I try to warm it up.

Third, I try to make the music sound simultaneously exciting and energetic, and yet beautiful and pleasant in the midrange and upper midrange. If it’s harsh and unpleasant to listen to, I haven’t done my job—but if it’s dull and lifeless, I’ve also failed. These two goals live in constant tension with each other, but I have my methods!

Fourth, I try not to leave an obvious footprint. It has to sound natural, and if you can hear evidence that I’ve been poking around inside your song, I’ve failed. I’d rather music sound harsh than sound overprocessed.

Finally, on multi-song projects I try to make sure the different songs on an album hang together, while allowing each to retain its own personality. I don’t try to completely match the frequency profile of every last song on an album, as this would force me to deliberately make some songs sound worse, but I try to help them “live together.”

I have lots of other things I do, but these are the major items on my checklist!

OK, so I have to get back to work, believe it or not. I have more mastering to do!

Cozi Zuehlsdorff


cozi-zuehlsdorff-song-aug-13-2014So this is an unsolicited music review. I’m reviewing an album because I want to share it with you, and it’s hard to imagine you’ll discover it any other way.

Sometimes you discover good music in the most strange ways, and as a parent of two young girls (5 and 7), I “discover” a lot of music through them. Much of it is music that I would never listen to of my own choice (The Wiggles, The Fresh Beat Band—made-for-TV bands that exist for kids and, while I don’t think either is bad on its own terms, I never choose to listen to it by myself), but some of it is a cut above that, and I might even choose to listen to a song or two. For example, the kids’ cartoon Sofia the First, on the Disney Channel, has a first-rate music director who writes high quality pop songs for the characters to sing. The actress who plays Sofia has a nice voice, and there are Sofia albums you can download that sound terrific and are a pleasure to listen to—if you don’t mind subject matter that appeals to 7-year-old girls.

But that’s not what I’m recommending today.

A little story: my kids saw Dolphin Tale II, the second movie about Winter, the Dolphin who lost her tail and learned to swim with a prosthetic tail, earlier this year. My then-4-year-old developed an obsession with dolphins, and for her fifth birthday, we took her to the Clearwater Marine Aquarium to meet the real Winter.

One of the movie’s main characters is a roughly 15-year-old character named Hazel who helps her dad, the fictional head veterinarian at the Clearwater Marine Aquarium, look after the wildlife there. Of course, my daughters loved Hazel from the movie.

Well while we were at the aquarium last month, the aquarium’s gift shop was selling a CD, Originals, made by Cozi Zuehlsdorff, the now-16-year-old girl who plays Hazel. I bought it for my girls, and also just out of my own curiosity. I wanted to hear what kind of songs this young actress would write, and what kind of voice she has. I confess: I expected the album to be pretty bad. Another young actress who thinks she can sing? And write? The songs would surely be immature and boring, both lyrically and musically, and the vocals would surely be heavily auto-tuned. The production would be semi-pro at best, I figured.

The prejudice against an album from a cute young actress in a wholesome movie is strong, and I suspect Cozi will be sailing against a bit of a headwind to be taken seriously as a musician. (Her impressive classical piano playing on this record should knock that idea down, however, and perhaps her being somewhat famous for the Dolphin Tale movies will counteract any prejudicial critical tendencies.)

Boy was my prejudice wrong. Thanks to my 5- and 7-year-olds for making me give this album a real chance—as in, at least 3 listens. For that’s how long it takes to really know whether you like something.

And this 7-song collection is flat-out terrific, with intelligent lyrics (though written with themes that would appeal to a younger crowd), a vocalist who is doing way more interesting, and different, things than the Katie Perrys and the Miley Cyruses of our time, and, musically—both harmonically and melodically—this is shockingly sophisticated pop music.

Let’s be clear: this is pop music, and it’s written with a younger audience in mind. If, as an intelligent listener, understated indie-rock irony is the only flavor you like (and you know who you are), you’re not going to hear any difference between this record and the latest offering by Taylor Swift. You’re going to listen for 30 seconds and think you know what it’s all about. You will be wrong.

Cozi and the obviously highly skilled producer Eric Berdon explore a multitude of different styles on this record. She starts with straightforward pop, with “Overruled”—one of the most melodically rewarding pop songs I’ve heard in the last 15 years (these used to be far more common). It’s so melodically satisfying that it has virtually no chance of getting radio airplay today. That’s why you need my review to learn about this record! The courtroom-based lyrical theme is a bit over the top, but give the kid a minute to grow as an artist, will you? It’s still intelligent, and musically it’s groovy, tasty, sophisticated pop.

There are more folky—possibly even with a hint of Irish folk—singer-songwritery offerings, and again the writing is strong, memorable, catchy, and sophisticated.

My personal favorite is a hypnotic dance track called “Turn the Light On.” A haunting, beautiful, and again, fully crafted and developed melody in the chorus of this song will play in your head for hours without driving you crazy. Cozi’s voice sounds ethereal, musical, and not overly processed. This kid is the real deal.

Even the swing-and-miss attempt at hip hop, “My Jam,” has grown on me. I think Cozi herself realizes it’s a bit silly for her to try to sound convincingly hip-hop, as some of the lyrics in this one are ironically self-reflective. (“As I pop and I lock in my robe and fuzzy socks…”) And again, the melody is highly singable.

If Cozi Zuehlsdorff can be taken seriously as a musician and gain some traction, I see a career shift for her. She’s a fine actress, but at her age, this is seriously impressive. Of course, my girls absolutely love this music and see Cozi as a hero and a role model. They love Katy Perry and all that other stuff too, and so it pleases me that they are falling in love with a more sophisticated brand of pop music, and from an artist who projects an ordinary-American-girl image that’s not hypersexualized.

And although the lyrical themes don’t speak directly to people my age, it’s easy to get past that. I’m happy to crank up these tunes and sing along with them when my kids are not around. (They won’t let me sing along when they’re in the car).

I really love it when this happens. Through some unimaginable series of events, I’ve come into possession of a CD I really love—a CD I did not expect to love. Cozi Zeuhlsdorff is quite obviously a cut above other young pop singers, in musical and vocal talent, in her overal depth as an artist. She’s going to do really amazing things if she keeps this up, and this is a richly enjoyable start. HIGHLY RECOMMENDED, EVEN FOR ADULTS, but GIVE IT A DAMN TRY BEFORE YOU CONCLUDE IT’S JUST KIDS’ MUSIC. THREE LISTENS.