Exclusive Interview
Oct 21, 2024
Produced by: Andrej Aroch
Edited by: Rudy Manager & Andrej Aroch
Koen Heldens – "Technical precision isn’t always the answer; music is about emotion and feel"
Cover Photo Shot by @vombagram
Studio Talks had the privilege of interviewing Koen Heldens, a renowned mixing engineer who has collaborated with some of the biggest names in music. From his early days as a young music enthusiast in Holland to becoming a pivotal figure in today’s industry in Los Angeles, Koen’s journey is one of passion and perseverance. Known for his innovative work with artists like Trippie Redd, Ski Mask The Slump God, and Lil Yachty, his most notable achievement is his collaboration with XXXTentacion, including the Diamond-certified, No. 1 single "SAD!"
In the interview, Koen delves into his creative process, the obstacles he overcame to break into the industry, and his experience working with XXXTentacion—from the artist’s early success to posthumous releases. He also shares valuable insights on modern mixing techniques and offers advice for aspiring engineers.
What sparked your initial interest in music, and how did that passion lead you to pursue a career as a mixing engineer?
I was first introduced to music as a kid when my parents enrolled me and my siblings in music school. We learned to play the recorder and how to read and write music. Later, I tried guitar, but being left-handed with a right-handed teacher made it a challenge. That was the beginning of my musical journey.
Fast forward to high school, when I was around 12. My older brother brought home some music composition software and installed it on our family computer, but gave me the typical warning: “Don’t touch the software.” Naturally, when he wasn’t home, I started exploring it and gradually began building my own compositions. Eventually, I got my hands on some hardware—synths and drum machines—and started making full tracks. By the age of 14, I was burning CDs and sending them to record labels, which led to my first publishing deal.
At 16, my music publisher told me, "You’ve got talent, but your mixes need to improve—significantly." That’s when my obsession with mixing began. I wanted to master the craft, but at the time, there wasn’t the convenience of online tutorials or YouTube. I had to learn by observing others and being in rooms where the magic happened.
I started working weekends at a live sound company in Rotterdam. A mutual friend connected me with the owner, who was building a recording studio and invited me to help out. While the studio was under construction, I assisted with PA events, which eventually led to me becoming an assistant engineer. His mentorship was critical in shaping my early knowledge.
Later, I worked at another studio in Rotterdam called Liquid Spillers, which was the first in Holland to have a Neve 88R console. It was a huge, ambitious project in the old Heineken brewery cellar, but sadly, the studio went under after six months. During that time, I learned a lot by working with U.S. clients and engineers, giving me my first taste of the American music industry.
When Liquid Spillers closed, former international Dutch soccer player Winston Bogarde opened a studio in Amsterdam, where I became chief engineer. But I soon realized that Holland’s music scene was limited in terms of artist quality and record production. That’s when I started reaching out to people through MySpace and began traveling to the U.S. for 90-day visits. After a year or two, I applied for an O-1 artist visa, which was approved, allowing me to stay in the U.S. full-time.
That was my journey from composer to engineer to mixer, and mixing is what really stuck with me. It’s where I found my true talent and passion.
Shot by @vombagram
You’ve worked on some of X’s posthumous albums. What’s your take on posthumous releases, and did you approach the mixing process differently for those projects?
When X passed, Skins was technically a posthumous release, but we had already made significant progress while he was still alive. I started mixing some of the tracks in March, and most of the work happened in May. Sadly, he passed away in June, but I’d say about 90%—if not more—of the album was already completed by that point. So, I don’t really view Skins as a full posthumous album. Bad Vibes Forever, however, was different; it was fully posthumous since X was no longer with us.
Personally, I’m not a huge fan of posthumous releases. It’s difficult to truly capture the artist's vision when they’re no longer here, especially with someone like X, who constantly pushed boundaries and reinvented himself. The challenge often lies in the business side—there are contracts and deals with record labels that have to be fulfilled, regardless of the artist’s passing, which adds complexity. From a business standpoint, I get why these albums happen.
It’s a delicate subject, and I’m often torn. On one hand, keeping the artist's legacy alive is important. But on the other hand, it feels strange because the artist can’t be present to execute their true vision, if that makes sense.
Have you noticed any new mixing techniques trending now compared to when you first started?
One technique that’s become very trendy lately is clipping. When you first learn engineering, you’re taught that gain structure and signal flow are essential, and the rule is always: “Don’t clip the signal.” I remember back in my early production days, when I wasn’t paying attention and the mix bus was clipping, it often sounded better than when I meticulously gain-staged everything to avoid it. I didn’t fully understand why until I got deeper into engineering.
You don’t quite grasp it until you’re in the studio with an experienced mixer and see the whole board lighting up red. When everything is hitting the red, nonlinearities start to appear, and that’s when you begin to listen and feel the music more deeply. You realize clipping can help achieve louder levels, which is still crucial in today’s loudness wars. Clipping can actually be beneficial, especially for transient-heavy sounds like drums.
Personally, I only clip my drums and bass. I send all the drums and bass to a single subgroup, add a bit of compression, and then boost the high end slightly to counteract any loss from the compression. After that, I hard clip the signal. The amount of clipping I apply varies depending on the record—sometimes 2 dB is enough, while other times I push it to 5 or 6 dB. At that point, the interaction between the kick and bass creates a groove that can really elevate the track.
Shot by @vombagram
What’s one record you worked on that stands out as your favorite, and what made it so special?
My favorite record has to be “SAD!” That session was incredible. I vividly remember getting a FaceTime call from X right after he finished recording it. He told me, "Hey, I have this record—it's going to be a number-one hit." I loved challenging him, but he consistently proved me wrong, which was amazing. It was one of those moments where what initially seemed like an illusion of grandeur actually became a reality.
He sent me the track and said, "I need the mix back in an hour." Naturally, I thought, “An hour? That’s impossible.” However, after listening to it, I immediately felt compelled to push the snare way out front—making it loud and prominent. There was no second verse, despite some discussions about adding one, but it didn’t need it since the song didn’t follow a typical structure.
Something else happened by accident: I had a delay line on the lead vocal, and for some reason, the feedback was almost infinite, which I would never normally do. I usually keep the delay feedback around 10%, so it only delays once, but this time it just kept going. So, after the hook ended, you could hear the vocal echoing throughout the open verse part. It was a happy accident.
Two key elements made the track stand out: the loud snare and the almost infinite delay. For the kick drum, which sounded a bit thin—almost like a barrel-type kick—I re-amped it through an Ampeg 8x10 bass amp with the SVT bass head. I flipped the phase on its return channel and high-passed it at 150 Hz. When I blended that back in with the original kick, it became massive.
Although the record is simple, it's the little details that made it unique. When it was released, it charted, and after X passed away, it hit number one, streaming over 10.4 million times in a single day. At that point, it even held a Guinness World Record. We no longer hold that title—Mariah Carey’s “All I Want For Christmas Is You” reclaimed it—but “SAD!” remains a special track. By traditional sonic standards, one might think, “The snare is too loud, the delay is excessive,” but it all worked perfectly for that record.
What advice would you give to someone looking to start a career as a mixer?
If you're just starting out and aspiring to become a mix engineer, my main piece of advice is to begin as a recording engineer. Get a solid understanding of the recording process, the equipment, and the software you’ll be using.
It’s also essential to learn how to navigate interpersonal dynamics—it’s part psychology and involves reading and managing the room's energy. This will help you build connections with artists. Once you establish a genuine rapport with an artist, you’ll likely become their primary recording engineer, paving the way to transition into their go-to mixer.
Start locally, work the rooms, and focus on building those relationships. As you begin doing rough mixes for the artists you record, you could eventually become their mixer. As you improve, start pitching for final mixes. Once you land a few of those, you’ll begin to build a portfolio of work that can lead to more mixing opportunities.
What are your plans for the rest of this year? Are there any projects you’re currently working on that you can share?
I have a few exciting projects in the works. One of them is a Christmas single for an artist at Capital Records.
Additionally, I’m working on a remix featuring two prominent artists, both of whom have sadly passed away. The original track was released while both artists were still alive, and the remix was completed after one of them passed. I remember seeing the artist post about the video on his Instagram multiple times before his passing. This project resurfaced a month or two ago, and we finally wrapped it up just a week or two ago.
Overall, there are several cool records set to be released before the year ends.
Follow Koen Heldens on Instagram: @mixedbykoenheldens
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