Mastering Engineer Holger Lagerfeldt
Online Mastering is a proprietorship run by mastering engineer Holger Lagerfeldt.
Holger has a multifaceted background, which includes being a Danish Grammy nominated producer with more than 50 IFPI-certified gold and platinum awards. In December 2004 he created Online Mastering, which is the leading facility of its kind in Denmark today.
Mastering Credits
Online Mastering delivers mastering services to Sony, BMG, EMI, and other labels. This includes platinum selling artists and projects such as Agnes, Nik & Jay, Joey Moe, Anna David, Ezi Cut, Mohamed Ali, Clemens, Niarn, Jeff, The X Factor, and many more.
You can read Holger Lagerfeldt's expanded biography and discography.
Mastering Demos
Each MP3 sound clip below changes between the mastered version and the original unmastered mix every five seconds, beginning with the mastered version.
The original unmastered mixes have been normalized to 0 dBFS for easier comparison.
- Mastering Example 1
- Mastering Example 2
- Mastering Example 3
Cutfather & Jonas Jeberg
(Producers of The Pussycat Dolls, Jordin Sparks, Kylie Minogue)
- It's important that the tracks we send to A&R's and labels sound as good as possible - and Holger at Online Mastering delivers in abundance!
Nexus Music
(Producers of J. Holiday, Nik & Jay, Joey Moe)
- Online Mastering matches the sound quality of the biggest mastering studios in New York - and offers a much more flexible service, too!
Ezi Cut
(Producer of 2Pac, Kurupt, Outlandish)
- I fully recommend Online Mastering! You get speedy delivery and absolutely first rate sound quality. I'm particularly pleased with the warm and smooth sound I get back.
Michael Guldhammer - Border Breakers
(A&R Director, Aqua, Infernal, Safri Duo)
- We definitely recommend others to use Online Mastering. Top professional service, delivery on time, and we're always pleased with the result!
Traxstarz
(Producers of Sugababes)
- With Online Mastering we get the best quality, and our sound is brought up to the highest level. Find out yourself - you'll have no regrets!
Albert Neve
(DJ, Remix of David Guetta)
- I've been looking for years, and Online Mastering.dk is without a doubt the best place you'll find. Excellent service and unbeatable sound quality!
Jesper Zar
(Producer of Daze, Das Saint, Cumfiesta)
- I use Online Mastering simply because I can't live without the quality. The bottom is super tight, the sound is clean, and the volume is crazy loud - that's how club music should sound!

(Producers of Sanne Salomonsen, Johnny Deluxe, Anna David)
- Online Mastering delivers both world-class mastering and high level customer service. We also use Holger as a sparring partner to improve our mixes before mastering.
Anna David
(Platinum selling artist, Danish Singer Of The Year)
- I'm so pleased with your mastering of my album. You came recommended to me by several producers, and I fully understand why. You've solved the problem with commitment, musicality, and a keen eye for details as well as the big picture!
Yuzo Koshiro
(Composer for Sega, Capcom, Namco, Konami)
- I use Online Mastering because I want that special dance music sound with a punchy low-end and loudness. I always love the result, it's really fantastic!
Rafael Dyll - soniQfactory
(Composer for PlayStation 3 and PC games)
- Online Mastering is a tremendous company. I was on a tight schedule, and I was impressed with the dedication and personal commitment by the engineer Mr. Lagerfeldt - and the audio quality of the result! All my future works will be mastered right here.
Sonar
(Producer and Remixer)
- I was fortunate to get a remix released on Armada, the biggest trance label in Europe. But like many other producers I am not a mastering engineer. Online Mastering provided me with great service, quick delivery, and a superb result. I'll be back!




