It all started with a gift to eight-year-old Felsen of a clarinet. By the age of fourteen, Felsen had his own band, and was starting to get professional party bookings. Felsen’s great musical talent and his business sense had him soon earning some bucks. “My fee was five German marks back then – a fortune in 1956,” he recalls. It became clear to Felsen that this was a viable career for him, both personally and professionally.

After finishing school in 1960, Felsen headed to Munich. “Leopoldstrasse, the Isar river, the English Garden, the Monopteros, all those bars – Munich was where life was happening,” Felsen says, his eyes shining. This sometimes came with its challenges. Felsen experienced gig's where at the venues there were fights, shootings and, “people were flying through the air.” More than once, the only way out was through the stage door. “It was really like the Wild West,” he recalls.

Felsen's time in Munich was something special. He and his bandmates were doing well, “but we hadn’t saved a penny,” he said, “that time as a musician was the foundation for my success as a music producer. I knew exactly what we had to play so that the audience would dance or clap.”

In 1970, Felsen moved to Hamburg, where his upward trajectory as a producer began with Drafi Deutscher’s “Mama Leone.” It became the number one hit in Europe. He went on to work with renowned German artists such as Torfrock, Die Rentnerband, Maik Krüger, and Klaus & Klaus. Their songs like “An der Nordseeküste” (On the North Sea Coast) all became hits and Rainer became one of the most successful German producers of the 1980s.

Despite all his success, Felsen remained down-to-earth, immensely enjoying his work and focusing on his team, the work, their quality, and the music. It was not about getting gold records; it was about the music. He helped Dieter Bohlen produce his first single even when everyone else had turned him away. "He was nice and he was talented. I just wanted to help him,” Felsen said. “The song was called ‘Komm, steig’ ein Baby blue, wenn ich dich küsse, mach die Augen zu.’ (‘Come on, get in, baby blue, close your eyes when I kiss you.’) It was a great song, but it was never released,” Felsen says with a wink.

Unlike others, Felsen didn't have the usual troubles in what can be an “industry of sharks” because he was always generous to his artists with their cut. He was all about relationships and quality. If an artist has quality, then Felsen was happy, and that’s how he came to Birkenstock.

“I’ve worn Birkenstocks since I can remember because they’re good-quality shoes,” he explains, "You just had to have Birkenstocks because they were the best – period." A more personal and practical reason for Felsen's love of Birkenstock is the temperature of his feet- they run hot, even in winter. As whimsical as that sounds, it's the truth. “That’s how I got my nickname,” he laughs, “everyone had one in the bar we’d go to: there was the Magician, the Popstar, the Drug Dealer, and the Quiet One – that guy never shut up... and they called me Sandals. Yep, I’m Birkenstock Sandals.”

“If they needed improvement, they wouldn’t be so renowned all over the world. For me, Birkenstock means quality, pure and simple.”