Beyond the Arena: The Story of Stereo, the Electronic Side-Project That Redefined Finnish Pop Icons

When one of Finland’s biggest stadium rock bands enters a hiatus, what do its principal architects do? For Jere Marttila and Leo Hakanen—the guitarist and primary songwriter/guitarist, respectively, of the multi-platinum-selling behemoth Haloo Helsinki!—sitting still was never an option.

In 2018, as Haloo Helsinki! stepped off the touring grid for a much-deserved break, Marttila and Hakanen pivoted hard away from massive guitar riffs and arena-rock anthems. Instead, they dove headfirst into the neon-drenched, nocturnal world of electronic dance music, giving birth to Stereo (stylized as STEREO).

From Stadium Rockers to Electronic Architects

For over a decade, Marttila and Hakanen had helped shape the soundscape of modern Finnish rock through Haloo Helsinki!, known for chart-topping hooks, poetic lyricism, and high-energy live spectacles. However, Stereo offered a blank canvas—an opportunity to experiment without the stylistic boundaries of a traditional band setup.

Stepping behind the synthesizers and drum machines, the duo leaned heavily into contemporary electronic production, urban club rhythms, and atmospheric pop textures. While they retained their innate gift for crafting colossal, radio-friendly hooks, Stereo felt darker, sleeker, and entirely untethered from their primary musical home.

The 2019 Breakthrough and the 00740 Era

Stereo made their official arrival felt swiftly and comprehensively in 2019, rolling out a string of high-profile collaborative singles before releasing their debut full-length album, 00740, later that year.

Rather than working in a vacuum, the duo transformed Stereo into a collaborative collective, inviting an elite cross-section of the Finnish music industry into their sonic universe. The tracklist read like a who’s who of Finnish pop and hip-hop, resulting in an eclectic, dynamic album experience:

• “Vuosien päästä” (featuring Etta): A massive streaming success that showcased how seamlessly Stereo’s melancholic electronic production blended with modern urban rap flows.
• “Sä saat mut palasiksi” (featuring Samu Haber): A soaring, emotionally charged track combining Haber’s distinct, gravelly vocals with pulsing synth-pop beats.
• “Woo Woo” (featuring Michael Monroe): A brilliant collision of punk royalty and electronic groove, featuring the legendary Hanoi Rocks frontman.
• Additional Collaborations: The duo teamed up with artists like Sini Yasemin, Ida Paul & Kalle Lindroth, Aste, and Teflon Brothers, proving that Stereo was as much a social experiment in genre-crossing as it was a production project.

A Temporary Flash or a Lasting Legacy?

Stereo was conceived explicitly as a creative outlet for the duration of the Haloo Helsinki! hiatus. Yet, the project left an indelible mark on the Finnish music scene. It demonstrated that mainstream pop-rock songwriters could deconstruct their abilities and rebuild them within the framework of electronic dance music without losing their core identity.

Though Marttila and Hakanen eventually returned to their primary duties with Haloo Helsinki!, 00740 and its surrounding singles remain a fascinating chapter in modern Finnish pop history. Stereo proved that true musicianship isn’t bound by genre—whether they are wielding stadium guitars or programming late-night club beats, Marttila and Hakanen know how to make Finland move.

Did You Know? The album title 00740 is a playful nod to postal and regional numerical identities, encapsulating the project’s urban, late-night aesthetic right down to its cataloging.