STEREO: Inside the Electronic Side-Project of Haloo Helsinki! Masterminds

When one of Finland’s biggest pop-rock bands takes a break, what do its creative forces do? For Leo Hakanen and Jere Marttila—the renowned guitarists and primary songwriters behind Haloo Helsinki!—the answer was a bold, creative leap into electronic dance music (EDM) under the moniker STEREO.

Active primarily during Haloo Helsinki!’s well-publicized hiatus in 2018–2019, STEREO allowed Hakanen and Marttila to step out from behind their rock guitars and into the roles of DJ-producers and vocalists.

The Birth of the Duo

STEREO burst onto the Finnish music scene in February 2019 with the simultaneous release of their debut singles, “Vuosien päästä” (featuring rapper Etta) and “74”. Born out of a shared desire to explore fresh sonic landscapes, the project served as an energetic playground where the duo could experiment with modern electronic production, heavy synthesizers, and club beats while maintaining the sharp, catchy songwriting sensibilities that made Haloo Helsinki! a household name.

The production value of the project was high-profile from the start. Notably, their breakout single “Vuosien päästä” was mixed by Miles Walker, an internationally acclaimed mixer renowned for his work with global superstars like Beyoncé, Bruno Mars, Coldplay, and Rihanna.

The Debut Album: 00740

In November 2019, STEREO cemented their project with the release of their full-length debut album titled 00740. The record showcased a diverse array of electronic styles, ranging from atmospheric synth-pop to high-energy EDM designed for festival main stages and club floors.

Rather than working in isolation, Hakanen and Marttila opened the studio doors to a wide cast of prominent Finnish vocalists and artists, transforming the album into a collaborative celebration of contemporary Finnish music.

A Star-Studded Cast of Collaborations

One of the defining features of STEREO’s tracklist was its heavy reliance on cross-genre guest features. The album and its accompanying single releases featured an impressive roster of talent, including:

• Samu Haber on “Sä saat mut palasiksi”
• Michael Monroe (of Hanoi Rocks fame) on “Woo Woo”
• Etta on “Vuosien päästä”
• Ida Paul & Kalle Lindroth on “Bonnie & Clyde”
• Sini Yasemin on “Katon peiliin”
• Aste on “Rauhaa ja rakkautta”
• Markus Salo on “Joo mä elän”
• Teflon Brothers on “Marijuana”

This collaborative spirit allowed STEREO to bridge disparate musical worlds—blending pop hooks, hip-hop verses, rock attitude, and electronic dance music into a seamless, high-energy package.

Legacy and Impact

Though STEREO was conceptualized as a focused side-project tailored for the duration of Haloo Helsinki!’s hiatus, it proved the dynamic versatility of Hakanen and Marttila as modern music producers. By delivering sharp electronic production and unforgettable collaborations, STEREO carved out a unique, vibrant chapter in modern Finnish pop culture history.