hrtz.wav Drop Second Album in 5 Months and Already Have Lollapalooza in Their Sights

Five months after their April debut, hrtz.wav walked into a showcase at S-Factory in Seoul's Seongsu-dong on the 9th and made one thing clear: Kakao Entertainment is not letting this band idle. The second mini-album, The Second Wave: MOMENTUM, arrived the same day, and the group brought a RIIZE feature, a full genre pivot to synth-pop, and Lollapalooza headliner ambitions along with it.

hrtz.wav formed through Steel Heart Club, Mnet's band-making survival show, with each member having ranked first at their respective position. The lineup is Yoon Youngjun on keyboards, Rian on vocals, Dane on bass, Kaiten on guitar, and Hagiwara on drums. The name fuses "hrtz" (hertz, representing the frequency of the heart and sound) with "wav" (the audio file format, evoking high-fidelity waves), which, as origin stories go, is more apt than most.

A deliberate turn toward synth-pop

Their debut record leaned into breezy pop-rock. For the follow-up, the group made a conscious decision to shift toward synth-pop, and every member contributed to the writing and composition of all six tracks. Dane even bought a synthesizer specifically for this project.

"The genre of the second album was something we debated a lot," the members said at the showcase. "Synth-pop was the sound that felt most natural to each of us, and we stayed up all night working to make sure everyone's strengths came through."

Rian elaborated on the reasoning: synth-pop gave Youngjun room to showcase his keyboard work, matched the high-energy output of Kaiten and Hagiwara, and opened up new sonic territory for Dane's bass. The five members span different musical backgrounds and nationalities (Korean and Japanese), and Youngjun noted that the variety in their individual tastes is part of what keeps the creative process from going stale. "The process of weaving those different ideas together is how we find the sound that's specifically ours," he said.

What's on the record

The title track ALIVE is a mid-tempo electronic synth-pop number built on a groovy, retro-tinged synthesizer bed. RIIZE's Sungchan features on the track, adding another layer of textural contrast to hrtz.wav's live-instrument core. The band described the song as capturing the feeling of emotions growing sharper and more vivid as two people draw toward each other.

The remaining five tracks cover a range of moods. Mind, led by Rian and Dane, lays honest longing over a lyrical synth-pop arrangement. Sunday Morning goes lighter, carrying early-crush energy with an upbeat feel. Play My Guitar, which draws from Kaiten's personal story, is an uptempo pop-rock track about growing up dreaming of becoming a rock star. Thinkin' Bout You, built collaboratively through a songwriting camp, has a retro synth-pop character. First Daylight is a modern rock track built around the band's instrumental firepower.

Kaiten is a Berklee College of Music graduate, and that technical foundation shows in how the group handles the wider sonic range across the tracklist without it feeling scattered.

Five months of stage time, already

Since their April debut, hrtz.wav has performed at more than ten major domestic and international festivals. In May, Kaiten and Hagiwara's home country of Japan hosted KCON JAPAN 2026, where the group performed and drew a strong response from local fans. The members say they review every performance closely afterward, looking for weak points to correct.

That live accumulation is the early indicator worth watching here. A rookie band that plays ten-plus festival stages in its first five months is developing real-world performance instincts at a pace that studio-only acts cannot replicate. The ceiling for a band with that kind of road work behind them tends to be higher than their chart position at this stage would suggest.

As for dream stages: Youngjun named Madison Square Garden. Hagiwara, performing in character as always (he appears masked in a white disguise with a voice modulator, playing a persona officially described as a 3-year-old born in 2022), cited Summer Sonic in Japan, the festival closest to his roots. Dane went biggest: "Someday, I'd love to headline Lollapalooza."

With two mini-albums in five months and a growing festival résumé, hrtz.wav's momentum is more than just the album title. Circle September 9 as the date the synth-pop pivot started.