"I dislike it when I hear someone describe [my music] as weird rock, or weird techno. Surely this genre is hard to define in the music scene, because it doesn’t meet the standard of Western music charts. Hence if a rock music critic attempts to judge me [and my music], all they come up with is ambient music, or music to take drugs to. [The Japanese music scene] doesn't help with introducing terms such as New Age or transpersonality. I want to let my music reach a broader part of society, being music born from Japanese culture, and I think this is why I want to connect to the world that doesn’t exist in the music scene".
Hirasawa has an older brother, Artist Yūichi (平沢 裕一 born October 5, 1950), who goes by the moniker "YOU1". He formed a stage effects team to assist Susumu in acquiring expensive instruments during the Mandrake phase and appeared on the band's last show, running on a treadmill. Yūichi was P-Model's art Director for the band's first 9 years of existence, and has done occasional artwork for his brother from 2013 onwards. His only musical credits are for writing the lyrics of "For Kids" and "Sunshine City" (from In a Model Room), and for doing backing vocals on "Rocket" (from The Ghost in Science).
Hirasawa's music takes from such concepts as analytical psychology, advances in digital Technology, the philosophies of yin and yang, and principles of nature versus machines. As an avid fan of science fiction novels since the 1970s and an eclectic reader overall, he's been inspired by the works of Frank Herbert, Carl Jung, Hayao Kawai, Kenji Miyazawa, George Orwell, Wilhelm Reich, Antoine de Saint-Exupéry, Theodore Sturgeon, Nikola Tesla and Kurt Vonnegut.
He enrolled in the Tokyo Designer Gakuin College in 1972 and graduated cum laude in 1975 from the university's interior design course. According to the Tokyo Designers' Gakuin College '75 Design Annual, his graduation project was a dome-shaped stage set hall for Tangerine Dream shows.
In the fifth year of elementary school, Hirasawa took up the electric guitar, inspired by the surf and instrumental rock bands he heard on the radio and on TV, later joining his junior high school's band. In 1973 he formed Mandrake, a progressive rock band that incorporated elements from heavy metal and krautrock. Being one of the few Japanese progressive rock bands of its time, Mandrake achieved little success and released no albums during its lifetime.
During the early days of Mandrake, he worked as a part-time carrier on a fruits and vegetables market during the morning and at a Pepsi warehouse during the night, alongside Mandrake co-founder Fumiyasu Abe. In 1978, Hirasawa applied for a part-time lecturer position at Yamaha Music Foundation, and since he was the only person that applied for that position, he got the job. He taught courses at the Yamaha Synthesizer School until 1983, and met various Musicians that would he later collaborate with through these lectures. After leaving his position as Teacher, he took to making commercial jingle for the rest of the decade to make ends meet.
Hirasawa started smoking in 1979 and quit in 2001. He's also a teetotaler, since drinking anything larger than a fifth of a cup of beer makes him feel like his head is exploding. Regardless of that, he used to drink small amounts of wine during recording sessions to preserve his voice, which he's since replaced with throat lozenges.
Hirasawa has favored guitars designed specifically by Japanese instrument manufacturers. With a movement in the early '80s of electric guitar makers moving away from mass-producing copies of foreign designs and towards original ones, Hirasawa played many unique Models. Over a five-year period, from Mandrake's last days to the early P-Model phase, he used the H.S. Anderson Rider, Fernandes Art Wave and ESP Random Star, painting them in bright colors (burgundy, yellow, blue and white). In 1983 he settled on Tōkai Gakki's Talbo aluminum guitars as his main ones, attracted by their unique material and design. He used multiple Tōkai Talbos over an eleven-year period, with the guitar becoming an integral part of his image.
Hirasawa has used Amiga computers extensively in his work, starting out with CG production in 1987, and later on applying it on his albums and live shows, using applications such as Say, SCALA, Bars & Pipes, SuperJAM! and OctaMED. He stopped using Amigas with the LIMBO-54 shows of 2003 and the Byakkoya/Paprika albums of 2006, since "maintaining an Amiga now is, like maintaining a classic car, costly".
In 1988, Hirasawa sold a cassette book at a flea market in Yoyogi for charity, it contained 3 New Age songs made specifically for the release and came with a 36-page long booklet chronicling the self-analysis of his dreams and reality. All proceeds were donated to the Human Earth – Awakening Village (人間大地・めざめの里 Ningen Daichi Mezame no Sato) volunteering welfare facility for the mentally ill in Gunma Prefecture, which gave Hirasawa counseling during the production of the P-Model album Karkador.
In 1989, Hirasawa launched his solo career. Unbound by the restraints of a band, his albums were marked by a refusal to stick to any particular genre. He continued to evolve his sound while concurrently working with two different iterations of P-Model until the group was disbanded in 2000. He has actively been releasing new music since.
Hirasawa has worked since the start of his solo career to decrease the amount of performers around himself. Most of his solo albums from 1992 onwards feature no guest Musicians, and live backing bands were relinquished in 1994. Since then, only a few select shows have had guest Singers or backing instrumentalists.
As Hirasawa objected to the American response after the September 11 attacks, which he believes involved excessive Carnage, and the Japanese government's aiding of such actions, he offered downloads of online banners and two of his songs for free, which he hoped would be used as tools of objection. One of them is a rerecording of 1994's "Love Song", which is about children in the battlefield; the other is "High-Minded Castle", about a man who "can not know the truth and true background through media, he tries to face the real tragedy on the other side of the world". The latter was taken from the Blue Limbo album, which displays a dystopian theme partly influenced by the American government's retaliation.
In the '90s, Hirasawa gradually moved his work from professional facilities to home, dubbing his workspace on various residences "Studio WIRESELF". He finally moved completely to it by the recording of 2000's Philosopher's Propeller. The following year he undertook the sustainable Energy project "Hirasawa Energy Works" and changed his lifestyle so that all his music would be recorded with solar Energy. To reduce carbon emission, Studio WIRESELF was outfitted to be powered completely by a photovoltaic system of 2 solar panels, with 2 car batteries to store extra Energy. Years later, Hirasawa added 2 more panels to the studio and retired the batteries.
In 2001, a pregnant stray cat appeared in Hirasawa's studio. He took care of her and helped carry out four of her pregnancies from 2001 to 2002. Since he could not take care of all the kittens, Hirasawa created a temporary site to recruit possible adopters and keep up with the welfare of the various cats.
In the aftermath of the 2011 Tōhoku earthquake and tsunami and the Fukushima Daiichi nuclear disaster, Hirasawa started traveling around the country with a Geiger counter, measuring the radiation levels and reporting them in his Twitter account. In June 2011, a song was posted on his site, titled "Nuclear Power" (原子力 Genshiryoku): A rerecording of the P-Model song "Boat" (from 1984's Scuba) in the style of "The Aggregated Past – Kangen Shugi 8760 Hours" project, with the lyrics changed to protest against Japan's use of nuclear power and to criticize the government and the media. The song, credited to "Stealthman", was only available on the site for six days, but could be redistributed if unaltered and not for profit. An instrumental mix was posted on the site by Hirasawa after the original was taken down, following the same distribution guidelines. As these events occurred, Hirasawa told a story on Twitter of being assaulted and having his computer and website hacked by "Stealthman". Through his tweets and the way the posts were worded on his website, Hirasawa effectively distanced himself from the track and disowned it. The song is available on the karaoke Service provider Xing's Joysound online song library, credited to "Stealthman".
In 2013, Yūichi opened the café bar Gazio in Tsukuba. Although branded as a "new wave" café, the establishment was heavily themed around P-Model and Susumu: it was adorned with various band related memorabilia, served original cocktails titled after his songs and often held special events and shows by members and associates of the band; Susumu made exclusive content for it and, as he gives his brother most things he has no need for at a given moment, many studio and stage objects were displayed in the café. Gazio ceased operations as an active restaurant in 2015 and rebranded as an art studio; Yūichi now holds twice monthly "Café Gazio" events in Kichijōji.
While repeatedly incorporating various concepts from Shintoism and Buddhism in his themes, as well as ones from other Asian religions, Hirasawa has never specified what his beliefs are. However, at one point in time, he supported the return of the imperial cult of the Emperor of Japan as a psychological measure: "I think His Majesty needs to recover his glorification. In this matter, I’m sort of right wing; the Emperor of Japan needs to regain his symbolic position as a God. But this is for the sake of a healthy process of collective consciousness, so please don't lump my position in with all the militaristic talk".