Killian “Don Grizz” Radtke is a London‑based DJ, record collector and hi‑fi culture curator whose 25‑year career began after relocating from his native Germany in the early 2000s. A founding member of the improv night Open Sauce—which hosted artists from Ninja Tune, Big Dada and Wichita Recordings—he became a resident at pioneering listening venue Spiritland King’s Cross in 2019 and has since graced sister rooms at Spiritland Royal Festival Hall, Brilliant Corners and Behind This Wall, as well as Curtis (Barcelona), RIAA (Hamburg) and H/earth (Amsterdam). His eclectic, vinyl‑only sets span jazz, funk, dub and global grooves and can be heard on Run Dem Radio, Islington Radio, Music Box Radio, Voices Radio and Amsterdam’s Radio Salto. Now, with Hi-Fi Horizons, Radtke channels decades of crate‑digging and event‑building into a definitive visual chronicle of the worldwide Hi‑Fi listening‑bar explosion.