In this episode, I review the Andy Audio Vault x Roseselsa CJ20, an IEM that basically shows up with a warning label attached. Andy’s own line was that if you’re not listening to rock or metal, the CJ20 might be “kind of a bit shitty,” which of course made me want to test it immediately—because my brain hears “specialist” and turns it into a deeply unnecessary quest. I go through the unboxing, accessories, build, cable, and then drag this planar through rock, metal, and everyday listening to see if it’s a beautifully unhinged genre tool or just another shiny thing pretending to be versatile. Sound-wise, the CJ20 is aggressively V-shaped: elevated sub-bass, pulled-back mids, and a pushed treble that gives it a crunchy, fast, high-contrast presentation. The planar bass is quick, clean, and disciplined—great for keeping dense rock/metal from turning into a smeary mess—but it doesn’t bring a ton of mid-bass warmth or lower-mid body. Mids trade richness for bite and clarity, and the treble is lively with good detail, though it can flirt with sharpness if you’re sensitive. Technically, it images well with respectable stage and layering, and I compare it to the 7Hz Timeless 2 as the more all-rounder option. My final take: a fun, competent specialist with a clear identity, and I rate it a strong B.