7Hz Headphones

The Zero:2 is what happens when the internet's most influential IEM reviewer retunes an already-famous $20 earphone: it takes the original Salnotes Zero's near-neutral signature and adds a tasteful bass shelf, and the result is widely treated as the default answer to 'best IEM under $50.' Owners who own both this and the Moondrop Chu II consistently call the Zero:2 the cleaner, better-balanced listen — energetic low end, natural mids, and a treble that stays smooth without sounding dull. The 10mm dynamic driver with its PU-and-metal composite diaphragm keeps distortion impressively low, and the detachable 0.78mm 2-pin cable means the usual budget failure point is replaceable. At 32 ohms it's slightly less sensitive than some rivals but still runs fine from a phone or laptop. The honest caveats: the shells are lightweight colored plastic that looks toy-like next to metal rivals, the stock silver-plated cable is serviceable rather than nice, no case or extras beyond tips are included, and the short nozzles give some owners real trouble getting a seal — plan on tip-rolling if your canals are deep. Colorways are loud (the classic is a blue-and-white combo; this listing is orange). As a first IEM, a beater pair, or a reality check on how good $25 can sound, it has no serious weaknesses.

Best for The best-tuned $25 in-ear, full stop