An open-back 85 mm planar (25 Ω, 92 dB/mW) that wants a little more power than average, and at 471 g on Headfonics' scale it is heavy. Sources agree on three things. The bass is punchy, tight and extends deep. The all-metal build and soft leather pads look and feel more expensive than the price. The soundstage is wider than average and a little shallow. Dynamics are described as lively, even exaggerated. Opinion splits on the upper half of the range. Most reviewers hear an elevated, sometimes grainy or peaky treble, while a smaller group hears clean, well-behaved sparkle. The midrange is natural to most, but hollow or distant to two listeners. The overall voicing gets described as warm, V-shaped or balanced. On value, the reviews divide almost evenly. Four independent measurement rigs agree on a mild low-end lift, a normal-height ear-gain peak at about 3 kHz, and a notch right after it at 4 kHz that the HiFiMan and FiiO planars on the same rigs don't show. Above 6 kHz the rigs and seatings disagree, which lines up with the treble split. Separately, one reviewer was told by TANGZU and two retailers that replacement pads aren't sold.
About this product
TANGZU's first full-size headphone (牛魔王, "Bull Demon King"), an open-back 85 mm planar released in December 2025. It ships with a single-ended 3.5 mm cable; the silver 4.4 mm "Iron Cudgel" cable is a separate upgrade (and was bundled with the first 150 units sold direct). Not TANGZU's later Li Jing headphone.
TANGZU made its name with Tang-dynasty-themed in-ear monitors like the budget Wan'er. The OX Demon King, named for the bull-demon of Journey to the West, is its first over-ear headphone: an open-back planar with an 85 mm driver in machined aluminium cups behind a lattice grille, with leather pads that twist-lock onto the cup. It launched at $349, directly against HiFiMan's Edition XV and Sundara, Meze's 105 AER and Audio-Technica's R70x.
Nine months on, reviewers broadly like how it is built and how its bass hits. They disagree on what it sounds like overall: one camp hears a warm, bass-led planar, another a lively V-shape with a bright, peaky top end. A few call it balanced. Four measurement rigs help explain why.
