AKG K240 MKII Semi-Open Over-Ear Studio Headphones with Two Cables

AKG K240 MKII: The Semi-Open Studio Classic

The AKG K240 MKII is a semi-open over-ear studio headphone built around patented Varimotion XXL 1.2 in. (30 mm) transducers, with a 55 ohm impedance and a rated response of 15 Hz to 25 kHz. Its long tenure in studios, schools and broadcast facilities comes from a specific combination: a spacious presentation that is easy to wear for hours, and a fully serviceable design whose two highest-wear parts are both supplied in duplicate. In the box are two detachable cables, two complete earpad sets in different materials and a locking screw-on 1/4 in. adapter. It is a headphone bought to stay in service, not to be replaced.

What Semi-Open Actually Means for Your Session

Acoustically this is a semi-open design, meaning the rear of each earcup is partially vented to the room rather than fully sealed or fully open. Venting relieves the pressure that builds behind a sealed diaphragm, which is what removes the boxy, in-your-head quality of closed monitoring and lets the top end breathe, but it also lets sound out and room noise in. That trade decides where these belong: excellent for mixing, editing, keyboard practice and cue listening for a bass player or keyboardist, and a poor choice for a vocalist standing in front of a sensitive condenser, because at realistic cue levels the click and backing mix will leak into the take. Understanding that boundary is the single most useful thing to know before choosing them, because the semi-open presentation is genuinely more comfortable to listen to for a long editing pass than a sealed cup.

Varimotion XXL Transducers and Diaphragm Damping

Each earcup carries a patented Varimotion XXL dynamic transducer measuring 1.2 in. (30 mm), whose diaphragm thickness deliberately varies across its surface instead of staying uniform. Uniform diaphragms ring at their own resonant frequencies, adding coloration and harshness at those points; varying the thickness spreads and damps those modes mechanically, which widens usable dynamic range and smooths the response before any EQ is involved. The stated bandwidth runs from 15 Hz at the bottom to 25 kHz at the top, wide enough to hear low-frequency rumble in a location recording and the cymbal detail in a drum overhead. Podcast editors chasing an air-conditioning hum and project-studio mixers judging a bass balance both rely on that honest, unhyped presentation.

55 Ohm Load, 104 dB Sensitivity and 200 mW of Headroom

Electrically these present 55 ohms with a sensitivity of 104 dB SPL/V at 1 kHz and accept up to 200 mW of input power. A 55 ohm load sits in the range designed for professional console and interface headphone outputs rather than for a phone, so a proper cue send or headphone amplifier will produce noticeably more level and authority than a laptop jack will. Power handling of 200 mW is the specification that matters when a drummer asks for a loud click over a live kit, because it means the drivers accept that energy without distress. Institutional studios wiring a dozen positions off a headphone distribution amplifier get consistent, predictable level across every seat as a result.

Single-Sided Detachable Cabling and Long Service Life

Cable entry is single-sided, so only one earcup carries a lead, and it detaches at a professional 3-pin locking mini connector. Single-sided cabling is a practical detail rather than a cosmetic one: there is no cable looping across the chest to snag on a keyboard stand or a mixing desk, and there is only one connector to fail. Two leads are supplied, the EK300 straight cable at 9.8 ft (3 m) for desk work and the EK500S coiled cable at 16 ft (5 m) for a tracking room where the player moves around, both terminating in a gold-plated 3.5 mm stereo plug with a screw-on 1/4 in. adapter that locks rather than dropping into the back of a rack. Because cables detach and earpads are replaceable, a rental house or a university lab can keep the same units running for years by swapping the two parts that actually wear.

Two Earpad Materials, Self-Adjusting Fit and Who These Suit

Both a velvet pair and a leatherette pair of earpads are included, and switching between them is a genuine tonal and comfort decision rather than a cosmetic one. Velvet breathes, so it runs cooler through a long editing session, while leatherette seals more tightly against the head and therefore delivers more perceived low-frequency weight; having both means one headphone covers both preferences. Suspension is a self-adjusting headband that finds its own position with no sizing sliders to set, and the circumaural earcups sit around the ear rather than pressing on it, which spreads clamping force over a wider area. Project studios, school and university labs, broadcast edit suites and musicians who dislike the pressure of a sealed cup are the natural buyers, with the one caveat that these do not fold for transport.