Наушники — Koss KSC21

The KSC21 is the entry model of the Koss ear clip family, a wired headphone that hooks over the ear rather than sitting on a headband. Koss lists it at USD 9.99, which places it below the KSC22i at USD 19.99, the KSC75 at USD 24.99 and the KSC35 at USD 44.99 in the same range of clip-on designs. Two finishes, black and white, are listed, and the model carries the Limited Lifetime Warranty that Koss applies to its wired ear clip headphones.

Key specs that matter

Koss quotes 50 Hz to 18,000 Hz as the response range, and the nominal impedance is 36 ohms. No sensitivity or distortion figure is given in its KSC21 listing. The cable is straight and enters both earpieces, a dual entry layout, and runs 1.2 m to a standard 3.5 mm plug. The 36 ohm load sits between the 16 ohm KSC22i and the 60 ohm KSC35 and KSC75 within the same family.

Engineering and use context

Each earpiece carries a pivoting ear plate, so the clip and the driver housing can move relative to each other as the wearer positions them over the ear. Soft foam cushions cover the front of the plates. Koss describes the construction as open with a hear-through character, intended to keep the wearer connected to the outside world while listening. The maker also calls the design lightweight and over the ear, with wide range, extended frequency response as its stated goal. This version omits a microphone and remote, unlike the KSC22i, which brings an in-line mic plus a TRRS plug for use with phones. The KSC21 therefore works purely as a listening headphone, with the cable carrying audio to the two earpieces and nothing else.

Pairing

The plug fits phones, tablets, laptops, portable players and other sources that carry a standard headphone socket. Koss positions the ear clip range for use both at home and while travelling, and its impedance rating is the kind of load such portable sources are built to drive. The cord length matches the other wired ear clip models, including the KSC35 and KSC75, so switching between them does not change how far the source can sit from the listener. For listeners who want wireless operation in the same clip-on form, Koss offers the KSC35 Wireless with Bluetooth 5.2 and a rated 18 hours or more of battery life, while the KSC21 stays with a fixed cable and no battery to charge.

Alternatives

Within the same ear clip range Koss also sells the KSC75, which adds titanium coated diaphragms and a published 101 dB sensitivity at a higher impedance.