K340 Hybrid

About the K340 Hybrid

The AKG K340 is a discontinued hybrid headphone introduced around 1979, featuring a unique combination of an electret transducer handling frequencies above 4 kHz and a dynamic moving coil driver for frequencies below 4 kHz. This design aimed to leverage the strengths of both technologies, with the electret driver providing detailed high frequencies and the dynamic driver delivering the bass and midrange. The headphones have a closed-back design and employ passive diaphragms similar to those used in the AKG K240 Sextett. The nominal impedance is approximately 350-400 ohms, requiring powerful amplification, typically desktop headphone amplifiers or speaker amplifiers. The frequency response ranges roughly from 11.5 Hz to 23 kHz, with a sensitivity around 122 dB SPL/V. The K340 is noted for its detailed treble and midrange but has some issues with bass extension and a somewhat uneven frequency response, including a notable notch around 1300 Hz likely due to driver interaction. The sound signature varies by version, with some described as bass-light and others as more neutral or 'bass heavy.' The headphones have a cult following for their unique sound and historical significance as one of the first electrostatic-dynamic hybrids, but they are considered challenging to drive and less comfortable than some contemporaries due to weight and fit. They are no longer manufactured and are considered vintage collector's items.