Koss KSC75: Softness And Nuance

The Koss KSC75 is an ear-clip model that uses the same basic approach (open supra-aural) as the famous PortaPro, which made Koss more or less a standard for quality mobile earphones. Here the headband has been done away with in favor of a simple ear-clip, and the result is a set of earphones that's non-bulky, very light, and very comfortable. In practice, the KSC75s can be put on in a flash and with no danger of putting them on the wrong ear. The pressure on the ear is practically nil, but so is the sonic isolation. Don't expect them to attenuate ambient noise so you can get lost in your music! The other side of the coin is that it's easy to forget you're wearing them, since the acoustical environment seems undisturbed. The absence of isolation is very pleasant provided you aren't in noisy surroundings. If that's not the case, this set will not suit your needs very well. The cable is of medium length, well suited to use with a portable player, and ends in a gold-plated 3.5 mm angled mini-plug.

Technical Characteristics

  • Type: open supra-aural ear-clip
  • Frequency response: 15 Hz - 25 kHz
  • Nominal impedance: 60 ohms
  • Sensitivity: 101 dB/mW
  • Cable length: 4 ft. (1.2 m)
  • Plug type: 3.5 mm angled mini-plug
  • Weight: 29 g (1.02 oz)

Natural And Balanced

This model logged response figures that were nearly identical to those of the PortaPro, which confirm the family resemblance. That's fine with us, because response was extended and regular, with almost perfect balance. The only criticism I have is about the gradual attenuation of the low bass - a characteristics that's hard to avoid with this type of earphone.

Measured on the artificial ear, the KSC75 showed remarkably regular response with good extension.

The efficiency is high and will produce a sufficient sound level with any player, though it won't attain the high levels other models can. You'll be less tempted to ruin your hearing...

Efficiency: approximately 101 dB/V

Listening Test

With this earclip model, Koss has succeeded perfectly in carrying over its success with the PortaPro to a very practical and pleasant model for portable use. As the tech tests led us to hope, the KSC75 delivered excellent overall listening quality with very pleasant balance and fullness. The midrange was responsive and precise, but without aggressiveness, and that set of qualities is not easy to bring together in one place.

Selections known to easily bring out any aggressiveness in a reproduction system were no problem. Yet the highs didn't appear truncated. The bass was well in evidence and had very nice presence, ampleness, and detail. On the other hand, the low bass was perceptibly less evident - which is not a big surprise. But that wasn't really obvious except with selections containing very low frequencies, which isn't often the case, and it's acceptable. It's a fairly common trait of this type of earphone, where reproduction of the very low bass is rarely as good as on a larger model or with certain intra-aural sets. Unless you're looking for acoustic isolation, the KSC75 is an excellent choice.


The Good

  • preciseness and balance
  • detailed but gentle midrange
  • practical and pleasant to wear

The Not So Good

  • low bass lacks ampleness
  • no acoustic isolation
  • Uncomfortable? These are the most comfortable headphones I ever used (among Koss, AKG, Beyer and other Senn models).
  • JT Kahle
    ive had a pair last 6 years, falling asleep with them on almost every night.