Brief: The Koss KSC75 is a long-time bang-for-the-buck recommendation of choice on head-fi and other audio forums. I’ve owned a set for many years and they still impress me with their versatility, user-friendliness, and performance
Build Quality (6.5/10): Though they may seem fragile at first,the KSC75s can withstand a lot of abuse. The plastics of the housings aren’t particularly high-grade and the clips do come off once in a while, usually when they get snagged on something, but they are easy enough to reattach. Long-term durability is excellent and Koss’s excellent lifetime warranty deserves a nod here as well.
Comfort (8/10): Initially, they do feel a little awkward and not very well secured. The clips can be bent to fit your ears, however, and they do stay on very well. My ears can get sore from the clips after very long stretches but overall, they are very easy to wear for a long time – the clip-on design prevents headband pressure and the open, foam-padded earcups do not invoke sweat.
Isolation (2/10): The KSC75s are open headphones and will not isolate you from your surroundings or vice versa. Therefore they are less than ideal on loud busses, trains, airplanes, etc. They are perfect when you actually want to hear outside hazards though, such as while jogging, and also in reasonably quiet places (e.g. home, coffee shop, park).
Sound (6.25/10): In this motley group of test subjects, the KSC75s definitely shine in openness and fullness of sound. For the price they do almost everything right – instrument separation is surprising for a phone of this price, the midrange is full-sounding, and the highs are present in quantity and can sparkle on occasion. The bass is slightly muddy and unrefined and doesn’t extend particularly low, instead creeping up on the lower midrange. Top-end extension is similarly average, though they surpass most headphones in the price range. Soundstaging is pretty intimate for an open headphone and the overall presentation is rather forward and aggressive. The 60 Ohm impedance means that these are very forgiving and can be used straight out of virtually any source without hiss.
Value (9.5/10): The Koss KSC75s provide an unmatched combination of practicality, durability, comfort, and impressive sound characteristics at their price point. The overall sound is forward and aggressive, with plentiful bass and treble. They can also serve as a (disposable) bridge into headphone modding, backup or gym set, or decent-sounding loaner phone. Every head-fier should own a pair (or two).
Frequency Response: 15-25,000 Hz
Impedance: 60 Ω
Sensitivity: 101 dB SPL/1mW
Cord: 3.94ft (1.2m); Angled Plug
Space-Saving Mechanism: N/A