Second, the KDE250’s midrange is also quite smooth, but is pushed just slight forward relative to higher and lower frequencies. , giving these headphones a somewhat midrange-centric character overall. To hear this quality in action, put on “Seven Wonders” from Nickelcreek’s This Side [Sugar Hill, SACD], and pay close attention to the way the Koss 'phones handle the Sara Watkins’ violin, Chris Thile’s mandolin, and the upper register of Ms. Watkins’ voice. What I observed was that violin, mandolin, and voice sounded open and exhibited pristine clarity, but that they were also more penetrating and prominent than they would normally be with a more neutrally-voiced transducer in play. Still, I think most listeners would be so enthralled by the Koss’ terrific openness and transparency that they consider the KDE250’s midrange forwardness more a blessing than a drawback.
Third, upper-bass is well balanced, while mid-bass is somewhat more lightly balanced, and low bass is recessed further still. In truth, very low bass is not deeply extended—at least not down in the bottom octave where the deepest pipe organ notes live. In practice, this means the KDE250 can sound quite pleasing on records with solid upper and mid-bass content, but it is perhaps not the best choice for listening to music that requires a strong bass foundation down below about 40Hz. In fairness, however, let me point out that the KDE250’s bass has beautiful definition, detail and clarity, so that bass quality is consistently high—even if some might want for a bit more bass quantity.
The bass characteristics of the KDE250’s can easily be observed if you put on a track such as “Bass ‘N’ Drums” from John Paul Jones’ Zooma [Discipline US]. This track features the legendary Led Zeppelin bassist performing a syncopated, jazzy electric bass solo accompanied only by a drum kit. The Koss 'phones do a fine job with the upper register of the bass, capturing the “snap” and “bounce” of Jones’ inventive licks, while also making (most of) the drum kit sound very realistic, too. But, the lower Jones goes on his bass the more lightly balanced the instrument sounds and the drum kit’s kick drum seems lack both in appropriate punch and weight—almost as if it has gone AWOL in the mix, which is really not how this recording can or should sound.
Top-to-bottom clarity and definition are both very good—better, in my estimation, than is the norm for this price class. Part of this, I think, has to do with the KDE250 unique design, which consistently lets you enjoy qualities of openness or transparency, but without feeling like you are being “force fed” sonic minutia that doesn’t really contribute to the musical whole.
• Consider this product if: you want a headphone that offers excellent openness and transparency, that is very light and comfortable, that can be dialed in for a precision fit, and that gets around the tight-fitting, “my-ears-feel-plugged-up” sensations that traditional in-ear headphones often entail. Finally, consider the KDE250 if you want to experience true hi-fi sound, while still being able to hear ambient sounds from nearby.
• Look further if: you prize strict neutrality in tonal balance (the KDE250 sounds somewhat midrange-forward), or need a headphone that offers powerful, deeply extended low bass. Also look further if you need a headphone that offers high levels of noise isolation, as the KDE250 does not block out much noise.
• Ratings (relative to comparably-priced competition):
⇒ Tonal Balance: 7.5
⇒ Frequency Extremes: 6 (bass)/9 (treble)
⇒ Clarity: 9.5
⇒ Dynamics: 8
⇒ Comfort/Fit: 10
⇒ Sensitivity: 7
⇒ Value: 8.5
• Summing Up: Koss’ KDE250 offers what some listeners will regard as a compelling alternative to traditional in-ear headphones. The KDE250 is light, comfortable, and offers impressive openness and transparency, and it allows you to keep track of what’s going on in the room around you. Though not the last word in neutral voicing, the KDE250 offers a somewhat midrange-forward sound whose inherent clarity many will find irresistible.
Koss KDE250 Dual-Element Headphones
Accessories: 3 sizes of ear clips, carrying pouch with inner tray that serves as an earpiece holder and cable-winding spool
Frequency response: 40 Hz – 20kHz
Weight: Not specified
Sensitivity: 95 dB (input levels not specified)
Impedance: 16 ohms
Warranty: Limited Lifetime Warranty