The KDX Gold’s’ superior tonal balance hinges, first, on the fact that the ‘phones produce bass that not only sounds taut and offers good pitch definition, but that also has plenty of foundational weight and punch (something the Silvers don’t do nearly as well). In turn, the Gold’s provide midrange that is at once revealing, yet also smooth and well balanced—never overly prominent or pushed forward in the mix (as is the case with the Silvers). As a result, the Gold’s midrange is more evenly matched with its bass and highs. While some might miss the Silver’s arguably more vivid and evocative midrange-forward sound, others will appreciate the Gold’s greater warmth, smoother sound, and generally more neutral balance. The only complaint, again, might be that the Gold’s more laid-back mids tend to give them a more “distant” and less “up-close-and-personal” presentation.
At the treble end of the audio spectrum the KDX 300 Gold’s offer good though perhaps not class-leading measures of high frequency definition and focus. Interestingly, some listeners initially perceive the Gold’s highs to sound a little recessed, and least relative to the KDX Silvers. I think this perception arises because the Silver’s region of midrange prominence extends up pretty high, making the Silvers seem brighter and more defined at first. But if you listen to the Golds’ highs in isolation (on delicate high percussion instruments, for example) you’ll discover they are in fact surprisingly clear and refined.
Overall, the KDX 300 Golds sound similar to, but a bit darker and just a touch less transparent than one of the strongest competitors in this class: namely, the NuForce NE-700X. Compared to the NuForce, the KDX Silvers sound noticeably more midrange-forward, with significantly less powerful bass.
To learn how the sonic characteristics I’ve sketched out above play out on real-world music, it may be instructive to describe what happened when I played two good recording through the Golds—recordings that took full advantage of the headphone’s balanced, full-range sound.
First up is “If You Love Me Like You Say” from blues guitarist Debbie Davies’ album Holdin’ Court (Little Dipper). This track features Ms. Davies playing an aggressively howling Fender Stratocaster guitar while supported by a razor-sharp, hard driving, and punchy-as-all-get-out rhythm section. The Gold’s did a beautiful job with the midrange utterances of the Strat, showing how its sustained notes often expand into a full on “howl” or “cry.” Similarly, the Gold’s powerful low-end captured the almost locomotive-like propulsive drive of the electric bass and the deep, thunderclap-like smack of the kick drum-- qualities that, with some competing earphones, tend to get lost in translation. On cymbals and the very upper end of the Strat’s voice, the Gold’s sound perhaps a little too subdued, but not badly so.
Next, let’s consider “So Sorry” from Feist’s The Reminder (Cherrytree/Interscope). On this song, where Feist’s vocals are for the most part supported only by an acoustic bass and guitar, plus occasional keyboard passages, the inherent smoothness of the Golds really came into its own. Feist’s voice is an interesting one, in that it rides right on that fair/foul line between sounding breathy, intricate, and expressive on one hand, yet can, on the other hand, sound occasionally brittle, glassy, and edgy—and thus become off-putting. On “So Sorry”, however, the Gold’s’ inherent smoothness enabled them to reveal the beauty and mystery that characterize Feist’s vocals at their best, while minimizing any tendency toward roughness, edginess, or glare. The acoustic bass sounded great, too, in large part because the KDX 300 Gold’s superior mid-bass weight, which give the sound of the bass while giving it vital body and depth.
Consider this product if: you want a well-made and sensibly priced in-ear headphone that offer quite well balanced sound and a good balance of sonic sophistication, smoothness, and refinement from top to bottom. While not necessarily a spectacular performer in any one area, the Gold is one of those ‘phones that wins you over by doing most things well (its sonic sins are mostly those of omission).
Look further if: you want a headphone that draws you into the music through a more vivid and intense midrange-forward sound (if these are your tastes, you might prefer Koss’ slightly less expensive KDX 200 Silver model).
Ratings (relative to comparably-priced competition):