Specs Driver: 10mm single dynamic driver (no fancy beryllium, LCP, CNT, or DLC diaphragm here) MMCX connector Impedance: 32ohm Sensitivity: 108dB/mW@1kHz
Fiio JD7 does sound Harman-like, particularly in the placement and clarity of the midrange. However, Fiio has made a few sensible adjustments to make the midrange rich, smooth, clear, and transparent.
Firstly, they fill in the 250Hz dip of the Harman target, giving music notes appropriate weight. As a result, male vocals such as Andrea Bocelli’s in Besame Mucho are rich and emotive, without becoming boomy, an undesirable effect of many bass-boosted IEMs produce. Cellos sound rich and full-bodied with spot-on timbre. For instance, when I listen to the Goldberb Variations arranged for Cello, Violin, and Viola, there was no confusion between three instruments.
Secondly, Fiio flattens the ear gain peak at 3kHz. As a result, the midrange is pulled away from you, like the singer takes just a half step away. This tuning helps avoid the usual shoutiness and gives the stage extra depth.
Finally, Fiio dips the 5-6kHz region about 3dB. This tuning choice surprises me because it is rare and not how Fiio usually tunes their IEMs. Why does dipping 5kHz matter? This region is also known as “presence” because it emphasises note attacks and increases the illusion of clarity. A dip in this region can make musical phrases smoother. For example, when I listen to Bach’s violin sonatas and partitas by James Ehnes, the sounds of the bow catching strings are not boosted to sound like ice-picks. When singers reach high notes, they don’t sound harsh and strident either. As a result, you can turn the volume a couple notches higher than usual, making the bass and treble air pop.