Description
The FiiO FD3 is a wired in-ear monitor built for listeners who want flagship-grade driver technology without stepping into flagship pricing. A single 12mm Diamond-Like Carbon (DLC) dynamic driver delivers fast transient response and minimal distortion, while the semi-open acoustic design with FiiO's patented air pressure relief technology keeps long listening sessions comfortable. At 32Ω and 111dB sensitivity, the FD3 pulls cleanly from phones, tablets, and portable players without needing a dedicated amplifier.
The FD3 inherits its acoustic prism from the flagship FD5, which eliminates high-frequency standing waves and improves sound wave diffusion for a more coherent presentation. The interchangeable sound tubes let you dial in your preference—red tubes emphasize bass while black tubes bring out treble detail. The aluminum-magnesium alloy shell with 2.5D film-coated glass faceplate feels premium at just 7 grams per unit. Headfonics reviewers describe the semi-open design as producing a wide soundstage for an IEM at this price, with a natural even-handed tonal balance that scales well with better sources.
Specifications
| Driver Type | 12mm DLC (Diamond-Like Carbon) dynamic driver |
| Magnetic Flux | 1.5 Tesla |
| Voice Coil | Ultra-fine copper-clad aluminum Japanese Daikoku |
| Frequency Response | 10Hz–40kHz |
| Impedance | 32Ω@1kHz |
| Sensitivity | 111dB@1mW |
| Max Input Power | 100mW |
| Connector | MMCX (detachable) |
| Cable | 4-strand, 120-core high-purity monocrystalline copper, ~120cm, 3.5mm TRS |
| Shell Material | 6-series aluminum-magnesium alloy, 5-axis CNC machined, hand polished |
| Faceplate | Celluloid panel with 2.5D film coating glass |
| Acoustic Design | Semi-open with FiiO patented air pressure relief technology |
| Acoustic Prism | Yes (front acoustic prism) |
| Sound Tubes | 2 interchangeable (red = bass-forward, black = treble resolution) |
| Weight | ~7g per unit (excluding cable) |
| Color | Black |
| Hi-Res Audio | Certified |
