Overview

The FiiO FD15 is a single dynamic driver in-ear monitor built around a 13.8mm driver with a magnalium (aluminum-magnesium alloy) diaphragm and a DLC gasket, covering a 10Hz–40kHz frequency range at 32Ω impedance and 112dB/mW sensitivity. The housing is machined from 316L medical-grade stainless steel using powder metallurgy sintering, weighing about 12g per earpiece. A 4-strand, 480-wire cable blending Furukawa monocrystalline copper and silver-plated copper terminates in an expanded MMCX connector with a swappable 3.5mm/4.4mm plug.

Simcoe Audio Video Insight

The FD15 ships with two swappable sound nozzles rather than one fixed tuning — the black nozzle sharpens treble detail, while the red nozzle leans into bass and vocal warmth. That gives you two distinct sound signatures from a single earphone, without needing separate EQ or a second pair.

• 13.8mm dynamic driver with magnalium diaphragm and DLC gasket
• 316L medical-grade stainless steel housing
• Two swappable sound nozzles for different tunings

Best for the FiiO FD15: start with the black nozzle if you want sharper treble detail, then switch to the red nozzle when you want warmer bass and vocals — both are included in the box.

More Details

Why It Wins

• 13.8mm Magnalium Driver: A large dynamic driver with a DLC gasket for detailed, controlled sound.
• Swappable Sound Nozzles: Black nozzle for clearer treble, red nozzle for enhanced bass and vocals.
• 316L Stainless Steel Housing: Medical-grade, powder metallurgy sintered construction.

What Makes It Different

Most single dynamic driver IEMs at this price lock you into one tuning. The FD15's swappable nozzle system lets you shift the sound profile toward treble clarity or bass warmth depending on the music or your mood, without buying a second earphone.

Technical Highlights

• 32Ω Impedance / 112dB/mW Sensitivity: Efficient enough for portable sources while still responding well to a dedicated amp.
• Expanded MMCX Connector: Detachable cable for easy replacement or upgrades.
• Swappable 3.5mm/4.4mm Plug: Matches both single-ended and balanced sources.

Buyers Guide

Who This Is For

• The Tuning Experimenter: Wants to adjust sound signature without buying multiple IEMs.
• The Detail-Oriented Listener: Will appreciate the treble-focused black nozzle option.
• The Bass and Vocal Fan: Can switch to the red nozzle for a warmer, more emotional sound.

Ideal Use Case

• Everyday Portable Listening: A durable stainless steel build for daily use.
• Genre-Switching Listeners: Swap nozzles to match different music styles.
• Desktop or Portable Amp Pairing: The 4.4mm plug option suits balanced sources.

What To Pair It With

• A Smartphone or DAP: Using the single-ended 3.5mm plug.
• A Balanced Portable Amp: Using the swappable 4.4mm plug.
• Both Included Nozzles: To match the tuning to the recording.

Alternative Options

The FD15 is a single dynamic driver IEM with swappable tuning nozzles. If you'd prefer a hybrid driver setup instead, FiiO's FH3 and FH11, already in our lineup, combine a dynamic driver with balanced armatures for a different take on detail and separation.