Philips Fidelio X3 Open-Back Headphones: features, specs and who they suit

The Philips Fidelio X3 (model X3/00) are wired, over-ear, open-back headphones aimed at critical listening, recording and mixing. Philips describes the sound as wide, natural and uncoloured. They come with detachable cables for both a headphone amplifier and an everyday phone or laptop.

What open-back means for the sound

In a closed-back headphone the ear cup seals in the sound. An open-back design lets air and sound pass through the outside of the cup. Philips says this removes the air-pressure build-up behind the diaphragms, which it credits for a spacious, immersive sound. The outer grille uses acoustically transparent Kvadrat speaker fabric.

The trade-off is leakage. Open-back headphones typically let outside noise in and let others nearby hear what you are playing. They are usually chosen for quiet rooms, studio work and home listening, not for commuting or shared offices.

The 50 mm drivers

Each side has a 50 mm multi-layer polymer diaphragm with a damping gel. Philips says the tuning gives detailed highs, a full and smooth midrange and bass that is impactful without overpowering. Larger diaphragms can move more air, and damping layers are generally used to control unwanted resonance. How that sounds is always a matter of personal taste, so listen if you can.

Reading the specifications

• Frequency response: 5 to 40,000 Hz. Human hearing is usually quoted as 20 Hz to 20 kHz, so the range extends well beyond it. The Hi-Res Audio certification refers to this wider bandwidth when the source supports it.
• Impedance: 30 ohms. This is fairly easy to drive, so a phone or laptop can work, though a dedicated amplifier may give more headroom.
• Sensitivity: 100 dB at 1 mW. Higher sensitivity means a given power produces more volume.
• Maximum power input: 500 mW.
• Weight: 13.4 oz (about 380 g).

Cables and connections

Two detachable 3 m oxygen-free cables are included, one balanced and one unbalanced. Balanced cables suit amplifiers with a balanced output; the unbalanced cable suits standard headphone outputs. A 3.5 to 6.3 mm adapter and a cable clip are also in the box. Detachable cables are easier to replace if one is damaged.

Comfort and materials

Philips says the headband is covered in black Muirhead Scottish leather, sourced responsibly, and describes the headphones as feather-light. Comfort depends on head shape and how long you wear them, so it is worth checking fit before long sessions.

Who they suit

They suit people who listen at a desk or in a dedicated room, home-studio users who want an open sound for mixing, and anyone building a wired setup with a headphone amplifier. They are not wireless and have no microphone or noise cancelling.

What to check before you buy

• Your environment: open-back headphones leak sound both ways.
• Your source: confirm it has a headphone output, or use an adapter or amplifier.
• Balanced output: only needed if your amplifier has one; otherwise use the unbalanced cable.
• Fit and comfort: consider head size and whether you wear glasses.
• Upkeep: ear pads and cables are typically the parts that wear first; check whether replacements are available.

The short version

• Wired open-back over-ear headphones with 50 mm multi-layer drivers.
• 5 to 40,000 Hz response, 30 ohm impedance, 100 dB sensitivity.
• Detachable balanced and unbalanced 3 m cables, plus a 6.3 mm adapter and clip.
• Leather-covered headband; 13.4 oz.
• Best in quiet spaces, not for commuting.

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