Sennheiser IE 900 – Wired In Ear Earphones Headphones

Sennheiser IE 900 – Wired In Ear Earphones

For the most sophisticated audiophiles, the search for the ultimate sound is a ceaseless quest for perfection. Inspired by this passion, the IE 900 is the flagship of Sennheiser's in-ear headphone range, setting new standards in audio fidelity. From the exquisite one-piece aluminum housing precision-milled from a single block of high-quality aluminum, to an improved version of the acclaimed 7 mm XWB transducer, to the conductive properties of the sound channel — every aspect was considered to make Sennheiser's extensive acoustic know-how audible in these in-ears. The new acoustic design of the TrueResponse transducers features an enhanced voice coil optimizing high-frequency performance for brilliant, natural sound, while natural resonances and harmonic distortions are minimized by an optimized membrane foil. The result is an exceptionally natural sound reproduction to satisfy even the most discerning audio enthusiast.

• Wired, in-ear, closed
• 7 mm extra-wideband (XWB) TrueResponse dynamic transducer with enhanced voice coil
• X3R triple-resonator chamber technology with acoustic Vortex
• Frequency response: 5 Hz – 48,000 Hz
• Impedance: 18 Ω (per instruction manual); 16 Ω (per product page)
• One-piece aluminum housing, precision-milled on five-axis CNC, anodized
• Three cables included: 2.5 mm balanced, 3.5 mm unbalanced, 4.4 mm balanced, para-aramid reinforced, 1.25 m
• Weight: 4 g per earphone (without cable)
• Developed in Germany, manufactured in Tullamore, Ireland
• 2 Year Warranty

Highlights & Key Technologies

X3R TrueResponse Transducer Technology
At the heart of the IE 900 is the 7 mm extra-wideband (XWB) TrueResponse dynamic transducer — an improved version of the acclaimed driver found across the IE series. The new acoustic design features an enhanced voice coil that optimizes performance at high frequencies for brilliant, natural sound reproduction, and natural resonances and harmonic distortions are minimized by an optimized membrane foil. To achieve the IE 900's transparent sound with no distracting peaks or troughs, Sennheiser designed an all-new system of three Helmholtz resonators — a crucial element in the X3R technology — milled directly into the solid aluminum housing of each earphone. These tiny channels eliminate resonance peaks that can color the sound signature and alter the feel of your music. In addition, a complex structure in the nozzle of each earphone — the Vortex — swirls acoustic energy in these frequency bands to smooth out peaks. The IE 900 delivers brilliant, sparkling treble with no trace of sibilance, powerful lows without creating muddy mids, and an uncanny ability to resolve fine detail alongside warmth and comfort for extended sessions. Total harmonic distortion is less than 0.05% (1 kHz, 94 dB).

Acoustic Back Volume
To ensure accuracy across the critical low and mid frequency bands, Sennheiser employed an acoustic back volume — a small chamber within a chamber tuned to manage the slope and amplitude of the bass lift. The back volume controls the direction and overall volume of air as it moves through the transducer system, achieving a pleasantly disciplined bass and mid-range experience. Unpleasant resonances and listening fatigue vanish in this small space with a big effect.

One-Piece Aluminum Housing
Each IE 900 housing is precision-cut from a single block of high-quality aluminum using a five-axis CNC machine. The use of aluminum was a clear choice: well-suited to high-precision milling, it provides an aesthetically pleasing, long-lasting home for the electro-acoustic components. The X3R resonator chambers and channels are milled directly into the solid aluminum core as part of the manufacturing process. Once anodized, the housing is highly resistant to wear and corrosion. The earphone housings are milled from metal blocks, and as a result, the first skin contact can cause irritation for a short moment at very cold or warm temperatures.

Fidelity+ MMCX Connectors & Cables
The IE 900 features gold-plated Fidelity+ MMCX connectors, each seated within a recessed 4.8 mm-wide socket below the surface of the housing for strain relief and greater stability. Three para-aramid reinforced oxygen-free copper (OFC) cables are included as standard, each approximately 1.25 m in length: a 2.5 mm balanced (4-pin) cable, a 3.5 mm unbalanced (3-pin) cable, and a 4.4 mm balanced (5-pin) cable. The cables feature TPU-coated adjustable ear hooks for over-the-ear routing, providing lightweight wearing comfort and significantly reduced structure-borne noise compared to standard cables. The cables are designed to withstand many thousands of bend cycles.

Comfort, Fit & Identification
The IE 900 packs big sound into a small, ergonomic package weighing approximately 4 grams per earphone without cable. Individually adjustable ear hooks and a choice of ear tip adapters ensure a perfectly secure fit. Silicone ear adapters (S, M, L) and Visco memory foam ear adapters (S, M, L) are included, with two lock-in positions for tuning the fit. The right earphone is marked with "R" and an additional red ring, while the left earphone is marked with "L" and additional tactile dots for correct identification.

Manufacturing & Quality
The IE 900 is developed in Germany and manufactured at Sennheiser's state-of-the-art audiophile manufacturing plant in Tullamore, Ireland — the same facility that builds the revered HD 800 S, HD 820, HD 650, and HD 600. The tightest production tolerances apply: every transducer is fully tested twice — first individually and then together after the right and left earphones have been hand-selected in pairs. The drivers in each pair are matched during the automated manufacturing process to practically eliminate variance, resulting in a transparent soundstage with no gaps or holes. A premium carry case, signed certificate of authenticity, and presentation box are included.

Details & Specifications

MODEL INFORMATION
Model: IE 900
Article number (SKU): 508949

TRANSDUCER
Transducer principle: Dynamic, Extra Wide Band (XWB)
Transducer size: 7 mm
Acoustic technology: X3R triple-resonator chamber with Helmholtz resonators and acoustic Vortex
Ear coupling: In-ear, closed
Frequency characteristic: Diffuse-field equalized
Voice coil: Enhanced (optimized high-frequency performance)
Membrane: Optimized foil (minimized resonances and distortion)
Maximum value of the static magnetic field at the surface: 1.3 mT

PERFORMANCE
Frequency response: 5 Hz – 48,000 Hz
Impedance: 18 Ω (per instruction manual); 16 Ω (per product page)
Sound pressure level: 123 dB at 1 kHz, 1 Vrms
Total harmonic distortion: < 0.05% (1 kHz, 94 dB)
Attenuation: –26 dB (per instruction manual); –10 dB (per product page)

HOUSING
Material: High-quality aluminum, one-piece construction
Fabrication: Precision-milled from a single block on five-axis CNC machine
Surface treatment: Anodized

CABLE & CONNECTIVITY
Cable: Oxygen-free copper cable (OFC), para-aramid reinforced
Cable length: 1.25 m (each cable)
Ear hooks: TPU-coated, adjustable
Connector (earphone side): Fidelity+ MMCX, gold-plated, recessed (4.8 mm socket)
Included cables:
– 2.5 mm stereo jack plug, balanced, 4-pin, gold-plated
– 3.5 mm stereo jack plug, unbalanced, 3-pin, gold-plated
– 4.4 mm stereo jack plug, balanced, 5-pin, gold-plated

PHYSICAL SPECIFICATIONS
Weight: Approximately 4 g per earphone (without cable)
Ear adapters included: Silicone (S, M, L) and Visco memory foam (S, M, L), 2 lock-in positions

ENVIRONMENTAL
Operating temperature: –10°C to +55°C

INCLUDED ACCESSORIES
IE 900 in-ear earphones (left and right)
Balanced para-aramid reinforced cable with 2.5 mm connector
Unbalanced para-aramid reinforced cable with 3.5 mm connector
Balanced para-aramid reinforced cable with 4.4 mm connector
Silicone ear adapters (S, M, L) — 3 pairs
Visco memory foam ear adapters (S, M, L) — 3 pairs
Premium carry case
Cable clip
Cleaning tool
Microfiber cloth
Presentation box with signed certificate of authenticity and instruction manual