Sennheiser IE 900 Audiophile Earbuds 
 
The precision-manufactured aluminum housing of the IE 900 faithfully protects the dynamic TrueResponse transducers at the heart of Sennheiser’s innovative X3R technology. Experience the peak of German audio engineering and manufacturing with earphones that deliver only the purest, most natural sound.
 
The IE 900 — goodbye to tradeoffs
High-fidelity recordings are pieces of art. Just as with a valuable painting, it would be a disgrace to allow damage during transport. The IE 900 reveals the true potential of any recording. If it’s a masterpiece, you’ll hear it. Brilliant, sparkling treble — with no trace of sibilance. Powerful lows without creating muddy mids. An uncanny ability to resolve fine detail — alongside warmth and comfort for extended sessions. 
All these qualities derive from inspired feats of engineering. Take Sennheiser’s trusted 7 mm transducer, for instance. We’ve made it just that much better for the IE 900. Or the all-new X3R triple-chamber absorber technology milled right into the solid aluminum core with its downstream acoustic vortex. Taken together, these innovations deliver a unique level of balance and transparency — so you never have to compromise again.
 
Explore every last detail 
Considerable effort goes into capturing the finest nuances of a musical performance. Re-living the creativity and texture recorded in the studio or concert hall can be a source of great pleasure. But only if the listener’s playback equipment allows. Our German-engineered and manufactured TrueResponse driver ensures exceptionally natural reproduction. A large part of its very precise transient response comes from the unique combination of materials in the diaphragm together with its high inner dampening. So when the signal stops, the sound stops too. This is how the IE 900 can reveal details in tracks you thought you knew inside out. 
But the only thing that counts is what you, the listener, hear. The tonality of each instrument becomes clearly audible. And it’s not just the skills of the musicians that the IE 900 reveals. Even the acoustic properties of the room gain a new presence. Instead of remaining on the surface, you can now dive deep into complex passages — all while immersed in a breathtaking sound stage.
 
A new level of clarity
In developing the IE 900, we faced a fundamental choice. The inherent compromises multi-driver systems require (phase issues and the resulting distortion in overlapping frequency bands) made the decision easy. There would be a single dynamic driver only — of the highest quality, of course. 
To get exactly the sound we were looking for, we designed a sophisticated system of three Helmholtz resonators — the X3R. It’s milled right into the solid aluminum housing of each earphone. These tiny channels eliminate resonance peaks which, in less advanced products, 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.
 
An acoustic back-volume establishes balance
Our goal was to achieve a transparent sound with no distracting peaks or troughs. One thing this requires is clear separation of lows and mids. To ensure accuracy across this critical frequency band, we’ve employed what is known as an acoustic back volume. It’s a small chamber within a chamber we have tuned to manage the slope and amplitude of the base lift. The way the back volume helps achieve such a clear and natural sound signature is by controlling the direction and overall volume of air as it moves through the transducer system. What you hear is a pleasantly disciplined bass and mid-range experience. Unpleasant resonances and listening fatigue vanish in this small space with a big effect.
 
It pays to have good connections
In addition to outstanding sound, audiophiles appreciate durable products that are made to last. Here as well, the IE 900 excels. 
Gold-plated Fidelity+ MMCX connectors ensure perfect contact. Each termination is seated within a recessed, 4.8 mm-wide socket below the surface of the housing, providing strain relief. The cables themselves are para-aramid reinforced to withstand many thousands of bend cycles. But they don’t have to when protected in the included serialized case. 
Connect to practically any digital audio source with the 3.5 mm stereo plug including headphone amps, laptops, and audio interfaces. Each pair of IE 900s also includes symmetrical 2.5 mm and 4.4 mm cables for plugging directly into hi-fi components with balanced outputs. Because when you’re looking for the most natural and immersive sound, every detail matters.
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What's in the box?
    • IE 900 in-ear headphones
    • Balanced para-aramid reinforced cable with 2.5mm connector
    • Unbalanced para-aramid reinforced cable with 3.5mm connector
    • Balanced para-aramid reinforced cable with 4.4mm connector
    • 3 pairs of silicone ear adapters (S, M, L)
    • 3 pairs of foam ear adapters (S, M, L)
    • Premium carry case with metal serial no. plate
    • Cable clip, Cleaning tool & Cleaning cloth
    • Presentation box with signed customer certificate & User manuals
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Features
• New benchmark in portable audio
• Ultimate precision & craftsmanship
• Made in Germany
• X3R technology: TrueResponse transducer combined with three Helmholtz resonator chambers and acoustic vortex 
• Precision-milled and anodized aluminum housing
• Hand-assembled at Sennheiser´s headquarters
• Gold-plated Fidelity (+) MMCX connectors for improved stability
• Choice of para-aramid reinforced cables (2.5 mm, 3.5 mm, 4.4 mm) 
• Adjustable ear hooks and choice of ear adapters including memory foam
• Frequency response: 5 Hz - 48,000 Hz
• THD: 0.05% (1 kHz, 94 dB)
• Impedance: 16 ohms