Sennheiser IE 900 In-Ear Headphones

The arrival of Sennheiser’s new audiophile in-ear flagship, the IE 900, also marks the launch of the German audio company’s brand new X3R system. German-made and engineered, this deceptively small transducer system delivers the coherent, artifact-free “Sennheiser Sound” found in full-size headphones up to 8 times larger in size.

Instead of a multi-driver system that introduces phase incoherence and unwanted distortion, Sennheiser has improved the one-driver principle.

Developed with an audience of hifi sound enthusiasts in mind, the IE 900 makes even the subtlest nuances of sound audible.

This reproduction of a wide frequency range with low distortion is the result of Sennheiser ́s one-driver principle and the development of their X3R system, a refined version of the company’s own, in-house developed and produced, 7 mm TrueResponse transducer.

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.

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.

Our German-engineered TrueResponse driver ensures exceptionally natural reproduction.

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 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 single dynamic driver only — of the highest quality, of course.

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 — a crucial element in the X3R technology - milled right into the solid aluminum housing of each earphone. These tiny channels eliminate resonance peaks which 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.

To ensure accuracy across this critical frequency band, we’ve employed what is known as an acoustic back volume.

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 bass 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.

We build the IE 900 at our state-of-the-art audiophile manufacturing plant in Ireland.

It's the same facility that builds the revered HD 800S, HD 820, HD 650 and HD 600. The use of aluminum was a clear choice: well-suited to high-precision milling, it also provides an aesthetically pleasing, long-lasting home for the electro-acoustic components. A five-axis CNC machine precision cuts each housing individually from a single block of aluminum. The result is truly a work of art. Once anodized, the housing is highly resistant to wear and corrosion — music to the ears of any daily listener. The drivers in each pair of IE 900s are matched during our automated manufacturing process to practically eliminate variance. The result? A transparent soundstage with no gaps or holes.

We took the comfort and secure fit of these professional solutions as inspiration for the IE 900.

Working musicians rely on high-quality, form fitting earphones known as personal monitoring systems. But we felt the privilege of enjoying perfect live sound should not be the exclusive right of the performers of the world. So, we took the comfort and secure fit of these professional solutions as inspiration for the IE 900. Now you can enjoy a fit and quality that rival that experienced by the artists who create your music. Included with the IE 900 are silicone ear adapters and three elastic foam ear adapter sets in three different sizes. They adapt to the natural shape of your ear for a tailored fit. We’ve all been there: an amazing piece of music spoiled by a recurring bass note that happens to match the resonant frequency of your loudspeakers or headphones. Or rough treble sibilance that makes longer sessions uncomfortable. Such obvious deficiencies are unthinkable with the IE 900. All you will hear is precisely what the artist intended. They’re perfect at your desk, on a train, or taking a walk through the woods. Never have a listening session spoiled by your earphones again.

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.