Sennheiser has made it their goal to achieve a transparent sound with no distracting peaks or troughs. This requires a clear separation of lows and mids. To ensure accuracy across this critical frequency band, these IEMs utilize an acoustic back volume, a small chamber within a chamber tuned to manage the slope and amplitude of the base lift. This controls the direction and overall volume of the 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.

The inherent compromises multi-driver systems require (phase issues and the resulting distortion in overlapping frequency bands) necessitated a single dynamic driver. To tune this driver correctly, Sennheiser designed a sophisticated system of three Helmholtz resonators and dubbed it the X3R.

The X3R is milled right into the solid aluminum housing of each earphone. Tiny channels eliminate resonance peaks, which, in less advanced products, would color the sound signature and alter the feel of your music. In addition, Sennheiser has fashioned a complex Vortex structure into the nozzle of each earphone. This swirls acoustic energy in problematic frequency bands to smooth out peaks.

In addition to outstanding sound, audiophiles appreciate durable products that are made to last. Here, the IE 900 excels. Gold-plated Fidelity+ MMCX connectors ensure perfect contact. Each termination is seated within a recessed, 4.8mm-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. Connect to practically any digital audio source with the 3.5mm stereo plug including headphone amps, laptops, and audio interfaces. Each pair of IE 900s also includes symmetrical 2.5mm and 4.4mm cables for plugging directly into hi-fi components with balanced outputs.

Working musicians rely on high-quality, form-fitting earphones known as personal monitoring systems. But Sennheiser believes the privilege of enjoying perfect live sound should not be the exclusive right of the performers of the world. So, they took the comfort and secure fit of professional solutions as inspiration for the IE 900.

Now you can enjoy a fit and quality that rival what artists who create your music experience. 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 experienced an amazing piece of music spoiled by a recurring bass note that happens to match the resonant frequency of your loudspeakers or headphones. It can happen with sibilance too. Such obvious deficiencies are eliminated 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.

Sennheiser built the IE 900 exclusively at their famed German manufacturing facility. Aluminum was the material of choice for this application. Well-suited to high-precision milling, it also extends an aesthetically pleasing, long-lasting home for electro-acoustic components. A five-axis CNC machine precision cuts each housing individually from a single block of aluminum. Once anodized, the housing is highly resistant to wear and corrosion. The drivers in each pair of IE 900s are matched during the automated manufacturing process to practically eliminate variance.