The IE 900 is the top of Sennheiser's in-ear line and uses a single 7mm TrueResponse dynamic driver rather than a multi-driver crossover design. The housing is machined from one piece of aluminium, anodised against corrosion, and made in Ireland. Three interchangeable cables cover 3.5 mm unbalanced, 2.5 mm balanced and 4.4 mm balanced.
Key features
A single 7mm TrueResponse driver
One full-range dynamic driver covers the whole band, so there is no crossover and phase coherence comes from the structure itself. Frequency response is 5 Hz to 48,000 Hz, with total harmonic distortion under 0.05% at 1 kHz, 94 dB.
X3R triple-resonator chamber
Three Helmholtz resonators sit inside the housing alongside the Vortex acoustic design, used to control high-frequency peaks and standing waves. This is purely mechanical acoustic treatment, with no electronic correction involved.
Three cables and Fidelity (+) MMCX
3.5 mm unbalanced, 2.5 mm balanced and 4.4 mm balanced cables are included, each 1.25 m and reinforced with para-aramid. The connector is a gold-plated Fidelity (+) MMCX, which locks in firmly for repeated cable swaps.
Aluminium housing and ear adapters
The one-piece precision-machined aluminium body ships with three pairs of silicone adapters (S, M, L) and three pairs of memory foam adapters (S, M, L), plus adjustable ear hooks, a carry case, a cable clip and a cleaning tool.
Specifications
| Item | Specification |
|---|---|
| Driver | 7 mm TrueResponse dynamic driver |
| Acoustic design | X3R triple-resonator chamber (Helmholtz resonators + Vortex acoustic design) |
| Frequency response | 5 Hz – 48,000 Hz |
| Impedance | 16 – 18 ohms |
| THD | < 0.05% (1 kHz, 94 dB) |
| Sound pressure level | 123 dB (1 kHz, 1 Vrms) |
| Cables | Three interchangeable: 3.5 mm unbalanced, 2.5 mm balanced, 4.4 mm balanced; 1.25 m, para-aramid reinforced |
| Connector | Gold-plated Fidelity (+) MMCX |
| Ear adapters | Silicone S/M/L; memory foam S/M/L |
| Housing | One-piece precision-machined aluminium, anodised, made in Ireland |
| Accessories | Carry case, cable clip, cleaning tool, adjustable ear hooks, signed certificate |
Who it's for
- Owners of portable players or desktop DACs with 4.4 mm or 2.5 mm balanced outputs.
- Listeners who want the coherence of a single dynamic driver, with no crossover seams to hear.
- Stage monitoring and studio work, where isolation and a secure fit matter.
- Who it's not for: anyone who wants plug-and-forget convenience. There is no Bluetooth, no noise cancellation and no microphone, and if the ear adapter does not seal, the bass falls apart. You need to be willing to try tips and match a source.
Warranty and delivery
International version · 10-day exchange if faulty · 100% brand new · Viewing by appointment at our Kwun Tong shop, see the warranty policy for details.
Non-TV items are delivered by SF Express (freight collect, paid by the customer), or collected at our Kwun Tong shop (free, 11:00–19:00). For other couriers or delivery to Macau, please WhatsApp us.
FAQ
Q: Can a phone drive them? A: At 16 – 18 ohms and 123 dB (1 kHz, 1 Vrms) they are sensitive, so a phone reaches volume easily. A noisy source will let you hear its hiss, so a clean DAC or player is worth using.
Q: Can I change the cable myself? A: Yes. The connector is a gold-plated Fidelity (+) MMCX, and three cables with different plugs are supplied in the box.
Q: How many ear adapters are included? A: Six pairs, silicone in S, M and L plus memory foam in S, M and L, along with adjustable ear hooks.