How We Research
We compare products from their published specs and features; the verdicts below are our independent editorial opinions.
Updated: 2026-09-30 · 7 min read · Independent comparison
• Sennheiser IE 900 — biggest strength: a wired, audiophile-first design built around a German-made 7mm TrueResponse transducer, X3R technology and a triple-chamber absorber that pushes treble extension to a claimed 48,000 Hz.
• Sennheiser IE 900 — biggest trade-off: it is wired only, has no active noise cancellation (just passive sound isolation), and demands a source with a decent DAC or amp to get the most out of it.
• Bang & Olufsen Beoplay Eleven — biggest strength: true wireless convenience with Bluetooth 5.2, multipoint pairing, active noise cancellation, a transparency mode and an IP57 dust/water rating.
• Bang & Olufsen Beoplay Eleven — biggest trade-off: battery life is limited to roughly 6 hours per charge with ANC (about 20 hours with the case), and it tops out at a 20–22,000 Hz frequency range versus the IE 900's far wider spec.
• Pick the Sennheiser IE 900 if you listen analytically, own a good portable player or desktop DAC, and want a wired reference sound.
• Pick the Bang & Olufsen Beoplay Eleven if you want one pair of earbuds for the gym, the office and the airport without cables.
The IE 900 is a specialist tool, not a general-purpose earbud. Everything about the design points toward accuracy: a single 7mm TrueResponse dynamic driver made in Germany, matched during an automated process to keep unit-to-unit variance low, plus a membrane foil that the spec sheet says minimizes resonances and distortion. The triple-chamber absorber — three Helmholtz resonator chambers milled into the solid aluminum housing between the diaphragm and the nozzle — exists to kill the masking resonance peaks that color treble. In plain terms, this is a design meant to reveal what is actually in your recording, warts and all.
The connectivity story matters just as much. You get three para-aramid reinforced cables with gold-plated MMCX connectors: one single-ended 3.5mm and two balanced options at 2.5mm and 4.4mm. The recessed MMCX socket is rated for reliable attachment well past 500 cycles, which is the kind of detail you only appreciate after a couple of years of cable swaps. Sennheiser also throws in silicone and memory foam tips in three sizes, adjustable ear hooks, a cleaning tool, a cloth and a hard carry case. Note the 18-ohm impedance — low enough to be driven by most good sources, but this is still a wired IEM that rewards a clean signal chain.
Buy it if: you do most of your listening seated, you care about hearing the layers in a mix, you already own a player or DAC with a 2.5mm or 4.4mm balanced output, and you want a replaceable cable instead of a sealed wireless unit. Skip it if: you need noise cancellation on a plane, you hate dealing with cables, or you want something you can wear running in the rain. The IE 900 offers sound isolation, not ANC — that is a real limitation for commuting.
The Beoplay Eleven is the opposite philosophy: maximum flexibility in the smallest possible package. Each earbud carries a 9.2mm dynamic driver covering 20–22,000 Hz, and the housing mixes aluminum, polymer, silicone and hardened glass, which is where the "premium object" feel comes from. The touch surface on the glass handles playback, calls and the transparency toggle, so you rarely need your phone.
The practical features are what sell this pair. Bluetooth 5.2 with multipoint lets you stay connected to a laptop and a phone at once and switch between them without re-pairing. Active noise cancellation is described as the brand's strongest in an earbud, and the transparency mode flips you back to hearing your surroundings with a tap. The microphone inlet is larger and backed by a wind-filtering mesh, which is a genuinely useful upgrade for calls taken outdoors. Battery life is quoted at up to 6 hours with ANC on, extending to about 20 hours with the charging case, and the case itself supports wireless charging. A 1.5-hour charge time for the buds and 2.5 hours for the case is reasonable for the category.
Then there is durability. IP57 means dust protection plus resistance to sweat and water, so running in the rain or a hard gym session is within scope. The 32-ohm impedance and wireless-only design mean there is no cable to worry about and no amp to buy — you pair it and go. Buy it if: you want one pair for work calls, workouts and travel, you value ANC and multipoint, and you prefer the freedom of no wires. Skip it if: you are chasing maximum resolution, you dislike charging routines, or you need the balanced wired outputs that only the IE 900 offers.
• Best for critical, detail-first listening → Sennheiser IE 900. The X3R transducer, triple-chamber absorber and 5 Hz–48 kHz range are built for analysis, not background music.
• Best for commuting and flights → Bang & Olufsen Beoplay Eleven. Active noise cancellation beats passive isolation every time on a plane or train.
• Best for workouts and bad weather → Bang & Olufsen Beoplay Eleven. IP57 dust and water resistance is the deciding factor; the IE 900 is not rated for that.
• Best for home setups with a DAC or balanced player → Sennheiser IE 900. The included 2.5mm and 4.4mm balanced cables are wasted on a phone and brilliant on a dedicated player.
• Best for staying connected to two devices → Bang & Olufsen Beoplay Eleven. Bluetooth 5.2 multipoint handles laptop-plus-phone switching that wired IEMs simply cannot do.
• Best for long listening sessions away from a charger → Bang & Olufsen Beoplay Eleven, but keep expectations realistic: roughly 6 hours per charge with ANC, about 20 hours total with the case.
• Best for cable longevity and repairability → Sennheiser IE 900. The recessed MMCX connectors are designed to survive hundreds of attachment cycles, and the cable is detachable rather than sealed.
• Best for calls on the move → Bang & Olufsen Beoplay Eleven. The enlarged, wind-filtered mic inlet is purpose-built for voice pickup outdoors.
My Verdict
how to clean in ear headphones
Wipe the nozzles and housings with a soft dry cloth and clear any earwax from the tip openings with a small brush or tool. The Sennheiser IE 900 ships with a cleaning tool and cloth for exactly this, and both products use removable tips that can be taken off and rinsed or replaced. Clean tips regularly — clogged mesh is the most common cause of sudden volume loss.
how to fit in ear headphones
Start with the smallest tip that still seals, then work up until outside noise drops and bass feels full. The IE 900 includes silicone and memory foam adaptors in three sizes plus adjustable ear hooks, while the Beoplay Eleven includes silicone tips in four sizes plus a Comply foam pair. A proper seal matters more than tip brand — it is what makes both isolation and bass response work.
how to open in ear headphones
For the IE 900, "opening" means detaching the cable: the MMCX connectors pull free from the earpieces and are designed for repeated cycles. For the Beoplay Eleven, you open the charging case lid to remove the buds and pair them, and there is no user-serviceable opening beyond that. Do not try to prise open either earpiece housing — there is nothing inside meant for you to reach.
how to ear headphones
If you mean how to wear them correctly: the IE 900 goes in with the cable routed over the top of your ear and the hook adjusted for stability, which keeps the wire from tugging. The Beoplay Eleven is worn with the nozzle angled into the canal and the touch surface facing out, so taps register cleanly. Getting the orientation right is what keeps either pair from loosening during movement.
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