IE 900
headphones
$1,700
Used market: $1,325*
Specifications
3 of 6 values have a recorded sourceExpert Audio Engineering Commentary
Tonal Profile
A single 7 mm dynamic with three Helmholtz resonators milled into the aluminium housing. Sennheiser states sensitivity the honest way for an in-ear — 123 dB at 1 Vrms — because volts are what a source actually delivers.
Amplification Warning
123 dB/V at 16 Ω is about 105 dB/mW. Every source on earth has enough voltage; the question is hiss. At this efficiency a few microvolts of output noise is audible, and a powerful desktop amplifier is usually the wrong answer.
What the datasheet actually says
Quoted verbatim from the manufacturer’s own page, with the date we checked it. We state what is printed, not what anyone intended by it.
«Impedance: 18 ohms»
The same page carries two impedances: «Impedance: 18 ohms» in the feature list and «Impedance 16 Ω» in the Specifications table below it. Neither states a condition. On the IE 200 sheet Sennheiser distinguishes «Impedance (without cable / with cable) 16 Ohm / 18 Ohm», which is exactly this pair of numbers — but the IE 900 page names no such condition, so the reader is left to guess which of the two the figure describes. We record the Specifications table value.
checked 8/5/2026* Estimated with the depreciation fallback (~78% retained value). · checked on 8/5/2026