| Form Factor | Headphone - Circumaural |
| Signal Path | Analog Hardware |
| Weight | 345 g (headphone only) |
| Frequency Response | 16-22000 Hz |
| Principle | open electrostatic Hi-Fi-stereo-headphone |
| Transducer | electrostatic |
| Sound coupling to the ear | "open-aire" principle, main support circumaural via acoustically open supporting ring and leatherette cushion at the head. Ear touching foam cushion without pressure. |
| Headband pressure | appx. 4.5 N (460 p) |
| Matching impedance | 4-8 Ω loudspeaker output |
| Sound pressure level at 5V | 103 dB (2.8 Pa) |
| Max. sound pressure level | 110 dB at 1 kHz (6.3 Pa) |
| Max. tolerable voltage applied | 25 VRMS (corresponding to 156 W at 4 Ω, transient condition) |
| Max. tolerable voltage applied | 35 VRMS (corresponding to 306 W at 4 Ω, continuous) |
| THD at 1000 Hz/110 dB | ≦ 0.1 % |
| Cable length headphone | 3 m |
| Cable length supply unit | 1.5 m |
| Dimensions HER 2000 | 75x65x184 mm (supply unit) |
| Weight supply unit | appx. 1600 g |
| Notes | Supply unit's model no.: HER 2000
Sennheiser's retrospective appraisal of their product:
"A further milestone followed when Sennheiser engineers for the first time combined the principle of open headphones with that of electrostatic transducer technology. Sennheiser’s launch of the unipolar 2000 model in 1977 caused a sensation in the audio world. Its principle was once again an innovation in audio technology. In the electrostatic transducer, a high voltage is applied to two mesh-like electrodes. As in a loudspeaker, this voltage causes a coated foil diaphragm to vibrate in time with the audio signal. This results in an extremely fine resolution and low total harmonic distortion. “Its frequency curve has a relatively deep curvature from 2 to 4 kHz. This is one of the reasons why these headphones generate an extremely spacious, detailed, transparent, airy and nevertheless powerful sound image in unprecedented quality," was how one audio magazine ‘Hifi-Stereofonie’, sang the praises of the new headphones." |
