One of the signature examples of excellence in the pro audio and audiophile game has been the HD series from Sennheiser. From the HD 600 to the HD 660s, these popular open-back headphones have been a staple for critical and casual listening. Now, Sennheiser looks to give an update to one of its established models, the HD 660s. The HD 660S2 is a revision to the HD 660s, updating its tuning and other specifications to reestablish the 660s as an essential audiophile headphone.
The HD 660S2 won’t do away with what makes the original a great headphone. Spatial positioning, musical clarity, and detail will remain a prominent part of this revision. What Sennheiser really looks to add with the 660S2 is subtle timbral differences in the low and high frequencies. With these changes in tone, Sennheiser has also updated specific components within its driver. A new ultra-light aluminum voice coil minimized the weight of the driver while giving the 660S2 an impedance of 300 ohms, much like their HD 600 and 650 headphones. Sennheiser has also reportedly implemented a new airflow structure meant to minimize distortion even further, while also eliminating obstructive artifacts.
Specs
| Transducer | Dynamic, open |
| Transducer size | 38 mm |
| Frequency response | 8 Hz – 41,500 Hz |
| Impedance | 300 Ω |
| Sound Pressure Level (SPL) | 104 dB (1 V) |
| Total Harmonic Distortion (THD) | < 0.04% (1 kHz, 100dB) |
| Style | Over-ear |
| Weight | 260 g |
| Adapter | 6.3 mm (1⁄4 inch) to 3.5 mm |
| Connector | 6.3 mm (1⁄4 inch) jack plug, 4.4 mm balanced plug |
| Cable length | 1.8 m |
| Magnetic field | 2.5 mT |
The Sennheiser HD 660S2 is available to pre-order at Audio46.
