14 years ago, Sennheiser launched their HD 650 headphone, a well-regarded pair of over ear and open back headphones that definitely stood the test of time.

But after all of that time Sennheiser today announced the release of a brand new version of these headphones that have been named the Sennheiser HD 660 S, which retains a similar open-back design to the original 650s.

They also feature a slide-adjustable headband with two large pads on either side.

They are slightly different in terms of their finish, which is now a matte black with anthracite.

The real difference between the new HD 660 S and the old HD 650 can be found on the inside.

Sennheiser has fitted the headphones with a new transducer, which they say has a lower harmonic distortion and allows the headphones to produce an even and more natural, uncoloured sound.

Sennheiser has hand-matched and tested the left and right ear cup of each headphone in order to produce a near identical sound within a tolerance of _/- 1dB.

While they are best suited to a high-end system, Sennheiser also says that the 650 S sound work with smartphones.

You can pick them up today in the UK for £429.99 or in the US for $499.95.

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