Sennheiser HD660S and IE800S high-end headphones and earphones

Of course, you can duck into any electronics chain store and pick up moderately priced Sennheiser ear-wear. But the company’s fame rests largely on its high-end gear. But the HD660S and IE800S are for music lovers to admire.

The HD660S and IE800S are not inexpensive models. Although they do not seek to challenge Sennheiser’s $55K Orpheus model in the pricing stakes. But they are for people happy to make a serious investment in their personal listening.

Sennheiser HD660S

The new Sennheiser HD 660S fit exactly into Sennheiser’s tradition. It began by manufacturing high quality ‘open’ headphones. And that’s what these are.

Traditional headphones used a closed design. The speakers are in plastic cups (or Bakelite or goodness knows in days gone). They seal your ears from the outside world.

Conversely, Sennheiser’s ‘open’ models use a grille at the back, so there is no air cushioning of the transducer. That often produces a more responsive sound, but at the cost of less isolation from external sounds. It also makes the headphones more audible to others.


Back to the HD660S.

These use an open design. Replacing the HD650, they feature a new transducer that ‘delivers lower harmonic distortion for an even more natural, lifelike audio experience’. To ensure excellent left/right balance and volume the transducers are matching pairs.

The new models also feature a lower impedance: 150 ohms, compared to the HD650 300 ohms. That makes them an easier drive for portable audio players, although typically one would use high-end players with these kinds of headphones.

And, to make things clear, these are wired, passive headphones. None of that Bluetooth stuff, nor any electronic signal processing.

Another change: while they can work in the usual way with a 6.35mm three-conductor stereo plug – 1/4″. They also have a 3.5mm stereo plug adaptor. And they support “balanced” operation with a 4.4mm Pentaconn plug.

Huh? Okay, you have two channels of sound.

Regular headphone connectors use a signal lead to each driver plus a common, combined lead to complete the circuit. That common lead often takes the form of a woven “shield” in the cable to protect the signal leads from electrical interference. So that’s three conductors in total.

Balanced headphone leads use four or five. The signal lead and the “return” signal lead are separate for the left and right channels, while the shielding if used, is a fifth, completely different, circuit. All that reduces crosstalk between the left and right channels and better protect both channels from external electrical interference.

And, yes, a number of high-quality portable music players, and not so portable headphone amplifiers, now support balanced headphones.

Sennheiser IE 800 S plugs: 2.5mm balanced, left; 3.5mm standard, middle; 4.4mm Pentaconn, right

The HD 660 S are over-ear models and come with replaceable ear cushions – something that I was recently thankful for with my own twenty-year-old Sennheiser HD 535 headphones.

Sennheiser rates their frequency response – with -10 decibel endpoints – at 10 to 41,000 hertz, and specifies their distortion at less than 0.04% at 1kHz and 100dB output. That’s an astonishing specification, more akin to what you see from high-quality electronics, not headphones.

The Sennheiser HD 660S headphones will be available in November 2017 for $799.95.

Sennheiser IE800S earphones

Sennheiser’s new high-end earbuds are the Sennheiser IE800S. Price? Sit down first. Ready? $1599.95. (Yes, sixteen hundred dollars, near enough.)

That price is such a surprise because we’ve come to think of earbuds as cheap, almost disposable, ways of listening to music from portable devices. But there’s actually a good reason why high-quality earphones might be better. Because the sound goes directly into your ear canal it removes a lot of variables.


These earphones are for use with high-end portable music players from Pioneer Electronics, Astell & Kern and FiiO. Many of which support balanced earphones and headphones. Yes, that again.

They have a standard 3.5mm three-conductor plug (no volume or play/pause control on these), and 4.4mm balanced Pentaconn and 2.5mm balanced plugs.

The earphones come with six tips: small, medium and large in both silicon and “Comply”, which is a kind of memory foam. I’m becoming more of a fan of Comply as I’ve continued to use a pair of Bluetooth earphones with those tips.

“Engineered and hand-crafted in Germany”, the IE800S earphones use refined 7mm transducers. They have a closed design with a “dual-chamber absorber” to remove unwanted resonances.

The Sennheiser IE 800 S earphones have a rated frequency response of 5 to 46,500 hertz. They deliver up to 125 decibels. Total harmonic distortion lis less than 0.06% for 94dB of output,. Impedance is friendly to portable devices, at 16 ohms. They come with a leather carry case.

Because these are close to perfect for their respective use and occupy audiophile niches in Sennheiser’s line-up they deserve a 5/5. Yes there are competitive brands and products – they probably deserve similar ratings.

You can read other Sennheiser reviews here

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