HD 660S' predecessors, the HD 650 and HD 600, set new standards for audiophile headphones with their engaging signatures and liquid-smooth response. The HD 660S transcends the best of that history with its remarkable speed and effortless instrument reproduction, even at the extremes of the frequency spectrum. The HD 660S is equipped with an all-new transducer and specially ventilated drive unit, delivering the revealing details audiophiles demand without sacrificing the engaging dynamics that make music so enjoyable.
It only takes one listen to understand why the HD 660S is so special. Thousands of listening sessions later, its purpose becomes even clearer. Open-back ear cups paired with a new transducer designed for the modern audiophile produce the sound you hear each time. Its rapid response makes it perfect for reproducing those frequency-stretching recordings with confidence. With an aluminum voice coil, the 38mm diaphragm offers an ultra-quick impulse response across the board. This activation and rest behavior allows the brain to communicate tonal and spatial characteristics precisely.
A steel mesh found on the HD 660S drive unit has an interesting design, but most impressive performance. A ventilated driver offers dependable air displacement control to reduce turbulence. Thus, diaphragm travel is pure, letting the music-and only the music-shine in a perfect balance of integrity and expression. This steel composition allows for much tighter production tolerances, resulting in remarkably consistent characteristics in every HD 660S produced. Together with the open-back earcups, the sound emanating from each transducer is completely free to expand, just as it would in nature.
Today’s audiophile has more component choices than ever. We optimized the HD 660S for efficiency on a wider range of devices to accommodate the varying levels of power present in output amplification circuitry. At 150 ohms, the HD 660S is the perfect partner for dedicated amplifiers, A/V receivers, and digital audio players (DAPs)—the magnet is more powerful than its predecessors, and thus easier to drive regardless of how your setup changes over time.
Every HD 660S we produce has experienced a matching regimen to mate each transducer from our Ireland manufacturing facility to its opposite-channel counterpart. These tolerances are extremely narrow and when bolstered by automated assembly processes, ensure that your HD 660S experience is consistent with those all over the globe. We designed it with thoughtful, lightweight materials invisible to the acoustical system without sacrificing the durability needed for daily, all-day use. With a never-ending supply of music to consume, we wanted every touch point to be soft, luxurious, and durable for those extended listening sessions.
We packed your HD 660S with a versatile set of essential cables, each one impedance-matched with ultra-low capacitance. The ¼-inch / 6.3mm stereo connector offers the audiophile-standard plug for connection to devices such as headphone amplifiers and A/V receivers, digital audio players, analog gear, and more. A balanced, 4.4mm connector opens a pathway to a newer generation of balanced output devices (headphone amplifiers, digital audio players, etc.) that embrace this compact plug’s superior stability over time. A balanced headphone setup offers an even lower noise floor with great dynamic range when connected to balanced source/amp circuit outputs. The listener will thus experience a wider soundstage, tightly controlled transients and impossibly-clear instrument separation. Each cable is 9.8 feet / 3m long to accommodate unencumbered listening on gear deep within your shelves, or favorite listening chair, and a flexible adapter is included to reduce the 6.3mm to 3.5mm. An optional balanced cable (CH 650 S) is sold separately for simplified connection to 4-pin XLR jacks.