The round started badly. A Neon had cut through mid on Ascent, the spike was planted in B-site, and three teammates were already dead on the minimap. What stopped the loss from feeling like a loss — what made it feel, briefly, like something closer to information — was a footstep. One footstep. Left channel, slightly forward, above the ambient hiss of the defuse timer. A flanking Sage, crouched in market. The Sennheiser HD 660S2 placed her there with such casual specificity that the counter-call felt less like a read and more like a fact.
That's an odd thing to say about a headphone that was not designed for this.
The HD 660S2 is an open-back, over-ear audiophile headphone. It has been on the market since late 2022 as the successor to the widely respected HD 660S, and it carries a street price of $599. The drivers are 38mm dynamic transducers tuned to a slightly warmer frequency response than its predecessor — Sennheiser pushed the low-frequency extension down to 8Hz and extended the top end to 41.5kHz, a number that matters mostly on paper but signals intent. Impedance sits at 300 ohms, which means it will not run properly from a phone headphone jack, or from most gaming PC front-panel outputs, or from any gaming headphone amplifier that cost under $80. It weighs 260 grams without cable. The earpads are soft, breathable velour. The headband is adjustable steel. It comes with two cables: a 3-meter balanced 4.4mm Pentaconn and a 3-meter unbalanced 6.35mm. Neither cable will plug directly into your motherboard's 3.5mm jack without an adapter you'll need to buy separately.
There is no microphone. There is no USB connection. There is no software. There is no lighting of any kind.
The case for it
Open-back headphones do something closed-back gaming headsets cannot: they stage sound outside the skull. The HD 660S2's soundstage is not artificially widened through DSP or virtual surround simulation — it is a physical property of the open driver housing, which bleeds sound in both directions and creates a listening space that feels lateral rather than cylindrical. In practice, in Valorant or CS2, this translates to directional audio that arrives with an address attached. Footsteps don't just come from
