{"product_id":"sennheiser-hd-660s2","title":"Sennheiser HD 660S2 Open-Back Headphones","description":"\u003cp\u003eThe Sennheiser HD 660S2 is an open-back audiophile headphone with 42mm transducers and a 300-ohm impedance, tuned for a natural, relaxed presentation rather than a hyped one.\u003c\/p\u003e\u003cp\u003eThree hundred ohms is a real requirement, not a footnote — plan on a desktop amp with some voltage swing to hear the HD 660S2 properly. Open-back means it leaks both directions, so this is a quiet-room headphone: home listening, late evenings with a record, long sessions where fatigue matters more than isolation. The relaxed tuning is what makes those long sessions possible.\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003eOpen-back audiophile design\u003c\/li\u003e\n\u003cli\u003e42mm transducers, 300-ohm impedance\u003c\/li\u003e\n\u003cli\u003eNatural, relaxed tuning for long listening sessions\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003eAuthorized Sennheiser retailer, 45-day returns, 1-year warranty.\u003c\/p\u003e","brand":"Sennheiser","offers":[{"title":"Default","offer_id":45376695566471,"sku":"Sennheiser HD 660S2","price":458.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0756\/5833\/0247\/files\/7771179251.jpg?v=1785501858","url":"https:\/\/tonepier.com\/products\/sennheiser-hd-660s2","provider":"TonePier","version":"1.0","type":"link"}