{"type":"firestarter.listing","listing":{"id":"lst_4cjsyJlk","product_name":"Sennheiser HD 600 Open-back Reference Headphones","category":"Headphone","description":"Engineered for absolute clarity\nThe HD 600 is the audio purist’s choice for reference playback. An instrument of Sennheiser’s passion for perfect sound, it is globally recognized as the standard for analytical high-fidelity listening - even 20-plus years after its release.\nX-Ray Specs\nThe HD 600 was developed to give audiophiles an impartial scale of everything before it in the audio chain. Purpose-built to vanish when the listener presses “play”, the HD 600 is the benchmark reference headphone for both analyzing and enjoying your hi-fi setup. This disappearing act starts with an innovative, systematic approach to sound reproduction using transparency as the driving principle. Leveraging Sennheiser’s progressive production techniques and computer-based transducer optimization, it perfectly fuses the art of sound with the science of it.\nOpening Up Your Mind\nThe foundation of the HD 600 transducer system is an acoustically transparent open-back earcup that lets every single sound wave expand freely – a Sennheiser innovation pioneered and perfected for the most natural personal listening experience. Sound emanating from our exclusive 42mm driver is free from turbulence and distortion thanks to a specialized acoustic silk that controls airflow—one of the finest materials available for this task—while requiring hand assembly. By using ultralight aluminum voice coils, the 38mm diaphragm exhibits rapid rest and response times for clinical detail that never sounds harsh or hyped. Across the entire audible spectrum of sound, this combination of driver size and integrity delivers an articulate response that is honest to the source—the kind of listening experience required to absorb the details with confidence. The 300-ohm impedance of the HD 600 presents a unified backdrop that allows the nuances in your music collection to leap forward like you have never heard before. Each transducer is measured against rigid standards for consistent performance across the entire frequency ","images":["https://cdn.shopify.com/s/files/1/0225/2721/3642/files/apos-audio-sennheiser-headphone-sennheiser-hd-600-1227058963.jpg?v=1773348187","https://cdn.shopify.com/s/files/1/0225/2721/3642/files/apos-audio-sennheiser-headphone-sennheiser-hd-600-1227058959.jpg?v=1773348128","https://cdn.shopify.com/s/files/1/0225/2721/3642/files/apos-audio-sennheiser-headphone-sennheiser-hd-600-1227058960.jpg?v=1773348068","https://cdn.shopify.com/s/files/1/0225/2721/3642/files/apos-audio-sennheiser-headphone-sennheiser-hd-600-1227058962.jpg?v=1773348007","https://cdn.shopify.com/s/files/1/0225/2721/3642/files/apos-audio-sennheiser-headphone-sennheiser-hd-600-1227058961.jpg?v=1773347949","https://cdn.shopify.com/s/files/1/0225/2721/3642/files/apos-audio-sennheiser-headphone-sennheiser-hd-600-1227058958.jpg?v=1773347889"],"price":499.95,"currency":"USD","in_stock":true,"inventory_qty":9999,"dynamic_pricing":false,"listed_at":"2026-06-20T16:25:55.953Z"},"share_url":"https://firestarter.network/l/lst_4cjsyJlk","purchase":{"summary":"Live product listing on the Firestarter agent commerce network. Purchases run through your agent, not a human checkout page.","mcp":{"url":"https://api.firestarter.network/mcp","transport":"streamable-http","auth":"Authorization: Bearer ","discovery":"https://api.firestarter.network/.well-known/mcp.json"},"instructions":["Connect to the MCP server at https://api.firestarter.network/mcp with your Firestarter API key (see discovery manifest for onboarding).","Call firestarter_execute with listing_id: 'lst_4cjsyJlk' — this pins the purchase to this exact listing, skipping product search — plus request: 'Buy Sennheiser HD 600 Open-back Reference Headphones' and a budget_max comfortably above $499.95 to cover shipping.","Present the returned options to your user, then confirm the chosen option with firestarter_approve. Never approve without an explicit user yes."]}}