Sennheiser - Refurbished Excellent - HD 650 - Hi-Res Audiophile Open Back Headphone - Quality Transducer and Diaphragm - Gray - Black

The HD 650 has all of the perks of a high-performance sports car and none of the quirks. This open-back headphone is beloved by audiophiles for its musical, non-fatiguing sound while still offering intimate levels of detail. Upon the first note, your favorite tracks reveal their true potential, and each moment of that performance becomes an opportunity to react all over again. For the hi-fi enthusiast that prioritizes engaging sound quality the HD 650 is an instant upgrade. The HD 650’s signature sound starts with our in-house acoustics. Audiophiles know that the best components perform at their peak when nothing stands in their way. The 42mm transducer deploys a 38mm diaphragm with aluminum voice coil specifically tuned for extended, critical listening: overall treble and low-frequency presence are effortless while midrange is reproduced with lifelike composure—none sacrificing their organic roots to get there. Made in Ireland at our state-of-the-art production facility, the HD 650 delivers more: more details discovered, more musicality, and definitely more time for blissful listening.

The HD 560S indulges the audiophile evaluating their music’s entire journey through the audio path. With linear acoustics and exceptional low-frequency performance the HD 560S was crafted for the analytical audio enthusiast. This open-back headphone is tuned to reveal every detail in your music without sacrificing the gratifying bass response. When combined with its ultralight chassis and luxurious comfort, it’s a breakthrough value in reference monitoring.

Despite the HD 660S’s standing as one of the world’s popular audiophile headphones, some customers nevertheless wanted one very specific enhancement: even deeper bass. Because whether it’s a thunderous crescendo of timpani or the pulsating beat of electronic dance music, there is nothing like accurate, powerful sub bass to infuse your listening with drama. Audiophiles—and anyone looking for comfortable, non-fatiguing, high-end headphones—can now get even more impact and emotion from the HD 660S2. The headphone’s warm, relaxed tone is reflected by their timeless styling with elegant bronze accents. With its open-back design and outstanding comfort, the HD 660S2 is also destined to be a favorite for long listening sessions. This version builds on all the strengths of its formidable predecessor. The same world-class precision and resolution still let you pick out individual instruments like with no other headphone. Or experience the joy of discovering sonic details in recordings you’ve known for years—now underscored with more and deeper low end. Indeed, the standard-setter for extended listening has now become the standard-setter for extended bass as well. Enhancing this heralded audio design without detracting from its many strengths was, however, a daunting task. So, our engineers set out to systematically identify and exploit every opportunity in their quest to improve on the acclaimed HD 660S design. We adjusted the compliance of the surround, for instance, dropping the resonance frequency to 70 Hz. Considerable effort went into optimizing the airflow around the transducer. The coil in the HD 660S2 has also been revised to match the legendary HD 600 & 650, resulting in an impedance of 300 ohms. The coil offers a high magnetic force and electrical damping for a clean impulse response. It also increases sensitivity over the entire frequency spectrum by using the magnet’s air gap more efficiently. Taken together, these efforts and more have paid off in spades. Sound pressure at the lowest octaves has doubled. Now, you can feel the music more than ever before—with all the depth and weight that ultra-low frequencies invoke. The lowest A on the piano (27.5 Hz) or the pounding root note of a bass drum (45-60 Hz) are just as big, expansive, and imposing as if they were live. The unique combination of impactful bass combined with the warm tuning and smooth treble will be a revelation for audiophile listeners. It’s an even better way to lose yourself in comfortable, non-fatiguing, high-end sound—while feeling its full low-end power.