The Sennheiser HD 660S headphones are a great choice for those seeking well-built, open-back headphones with a comfortable fit, courtesy of their plush microfiber-like material.
However, individuals with larger heads may find them slightly tight due to their clamping force. These wired headphones tend to leak sound, as their open-back design and absence of ANC allow outside noise to penetrate.
Sound-wise, the headphones offer a more subdued bass and treble response, making them less suitable for bass-heavy music enthusiasts.
Moreover, their larger size and lack of a case make them less portable, while the absence of audio playback controls means users must rely on their connected source device for adjustments.