Sennheiser HD 555chat_bubble_outlineFrom real comments

Sound quality is the headline strength of the HD 555. Users consistently describe the sound as clear, crisp, revealing, and spacious, with a wide soundstage that shines with lossless files and a decent amp or sound card. Several owners compared it favorably to competitors like Astro, Bose, and Beats, and even against pricier Sennheiser models like the HD 595 and HD 660S, noting only minor differences. It performs well for movies and acoustic music, though less so for heavy electronic genres.

Bass is polarizing but fixable with a known mod. Multiple listeners were surprised by the restrained bass out of the box, questioning if their unit was defective, while others appreciated the tight, low-key bass as appropriate for audiophile listening. A widely mentioned DIY mod—removing foam strips over the air holes—brings the bass and sound closer to the pricier HD 595, and is frequently recommended across comments.

Build durability and comfort show a mixed long-term picture. Many owners praise years of near-daily use (commonly 5-15+ years) with unchanged comfort and sound, and compatibility with glasses. However, a recurring issue is cracking plastic at the headband and yoke swivel, sometimes appearing within weeks of purchase for unlucky units. Being open-back, they also leak sound significantly, making them best suited to quiet, private listening environments.