Performance Build Quality Comfort Value PRICE $299 AT A GLANCE Plus Two-way hybrid dual-driver design User-replaceable cables Two-year warranty Minus Resolution no match for all-armature in-ear designs THE VERDICT The PSB Speakers M4U 4 blocks a good amount of external noise, feels comfy, and sounds sweet. What’s not to like? PSB Speakers’ Paul Barton is a quick learner. After decades designing his company’s speakers, he jumped into headphones with the PSB M4U 2 full-size, noise-canceling ’phones. The M4U 2 was hailed by critics and consumers alike, and his next design for NAD, the Viso HP50, was even better, Barton was clearly on a roll. Now, with the M4U 4, Barton may be the first celebrated speaker designer to ever tackle crafting an in-ear headphone.