Mike from Headfonia encapsulates the PK1 sound perfectly - "The Yuin takes the tonality of an analog, vacuum tube system. It's treble relaxed and soft, the mids sweet and lush, good punch on the midbass, and not so much low bass." Standing basses are exceptional and acoustic guitars resonate properly. The highs fall off toward the extreme end but pianos are well articulated and face melting guitar solos are still face melting. Vocals are the strong suit for these headphones. Male and female vocals sound clear and realistic.