Pioneer is renowned yes, but when it comes to headphones, they are not exactly competitive. Sure the build is nice, but when you can get the M Audio HDH50, which is also well built, while offering much better sound for a much lower price, what exactly is the extra several hundred dollars getting you?
https://www.innerfidelity.com/images/PioneerSEMaster1.pdf
Note the spike at 6kHz, the bass rolloff starting at 100Hz, and that absurd harmonic distortion. A poor show by any measure, and it is utterly laughable that a "renowned" manufacturer would charge hundreds of dollars for that.