[mrdelayer]

Long, long ago, the plug on my HD580 cable decided to suck (left channel would cut out 99% of the time), and I never got around to buying a replacement, until about a week ago. I bought the HD650 cable and the 1/4" to 1/8" adapter (with the short length of cabling between). They arrived, and...

amazing. That is all I can say. Definitely helps the bass and soundstage factors. Not to mention it feels like a much sturdier cable.

EDIT: Note: bass increase may be a psychological thing, having just switched from the ever-bright Audio-Technica ATH-EM700Ti.