You couldn't have picked a better handle to post under with this question.
To keep things fair and balanced - here's the counter-point to the view stated by the cable evangelicals:
If improvements from 3rd party headphone cables could be quantified (and this assumes they make any difference at all), these differences would show up in software like diffmaker (free at: http://www.libinst.com/Audio%20DiffMaker.htm ). We've batted this topic around in this thread for years now due to the number of folks shilling "must-have" aftermarket cables for the HD650's. Not a one of them has ever posted a single measurement demonstrating resulting audible differences.
The HD650's are great headphones, but they are not, by today's standards, reference grade when compared to the available TOTL options. No amp, dac or cable, or combination thereof, is going to make a conventional dynamic driver perform like a stat or like the patented ring drivers in the HD800's.
I absolutely agree with this, Skeptic. I'm sure my question may have been misleading, but I am someone who believes cables do not make a difference. I am just curious how others who do believe this (since the HD650's are one of the most popular headphones for aftermarket cabels) report their experience. Are they hearing a sound twice as good as before? 50% better? In this case, Phoebe reported more than a 40% improvement in sound quality.
My new HD650's are coming in tomorrow and I do not plan on ever replacing the cable on them.
Edited by fallingreason - 3/8/12 at 3:39pm