This kind of auditioning is very difficult and time-consuming and you usually end up with a subjective consensus of what "sounds best," and it's different every time.
I know I'm coming a little late to this discussion and perhaps when I read farther this point will have been brought up but...
If a group of you couldn't come up with a consistent opinion of which cables were better and that opinion varied each time you a-b'd cables, wouldn't that suggest that there was no discernible difference?
No, I'm serious. Since subjective data is prone to biases you need to account for it. So, how do you do it?
You don't. It's subjective.
1. based on or influenced by personal feelings, tastes, or opinions : his views are highly subjective. Contrasted with objective.
dependent on the mind or on an individual's perception for its existence.