I just got the HD400 Pro, which I happened to find at a lower price than the 560s, somehow. I've read occasional reports of driver matching issues. What would be a good way to check if the matching on my pair is within what's considered normal for a headphone of this price class? I know the usual sine sweep method over at audiocheck.net, but are there other tests you guys like to run on new headphones in general, to check for QC or build issues before a return window runs out?
Since you only want to check whether or not the R and L channels are matched well, a simple flat plate measurement device can work for that application.
Listening tests can help to know whether or not the delivered channel matching is grossly problematic or not, but a difference may not arise from a manufacturing defect if it arises from the interaction between the headphones and your own anatomy (head, ears, etc.).