parsons - ....the resulting PACE gives the impression of just the slightest, but very noticeable, perception of "slowing down" of a song that you know very well....
I heard (or believe I did) the subtlest of timing difference once in a Rolling Stones song when I first compared my Oppo to Yggy. That would be the timing between the Oppo vs Yggy, and it was during a vocal passage. At that time the Yggy wasn't broken-in by the standard of days/hours many state is required to sound optimum. My point is I understand what you're referring to regarding perception of timing (slow or fast) which is likely milliseconds and can only be perceived from tunes that your mind is accustomed to hearing many times throughout the years.
It seems reasonable to me that these types of tunes that one is accustomed to hearing for years would be studio recordings. In my case I listen to new (I haven't heard it even once) live recordings, which makes it impossible to detect the type timing anomalies that could result from break-in or DAC to DAC comparison.
