Burn in question and evaluation before burn in

The discussion is veering towards the absurd. Are people seriously arguing that they can accurately compare the changes in the sound of high quality systems when separated by hundreds of hours of actual listening time? It can't be done. Memory is not that reliable. If a component takes 400 hours to fully settle in, that translates to 2 or 3 calendar months (assuming 3 or 4 hours/day of listening). There are too many variables involved for any reliable comparative conclusions to be drawn over such a time span.

Amstrod, simultaneously comparing two identical components with different usage hours would be revealing. I actually believe it would show burn-in as real, especially for mechanical transducers (speakers, cartridges, mics, etc.).

Armstrod, the approach you and Albertporter describe could actually be as good an approach as exist for determining overall system satisfaction, but it is not the only way and it certainly isn't foolproof. Short-term A/B listening is the best way to determine whether there's a difference between two audio signals. Longer term listening is probably much better at determining whether those differences are important to music reproduction. That's just my opinion based upon my listening experiences. As with anything, there will be people who are far better at doing something than I can, so I must admit to the possibility that those people can hear things and draw meaningful conclusion from data that I can't.