Nailed it. It's all in the nuances, imaging, soundstage, etc. Once you hear (feel, see?) that holographic 3D soundstage/image and all its subtleties anything that interferes isn't a good thing. When you hear subtleties you've never heard before (sounds familiar eh?) it's possible we've made an improvement. More is not always necessarily better as you know from your post above.I believe you! Sometimes, for some differences, rapid A/B is EXCELLENT, particularly when comparing differences in tonality - they really jump out, in that context. For other differences, such as micro-dynamics and revealed detail, you won't be able to tell sh*t from rapid A/B. Many people have bought into the idea that switching time must be nearly instantaneous, because our 'audio memory' is supposedly just awful. Experiments 'prove' that point, but those experiments are only testing short-term memory, or sensory memory (even shorter term), not long term memory. Many, if not most audiophiles that have been around for awhile have realized that the best way to listen for subtle differences is to get good and used to a system, without any changes, for several weeks, and then make one change only, and listen. This relies on long-term memory of things you have heard before. If you hear new things on familiar recordings, chances are high that you've made an upgrade.
Like setting up speakers, the room, etc takes time, even weeks of listening sessions (upgrading?) or not takes real listening, this doesnt happen by rapid A/B'ing, even with speakers.
