sorepinky - The methodology of the Boston Audio Study of 2007 (the first AES link) has been criticized over and over again. At this point, it has very little credibility with a large segment of the audio world.
The abstract of the second AES paper has an interesting comment, that bears thinking about :
"In addition to training, the research suggested that careful selection of stimuli, including use of long duration samples, may play an important role in the ability to discriminate. Studies that did not show an ability to discriminate were generally more prone to biases or flaws in their design"
The issue of short duration versus long duration testing methods has been discussed in this forum before. This paper seems to confirm the idea that long term listening may be a better methodology to use for audio comparisons. That methodology is seldom used. The "accepted" methodology is to use short, quick changes for comparisons, which, may, in fact, be bringing a bias into the experiment.
The comment on training is also interesting. Very few listening sessions are done with trained subjects. Certainly the ones that people report hear do not use trained subjects - trained in the way a researcher would train subjects.
One thing that gets left out of so many of these discussions is that different DACs sound different. Different PCM DACs sound different. Different DSD DACs sound different. In fact, many DACs are now offering different filter options so the user can check the one they like the best. So, if someone says they like DSD better than PCM (or vice versa) is may just be the particular DAC(s) and/or the particular filters they are using.
This discussion will go nowhere. Different people, with different systems, different hearing, different training, etc. will hear things differently. Some people believe that, some people do not.
My wife has incredible hearing. When we talk audio - and only when we talk audio
- I call her my "bat". I struggle to hear differences that she hears in seconds. She really can hear things only a bat can hear. What she says goes in my house, no matter what any AES paper says.
I would say the same thing often goes from people in the business. After spending their lives listening to music they can often quickly hear nuances that others cannot hear. I remember one listening session in which after a very short time a dealer said to me - "The second DAC brings the sound so much more forward", something I had not noticed until he said it. But it was quickly obvious to him.
We really need to recognize how differently we all hear our music.