Breaking Down the Evidence
The main concern with empirical research is the collection of unbiased evidence. Researchers must carefully design the research while minimizing exposure to potential errors. In the scientific world, it is common that several scientists or researchers gather evidence simultaneously through the replication of the same study. In addition, a peer review is a primary tool in science that is used to validate the evidence provided in a study or research.
https://corporatefinanceinstitute.com/resources/knowledge/other/empirical-evidence/
Stolen from Wikipedia.
These methods yield only probabilities. Among scientific researchers, empirical evidence (as distinct from empirical research) refers to objective evidence that appears the same regardless of the observer. For example, a thermometer will not display different temperatures for each individual who observes it. Temperature, as measured by an accurate, well calibrated thermometer, is empirical evidence. By contrast, non-empirical evidence is subjective, depending on the observer. Following the previous example, observer A might truthfully report that a room is warm, while observer B might truthfully report that the same room is cool, though both observe the same reading on the thermometer. The use of empirical evidence negates this effect of personal (i.e., subjective) experience or time.
What this means is the answer to "do you like A better than B" could be considered non-empirical evidence. Being able to tell A and B apart would be empirical evidence. However, if B was a modified version of A, then it could be empirical depending on how the question was worded. I do feel this paragraph is a bit strict in its definition.
From bennpar.com
Anecdotal evidence is using your personal experiences and stories to illustrate your point. Empirical evidence is measured, unbiased, and replicable.
Without a designed experiment that removes bias, a listening test is nothing more than a personal experience and hence meet this test for anecdotal.
From study.com
Today's topic, anecdotal evidence, can be defined as testimony that something is true, false, related, or unrelated based on isolated examples of someone's personal experience. Anecdotal evidence is very popular in the advertising world. Every time you see a claim about a product's effectiveness based on a person's personal experience, the company is using anecdotal evidence to encourage sales.
Again, like almost every single uncontrolled listening test reported on Audiogon.
From yourdictionary.com
Based on casual observations or indications rather than rigorous or scientific analysis.
Again, like almost every reported listening test here.
Oxford English Dictionary:
(of an account) not necessarily true or reliable, because based on personal accounts rather than facts or research.
‘while there was much anecdotal evidence there was little hard fact’
So yes, I am quite confident in classifying almost all the reported listening experiences on this site as anecdotal.