There are a couple of
new reports of analog output problems with the Master Edition: "mids completely muffled and unclear due to so much bass with a sort of strange reverb", "way more bass than usual. Sound is also muffled a little bit with muffled high tones too". One says transport only using external DAC is fine, so possibly something on the internal DAC / analog side. If not system related to specific amplifiers, setup, etc. or just hypercritical impressions, hopefully isolated to only a few units.
What would be the best engineering / scientific tests for those with suitable software and/or instrumentation to see these reported issues if present?