Meridian, which makes money from the adoption of MQA, states that there are audible benefits to their MQA processing over unprocessed CD quality, even
to some degree without a decoder being used during playback. For example, here
"No decoder? You don’t need a decoder to enjoy our ‘standard’ sound quality – which is now widely agreed by mastering communities to be superior to CD."
"According to MQA Ltd, playing the un-decoded version still enables the consumer to benefit from the deblurring processes used in the creation or folding of the track. "
Also in this interview
with their founder, Bob Stuart:
"One thing we haven’t talked about is backward compatibility. . . . If you don’t have a decoder, you can play it back without a decoder because it is PCM. MQA turns PCM into PCM. When you play it back, it’ll play back on a legacy system sounding better than a CD. . . . So you get great sound on legacy players, and it means that you can take the single mechanical and put it in your car, you can put it in Sonos, you can put it in iTunes, you can put it on a phone, and get better-than-CD quality."
He's right about one thing. If you have a good ear like I do, perhaps from having sold very expensive, top-flight, audiophile-grade gear for literally decades, it does
indeed sound different. MQA sounds worse and here's the proof:
[^Each vertical mark is a 6 dB increment. Frequency in Hz is shown across the bottom of the graph.]
I am indebted to the measurements of the Meridian Explorer2 performed by Archimago. His original work I took these screen grabs from here:
Or search for this MQA decoding device by name at his blog if the link expires.
Speaking of authentication, anyone can verify my double-blind, Foobar ABX test log and my resulting perfect 10/10 score, by cutting and pasting it in its entirety, meaning including "foo_abx 2.0.1 report" at the very beginning and concluding with the signature number:
And inserting this entire copied text into the signature check verification page
to be sure it is valid and has not been tampered with.