Upsampling MQA files to original resolution with sox will sound like the original resolution

[audiventory]

Thank you @soxr for your experiments. I think, it is useful information for better understanding of MQA issue.

 

All what I wrote in this post is hypothesys only. Probably in the further discussion we will find new reference points, based on new information.

 

If I uderstand correctly, that was said in the first post:

 

1. MQA file upsampling with certain resampling give sound, that similar (in several listners opinion) to allegedly original DXD file, on certain equipment.

 

2. Minimum phase filter give better for certain resampler (in @soxr opinion) sounding then linear phase filter of ht resampler.

 

3. Unfolding does not performed in this experiment.

 

 

In 1. and 2.:

 

1) many "certain" term. I suppose, that it is implementation issues.

 

2) I wrote "opinion" because there is not reference to exact experiment.

 

 

 

About 3.

 

If unfolding undone, so ultrasound isn't restored. As I remember, at MQA's highest frequency range placed folded information, that like to noise without unfolding, and after unfolding the spectrum like to original one.

 

That it is mean?

a) By currently proved information we can't hear above 16 ... 22 kHz.

b) Thus the folded information and ultrasound may be unlistenable.

Therefore upsampling to 384 kHz keep most important ( in my opinion according a) and b) ) audible information.

 

It is may be one of reasons why listeners don't hear difference between allegedly original DXD file and upsampled MQA file.

 

However, for more reliable objective knowledge (independent on number of experiments, participants) need serious professional double blind test with exact protocol: big number participants and tests, equipment and listening room(s) specification, methodics, etc.

 

However, such researches learn implementations rather (certain hardware, software) then [Upsampling vs. MQA].

 

Also I don't met before correct researches of minimum phase filter. Probably somebody can share protocols of such researches.

 

[audiventory]

There are only 2 researches of ultrasound, that noted, when audio is discussed:

 

1. Human perceived time resolution

 

2. Brain activity to ultrasound

 

But still I don't hear about researches that prove real ultrasound impact to subjectively perceived quality.

[audiventory]

13 hours ago, Miska said:

If you don't hear difference between hires and RedBook, you can of course always stick to RedBook.

 

There are 3 options:

 

1. Hear

2. Don't hear

3. Seems that I hear

 

Playback of ultrasound is not aim of hi-res (high sample rates).

 

And it is technically impossibly to compare different sample rates. Because it is comparison of implementations, not sample rates.

 

I always care about maximal safe objective (repeatable in certain conditions) evidences. Otherwise, I keep in mind the unproved things until coming of new information. Also I doubt in proven things, because there may be new information too.