Can you hear bit rate?

@tonyrox 

Did any of you guys take the Dr. AIX test? 

I for one have no idea who Dr. AIX is, unless you mean Dynamic Range.

I found this discussion: AVS/AIX High-Resolution Audio Test: Ready, Set, Go! | AVS Forum and note that the opening post explicitly excludes DSD and SACD!

DSD was explicitly designed, by the original inventors of CD, to eliminate the linearity problem inherent in PCM.  

It is of course startlingly easy to compare CD quality and SACD quality because almost all SACDs include a full CD layer as well as 2-channel plus 5-channel SACD versions of the same recording.  You only need a system that can play these options.

So what is the linearity problem with PCM?  It is that each bit should contribute a precise amount to the output volume, but the contributions vary so dramatically in amount that the industry has spent 40 years coming up with improved, but not perfect, methods of doing so.

I have taken numbers shown below from Audio bit depth - Wikipedia

With 16-bit PCM, the range of values is −32,768 to +32,767.  The most significant bit should contribute 32,768 times as much as the least significant bit.  Furthermore, at the crossover point, there should be a monotonic change when the fifteen lesser bits switch off, and the most significant bit switches on.

Monotonicity means that the output should always increase as you move through the number range.

The numbers are even more fantastic (I mean that literally, we are in fantasy-land) with 24-bit.  The range of values is −8,388,608 to +8,388,607.  The most significant bit should contribute 8,388,608 times as much as the least significant bit.  In reality, we probably max out around 21-bits!

There’s also 32-bit.  (16, 24 and 32 are convenient multiples of the now ubiquitous 8-bit byte that computers are designed around - nothing magically related to audio at all).

With 32-bit, the range of values is −2,147,483,648 to +2,147,483,647.  The most significant bit should contribute 2,147,483,648 times as much as the least significant bit.  Wow.

DSD resolves the monotonicity electrical engineering dilemma beautifully.  Each bit should just nudge the output up or down by an identical amount.  DSD is what I believe we should be listening to when we talk about high resolution.

Caution: a lot of dacs do not natively handle DSD; DSD has to be down-converted to PCM (a lossy process) for such dacs to work

Benchmark Media (well-known DACs and amplifiers) offers at least two white papers from their library that discuss these matters:

What High-Resolution Audio is NOT - Benchmark Media Systems

Audio Myth -"DSD Provides a Direct Stream from A/D to D/A" - Benchmark Media Systems

@erik_squires 

I’m not sure how to answer your question.  When I listen to my SACD of Dire Straits, Brothers In Arms, it sounds noticeably fuller than my original CD.  Am I hearing DSD X1 or am I hearing somebody who monkeyed with levels and phase when making the SACD?  Some other SACD’s I have  sound worse than the Hi Rez I get on Qobuz and some sound better.  
 

@curiousjim 

You can bet your last dollar that Brothers in Arms was not originally recorded in DSD in 1984/1985.  DSD was not released until 1999.  There would have been lots of individually miked tracks to play with, though.

I think the 5.1 SACD soundtrack is superb - are you listening to the 2-channel SACD version?

Almost certainly, Brothers in Arms for the SACD release would have been mastered using the DXD format, also co-invented by Philips.

Many SACDs these days are originally recorded as high resolution PCM, including for example Chandos SACDs.  When converting high-resolution PCM to DSD, something has to guess where to space out the bits in time. Different guesses, different outcomes.

On the other hand, going from DSD to PCM is an exact calculation, when the frequencies are exact multiples, which is true for commercial recordings and why 2L.no archives in very high frequency DSD.

@sargonicuse 

Those papers you quoted are 10 years old!