Even in my test after creating bounces from all four DAW's I then tested the same stereo mix in all 4 DAW's in order to check on the fact that they all played the same from each one and they did! (I had multiple computers at the time and I arranged to have the same interface attached to both so I could at least compare instantly between any two)
 
I suspect something is switched on that you don't know about.  Which is bad in my opinion because if that is the case it means that Sonar can have something hidden and activated.  This cannot happen in Studio One for example.  There is simply nothing inserted anywhere when you create a blank slate.   Dig much deeper and check things out carefully.  Are you using the same audio interface for your comparisons? I just don't believe it.  The same stereo mix should sound the same everywhere in any DAW.  
 
Really the only way to compare is to have two computers setup with different DAW's on each and exactly the same interface attached to both and switch from the audio outs that way.  Something I doubt you will be able to do.
 
If when you are making comparisons for example time elapses between one and the other then your test is not valid at all.  The time between one DAW and the other needs to instant.  If there is time involved e.g. you are comparing something that you are hearing in the present to something you heard in the past then that is also not valid either.  The brain can play tricks and make you think something is different. 

Soundwise
I also prefer Cakewalk's audio engine to the rest.
Don't be surprised, though, that majority of DAW users don't hear any difference and will come up with scientific facts proving that nobody is able to hear any difference at all.

They will always come with I have tested it theory. I can hear differences in DAWs it is very noticeable. Maybe those who use gadgets to prove theory should just close their eyes and listen. it's obvious. Anyway, Bandlab are playing games with me and making this simple DAW difficult to download. Good job I have Studio One 3 to go to

dappa1

Soundwise
I also prefer Cakewalk's audio engine to the rest.
Don't be surprised, though, that majority of DAW users don't hear any difference and will come up with scientific facts proving that nobody is able to hear any difference at all.

They will always come with I have tested it theory. I can hear differences in DAWs it is very noticeable. Maybe those who use gadgets to prove theory should just close their eyes and listen. it's obvious. Anyway, Bandlab are playing games with me and making this simple DAW difficult to download. Good job I have Studio One 3 to go to

This is just pure hocus pocus. You are seriously suggesting that scientific tests - i.e. a mathematical comparison of 0's and 1's - are less reliable than your ears? If two audio files are identical and they null then that's the end of the story - there is NO difference. None. Any difference you claim you hear is an auditory illusion, a figment of self delusion. 
 
Please tell me that you understand the basic concept that if two signals sound different then their underlying 0's and 1's are quantifiably different as well. Because I seriously suspect that some people here don't understand that basic fact. 

dappa1
 
They will always come with I have tested it theory. I can hear differences in DAWs it is very noticeable. Maybe those who use gadgets to prove theory should just close their eyes and listen. it's obvious. Anyway, Bandlab are playing games with me and making this simple DAW difficult to download. Good job I have Studio One 3 to go to

 
I am a total listening person.  Not gadget related at all.  In all my tests the only thing I did gadget wise was to ensure all the levels were identical.  Something that really needs to be done.
 
All my tests were purely listening and nothing else.  I agree this is the only way.  Not only that but on a beautiful set of monitors in a studio control room that had very controlled acoustics too.  Another thing that most people cannot set up.  Plus seamless switching which means no one actually knows when the switching is taking place.  If one DAW sounds SOOO much better than the other then good ears should pick this up easily.  I also had some very experienced and talented guys in the room too with great ears and were probably way better at production than many around here as well. Pros in fact.  They still had a very hard time picking anything.
 

The only differences you are hearing between DAW's is the use of their bundled plug-ins and things and settings with some plugs e.g. upsampling and a range of other issues for sure.  I agree. Logic has a certain sound when you are using all of their built in stuff for sure. And it is different to Studio One etc.
 
But not playing back a stereo mix though assuming there are no processes being applied anywhere. 
 

Jeff Evans
 Sonar's audio engine on some levels is actually inferior to some other DAW's in fact. 
  

Please elaborate. I personally only know of one difference and that is in the type of filter design used during sample rate conversion. The test data is quite old so it may not even be true any longer but for what ever reason Cakewalk used slightly different filter design choices than some of the other major DAWs. The overall 1kHZ signal spectral analysis and the resulting impulse characteristics were all so close that the DAWs that had better impulse responses (e.g. less ringing) generally had worse 1kHz spectral plots. It is always a trade off in design, best to go with what your gut is telling you. :-) IMHO all of it seems to be below the level of average hearing. Not to say there are not people on earth with very much above average hearing. 

Not in quality I was meaning.  I was thinking more true gapless performance which is something Sonar cannot fully do as well as other DAW's such as Studio One.

All the DAWs I've tested have nulled.

Jeff Evans
Even in my test after creating bounces from all four DAW's I then tested the same stereo mix in all 4 DAW's in order to check on the fact that they all played the same from each one and they did! (I had multiple computers at the time and I arranged to have the same interface attached to both so I could at least compare instantly between any two)
 
I suspect something is switched on that you don't know about.  Which is bad in my opinion because if that is the case it means that Sonar can have something hidden and activated.  This cannot happen in Studio One for example.  There is simply nothing inserted anywhere when you create a blank slate.   Dig much deeper and check things out carefully.  Are you using the same audio interface for your comparisons? I just don't believe it.  The same stereo mix should sound the same everywhere in any DAW.  
 
Really the only way to compare is to have two computers setup with different DAW's on each and exactly the same interface attached to both and switch from the audio outs that way.  Something I doubt you will be able to do.
 
If when you are making comparisons for example time elapses between one and the other then your test is not valid at all.  The time between one DAW and the other needs to instant.  If there is time involved e.g. you are comparing something that you are hearing in the present to something you heard in the past then that is also not valid either.  The brain can play tricks and make you think something is different. 

Same computer, same audio interface, speakers, cables, only difference is the DAW - takes only a few seconds for me to switch from one DAW to the other.
 
I admit in theory it should sound the same, but it doesn't.
 
I notice that CbB has certain options for dithering(or not) on playback, as well as similar options for the export of the rendered audio.
 
This, I think is where the difference may be coming from. In Reaper there are only dithering options on render, - any live playback defaults to whatever method Reaper uses to communicate with the Audio driver (ASIO), and there does not seem to be any way to change this in Reaper.
 
So for example you could decide in CbB to dither on render(export) while on playback you do not dither as audio is transferred to the audio interface.
 
I have no clue what dithering algorithm Reaper uses to dither to the audio interface in real time, during playback - as this is not stated anywhere to my current knowledge.
 
 
 

The difference in audio quality on playback is not like night and day, no not quite, but just that little bit for me to notice, and Reaper sounds somehow more glossy and shiny, but in a way that while more hi-fi makes me feel less comfortable with what it produces.
 
Until I tried out Cakewalk, I would never have thought that anything was amiss in Reaper. Hitherto it sounded fine and still does in Reaper but CbB simply sounds a shade more authentic - no sugar coating.
 
My suspicion is that CbB provides options for dithering on playback (or not) which could be the difference I am hearing - hitherto, the only user selectable options for dithering I have encountered in other DAW's has been limited to rendering (the actual creation of a mix track by the DAW). CbB provides options to dither or not - on playback as well as while rendering, and you can set these to different values.
 
I'll see what the effect of changing the realtime playback dither has on the sound of CbB, when I find a spare moment.