In all such discussion, the following link appears at some point. And since I have not found it in the text, here it is, McGurk effect:
https://www.youtube.com/watch?v=G-lN8vWm3m0Do you still trust what you hear more then 0 and 1 (Boolean logic)?
Some small comments:
When I played back just one audio WAV file of a commercial track extracted from the CD (16 bit - 44Khz - converted to 16 bit 96Khz by SPLAT - and also imported - same upsample into Reaper - so source audio is 100% identical).
No, it is not...
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.
When using 16bit ASIO mode... dithering THEORETICALLY can be notices. Practically, that can happened in cases you are able to hear the difference in signal on the level of -80dB. That can be in 2 cases:
a) you significantly amplify the signal after it enters interface. F.e. you have -40dB overall level, so you turn output gain +30dB
b) you are genius or alien... happens

When using 24bit ASIO mode... The best ADCs are in fact 20bit and dithering affect the last bit only, so (useless) bit 24. Can someone hear the difference? Sure... in case digital amplification is used, which "shift" bits into meaningful for ADC zone.
But (related to the first comment), have you checked Re-sample mode options in Reaper? Default playback re-sample settings are adequate for noobs (like me), but probably have insufficient fidelity for your.
Also note that Reaper by default is not sample accurate. So in case you put a clip on Measure 2 and tempo is 132.5BPM, samples in the media are shifted compare to the project samples. What happens then depends from many factors. F.e. in recent alpha there is a change in Glue, it was preserving the shift before and now it is more Freeze/Render like. Also Reaper re-sampling approach depends from the source and the target rates, f.e. "44.1 -> 48" can be just interpolated while "44.1 -> 96" is extra processed (not 100% sure, but from the wave picture that is LPF). And that is with unchanged settings in preferences!
I did some tests between the last version of Sonar Platinum and the Cakewalk by BandLab.
I remember reading that CbB is compiled from the same source code. But may be Noel has managed to improve audio processing during 1 month working for BandLab, something he has not managed during previous 15+ years. Happens
PS. I do not claim people do not hear differences. I just wonder why most such people do not try to understand from where it comes... When someone publish examples/what is done exactly, other people can help to understand the origin. Can be overseen option, can be not so nice feature, can be a bug in software, but also can be McGurk effect.
Usual counter argumentation for such proposal "but then some bit-worries will try to point what I should do...". Well. If someone WANT (to believe) that DAWs sound different (even in case they technically do not), no one can help.
PSPS. When doing some comparisons, not only (and sometimes not) the top equipment plays the role, but deep understanding what is really happens behind the scene.
Imaging you compare the sound of 2 guitars. Make sense? Sure. But imagine during the comparison you play one guitar with finger (only) and another guitar with pick (only).
PSPSPS. Note that Pan law settings in Sonar and Reaper do not match exactly. For most (but not all) Sonar Pan law options there is an equivalent in Reaper, but that is not (!) just one option.