I actually think that we are basically arriving at the same conclusion but maybe only articulating it differently or have some slight different thoughts on the root issue? I should say that Hans B is my only reference since i trust him :-).

Here is how i understand him, on a high level:

The noise (different types of noise) in the ground plane are according to Hans B causing the square wave to change shape from I_I to instead look like this _/.  Hence the timing is off when converting to analogue, since the distance between those vertical lines are no-longer equal, The result is called jitter(?), in a DAC clock/dac context, but the actual cause of that jitter is the noise messing up those square waves, that no-longer is perfectly square.

The human hearing is exceptional at picking up those tiny timing related differences and the differences in timing are on pico second level, which we are not able to measure, yet.

Not sure why i write this down since i am not an expert... :-), but it felt nice to illustrate it in writing for myself.

Also, i am not claiming that you already "knew" about this. It is more to share how i think to see if it differs from your way.

I think that's a great illustration. I do that as well, writing it down and getting a better understanding my self 🙂  Hans for sure has far more knowledge on this matter.

May I add that we maybe should talk about datawords instead of bits for even better understanding. Let's look into the R2R dac for another moment. When we draw vertically a container for 24 bits and we will draw the single bits vertically under each other in this container. Then we will see the shapes of the actual 1's and 0's. Not one bit will have the exact shape of another, they are all different. Together they will go through the resistors and will be combined at the output. They represent a voltage together. When we put another dataword with exactly the same data in the containers, but again not one bit will have exactly the same shape as in the first data container, because the shapes of the bits are actually built analog. Still they represent the same digital data value(bit perfect). Still due to the analog shapes they will create a slight other output voltage.

Personally I think that this is what we hear and not the picosecond of time difference. I think our brain must deal with all sorts of reflections which it will correct to a certain level. Besides this an audioclock of 24.576 Mhz will only clock out once every 512 clock taps for a 48Khz file.

Thanks for sharing. I will have to read that a few times and let is soak in 🙂

I also like envisioning how we can "see" a holographic image, just re-created by pure sound. If one think about that, and the tolerances involved for our brain to re-create such a holographic imaging, then it is clear (to me) that our brain is amazing at compute sound based on timing. Otherwise this is not possible to recreate in our brain. Those timing tolerance is really amazing and makes sense to me if they are challenging to measure. Now this does of course not relate or explain your issue, but is more a way to illustrate why i think timing is incredible important as we convert from digital into analogue.

Of course 🙂 Keep in mind it's still just a theory

I came up with this theorie, because logically data bits that are not shaped well will limit high frequency response first. When a small amount of output voltage is missing on each clocktap due to badly shaped data, an analog audio waveform will have shorter spikes and because high frequencies are built with more spikes than low frequencies we will hear dark sound.