Originally Posted by SilverEars
What do you guys think about these videos from ESS technology?
I have not seen the first one, but the second (delta-sigma DACs) seems to claim that very low level (under -100 dBr peaks) noise can be made audible by the presence of much louder music, and backs it up with an analogy that a voice can be heard and understood even in the presence of overall louder broadband noise (like a waterfall). I do not think this is correct, because in the latter case, the reason why the voice is not masked by the noise is that the noise actually likely has a lower level in the narrow band (I think it is about 1/3 octave for masking) around the frequency of the voice, while it can still have a higher RMS level over the entire audio band. Noise density and overall noise level are not the same. On the other hand, for low level noise that is inaudible by itself at normal listening volume to become audible while much louder music is playing, it would require some kind of "inverse masking", which is not proven at all by the video.
Also, the competing DAC that is shown to have the problem is not named, nor is there any information provided on how common the issue is (assuming that it is audible in the first place); I suspect they intentionally picked a worst case example. So, it is overall mostly marketing for ESS products (audiophiles are scared off buying the competition, because they might have unmeasured but allegedly audible and disturbing artifacts), rather than useful concrete information.