I thought I'd done the laymen thing already, and as you'll probably see, I may still fail at that yet...........As said above by MSB (posted by perhaps an F-14 pilot?), interpolation occurs when voltage amplitude values are APPROXIMATED during this up-conversion from CD resolution data, to much HIGHER resolution data. It's sort of like a line doubler for video projectors...sort of, but not exactly..................I think of it in this simple way: the conversion of the audio data, in the digital domain, to a higher bit and sampling rate (upsampling), allow the high performance DAC to do its conversion on this LARGE amount of data, thus making full use of the DAC's superior resolution. IT'S NOT A MATTER OF CREATING NEW DETAILS IN THE RECORDING that were never there to begin with, it's a matter of getting the most out of what was always there...just like everything else in this hobby.......................It's also not merely "digital" we're talking about, but rather how the digital data gets turned into the analog voltages/waveforms...before it goes to your amp, or preamp. THAT'S ALWAYS THE MOST IMPORTANT THING IN DIGITAL AUDIO. Otherwise, you're making assumptions like my smug, MIT graduated, aeronautical engineer uncle. He's said the cliche right to my face, "but digital is digital; how could one CD player possibly sound different from another one?" You know, the old/stupid "bits is bits" argument, only he didn't even bother to think of it on that level............No DAC is perfect, but it is the critical "roadblock-weaklink" in the digital playback chain. Therefore, if you can make use of a "superDAC" on "mere" CD audio, it's much better than using DACs that operate only on the level of "CD quality" data................Anyway, audio is always about maximizing your UPSTREAM performance, in order to make full use of what you have DOWNSTREAM. UPSAMPLING "guesses" at many extra millions of possible "loudness" levels (and frequency "pulses" in time) in the digital data, BEFORE IT EVER GETS TO THE DAC (that needs all the "help" it can get)..............As perhaps most who'll read this know, SACD uses a different digital process, that samples at nearly 3 million times a second, and only uses one "loudness" bit, to tell if the waveform is rising or falling. It depends on the sheer density of those 2.8 million pulses every second, to describe how quiet or how loud the music is...............It's all much more complicated than this, but oh well, I'm not the real expert here...either from a designer's viewpoint, or from a journalist's viewpoint.
