I have to be honest and write I’m having trouble keeping a straight face when I read about these minuscule differences in signal processing. Just from an engineering point of view it’s great to have some measurements.
Apart from those with exceptional hearing and apparently trained listeners (really, who wants to listen to their stereo to pick out differences in signal processing. Most people listen to the illusion of music.
Anyway, just say you manage to get an electrical signal that perfectly represents whatever is on the chosen media; at some point in order to be audible there has to be a conversion from electrical energy to mechanical energy. We do this by making a suspended cone, or plate vibrate in most instances. These vibrations create a pressure wave and when it reaches our ears and then our brain it may sound like what we call music.
So for example, take a bass driver. Usually it’s a cone made of a material that needs to be light enough to move without massive amounts of power. A perfect cone would not flex or distort on any part of it’s surface. They all do though. We can make reasonably uniform cones but they all are imperfect. These cones are suspended, in a frame on rolls of rubber at the front and often what is in effect a paper spring at the back. I’ll ignore the problems associated with the magnet, the pole piece and the air gap and the varying impedance of each drive unit. There are good matches but I have yet to see a perfect pair. The boxes we enclose these drivers in vibrate, act as capacitors in some cases, the internal pressure waves often interfere with each other. With some the baffles flex, the material densities of the materials used have variation. The temperature of the air effects the suspension of the cones etc etc and then we put these boxes in a room which sets up all sorts of nodes and refections that effect what we hear.
Yet, here we are, or some are, worrying about whether what to most is an inaudible amount of jitter and distortion effects the sound we hear.
It doesn’t matter how perfect you get the electrical signal once it reaches the conventional loudspeaker in a room and the conversion from electrical energy to sound waves happens all that perfection in the signal gets swamped by the imperfections in the loudspeaker.
Thankfully the brain can still piece the vibrations together and make it sound like music.
So, for Miska in particular who recounts years of listening for submarines, I’ve got something for you to think about. I used to work in R&D that made avionic equipment and the problem was rarely distortion or imperfect signals, the problem was how the brain interpreted what it received. Basically the brain ‘hears’ what it wants to or expects to hear. It’s well know problem in military communications and is equally applicable to audio reproduction for music. You hear what you expect to. Ask your wife if you have one; she’ll explain it to you.