SciFiGuy

We can measure the amplitude and frequency errors of electrical signals and compare them to known limits of human hearing. Unless you are saying that we don't know what these limits are?

in properly designed audio electronics?

I would say that this is only true up until the time the electrical signal is inputted into our speakers. I am not very confident we can measure, with definitive certainty, the resultant waveform once it has been converted by our speakers.

In the case of the devices being talked about in the OP, we can measure the distortions and reference them to known limits of human distortion thresholds. Or, are you saying that we don't know what those limits are?

What, besides amplitude and frequency, defines a waveform?

Interesting read. As a new poster I like the summary idea for, prior to registering, I read through a plethora of posts which all kinda summarized the same things. To have one central thread I think is valuable for any new reader. Still, what I would also like to see are some posts that highlight measured differences in these devices - noting before/after performance numbers - so as not to solely rely on personal opinions.

But is this so? I ask because science clearly knows that music is defined by just two variables; amplitude and frequency. We have instruments that can measure both to levels that far exceed the limits of what humans can discern. Instruments can also measure other distortions, such as noise and phase irregularities, with similar accuracy levels. I guess what I am wondering is what distortions is science not measuring that the brain might be interpreting?