Analog versus Digital

May we need to realise that flat frequency responce from the brain of the artist to the brain of the listener applies only to analog systems?


Analog systems are linear which means they obey the principle of superposition at small signals.


The principle of superposition means that the output of the sum is equal to the sum of the outputs of any two signals input to the linear system. In fact this is the definition of a linear system.


Superposition makes the Fourier theorem or the Laplace Transform apply for predicting what the output of the system will be at any signal input.


Digital systems are not linear.


On analog systems distortion tends to zero as the amplitude of the signal tends to zero like all systems in nature that tend to be linear at small excitation.



On digital systems as the amplitude tends to zero, distortion tends to infinity.



Is this the reason why even the cheapest analog system sounds like music? As if real musical instruments are there.


Having said that, this post is being written while listening to a digitally mastered cassette. The system that recorded the music and plays it are both analog though. Signal path: Artists brain - Baroque Favorites cassette CBS MYT 42548 Maestro 40-42548 - JVC cassette player Nivico 9425W - ordinary half tiled kitchen - listener's brain


By examining the signal path there seems to be a medium impedance matching from artis's brain to listener's brain. I.e.:
Artists - recording hall - microphones - analog tape - digital tape - analog tape - inverse microphones or speakers - reproducing room - listener's brain


There is symmetry to the left and to the right of digital tape in the signal path.


The microvariations of the playback motor mechanism in this example may produce micro caressing to the basilar membrane of the listener as the whole frequency spectrum of the music micro varies of micro shifts.




References:


https://en.m.wikipedia.org/wiki/Superposition_principle


Design and investigation of a triode single ended audio frequency amplifier with no negative feedback - Y.N. Tsakiris - Final year project thesis for engineering electronics - University of Warwick - Department of Engineering - 1993


Information theory and Noise - Dr. Robert Pettifer lecture course notes - University of Warwick - Department of Physics - 1993


Engineering Circuit Analysis - Hayt Jr., Kemmerly


Introduction to System Dynamics - Shearer, Murphy, Richardson


Tubes vs Transistors, is there an audible difference? - Russel O. Hamm - Journal of the Audio Engineering Society