Why is it so easy to tell the difference between live and recorded music?

onhwy61, I've heard of similar demonstration (long time ago) with symphony orchestra and the best audio system available behind the curtain.  Herber Von Karajan, asked to participate, detected system with ease every time. When they asked him how different it sounded to him he said that record player was slowing down slightly during orchestra's forte.   Surprisingly famous musicians with such perfect hearing often don't care about the sound.

Not at all easy with large ATC to recognize the difference between live and a good recording. I think wide even dispersion and high dynamic range and a neutral uncolored sounding speaker are major factors but there is a lot that is required - so it is rare enough that I understand why many folks might think it would be impossible.

I have followed Steve for years and I think his technical knowledge is outstanding but his hearing preferences are towards colored hi-fi style sound. Nothing wrong with his tastes but you arent ever going to find realistic audio reproduction with those kind of preferences.

Limitless frequency and dynamic swings

I guess I should explain why wide even sound dispersion is critical. Maybe Steve will read this and learn something.

Our ears and brain are very good at integrating sound with the environment. A speaker that radiates evenly throughout the entire spectrum is like a conventional light bulb - it lights up the room evenly. A speaker that varies in radiation with frequency will give telltale signs to our ears - just like a spotlight produces a beam that is in one direction. When you couple sound with an environment like a room or space - again our ears instantly pick up on directional variations in sound and a spotlight or narrow beam over some frequencies is instantly recognizable even from the differences in reverberation from sound coming out a room window!!!

It is very similar to cupping hands over your mouth when speaking or using a megaphone to increase the directionality of the voice - we can hear this change in reverberant sound instantly.

So our ears brain are able to work out very quickly and easily that a beam of sound is NOT natural sounding. Only wide even dispersion sounds natural as it will evenly reflect off of the space around the sound source and the listener.

We are so good at this that standing in an acoustically treated totally dead room can make people feel sick - as the eyes and ears do not correlate what is seen with what is heard.

This is why horn speakers with uneven dispersion and a higher degree of directionality never sound natural except in a very small sweetspot and a nearfield seating position (this minimizes the uneven reverberation that makes it obvious that the sound is artificial).

AR chose small ensembles or solo instruments for their tests.  A symphony orchestra would be a far more challenging.

I don't think it's always easy to tell the difference since there have been specific occasions where I've been fooled, but in general, live sound reacts with background noises in a different manner than amplified music.  It floats above it as opposed to cutting through it.  Sorry for the obscure language.