Unless you have bad hearing everyone would be able to hear the difference on speakers and live unless live is defined as someone playing far away on a scene or something, no matter how expensive equipment you have. It is impossible to have it sound like musicians playing in the same room. To even come close you would need several speakers per instrument playing in multiple directions and some playing sounds of the people moving, breathing and talking too. Not even a simple snare drum being hit at intervals can be reproduced by a normal stereo setup to sound as if it were in the same room unless it's at distance. Remember, we play music at home so the definition should be an orchestra two to three meters away, not an orchestra ten to twenty meters away up at a scene.
Someone with something to sell is a very unreliable source btw.