Hi there Atmasphere,
Quick discussion on this point. As far as I am aware, any soundstage information should be part of the original recording. For an echo to sound realistic it needs to have a combination of characteristics. It should have a time delay, which corresponds to the distance to and from the reflection point, it should have an amplitude that corresponds to the amplitude of the original sound, less losses for the distance travelled and it should have a frequency spectrum related to the original sound, with losses caused by the distance travelled and the resulting loss of amplitude. But we also need to remember that in music an echo isn’t a one time event….music is continuous so therefore is the echo, so ultimately the echo becomes a low amplitude, delayed part of the signal….in other words a signal colouration.
And its that colouration that imparts the characteristic of the venue on the music. For example, music played in a large, reverberant church will sound echoey, while jazz played in an intimate venue will have a very impactful and dynamic character with little or no echo but a lot of energy. That’s the recording…..the soundwaves that leave the loudspeakers and impinge on your ears. Now add the reflected back wave from the loudspeakers, which will have a delay and decay related to the listening room size that is in no way related to the actual performance venue. Worse, the back wave will be exactly the same for every single recording, so in essence its simply a non-correlated reflection that interferes with and blurs the recording’s natural ambience.….Essentially one gets 2 soundstages….that which is embedded in the recording and different for every album or even every track plus the overlay of fixed room echo, which is applied uniformly to every recording.