You might want to use the following youtube clip for testing, which I believe is a good recording. Set up your speakers placement according to the actual stage and see if the SS within or beyond the speakers. Also close your eyes to feel the depth of the SS and how well each instrument is separated. In my living room where the side walls are not closed by, the SS created by my system is indeed wider than speakers and I could pinpoint the position of each performer. You need to move the speakers away from front wall to acquire the SS depth. You could also turn the speakers with slight toe-in angles to improve the images but not too much to affect the SS width.