Positioning Vandersteens

Jimspov, not sure if you bought new or used, but the manual gives a detailed procedure for setting the speakers up.  If you don't have the manual the Vandersteen website has one.  Assuming they are new, before making sound judgements let the speakers get at least 100 hours on them.  The other thing not stated is what effect does standing up give?  More high frequencies or less? If you like more high frequencies then the tilt needs to be less towards the rear.  If you like less high frequencies then the tilt needs to be more towards the rear, but be careful not to tilt too much!  Getting less high frequencies, though, may be an indication of something else not quite right, but that is too hard to elaborate on.

Ok, now it makes more sense.  If you are hearing better low end you are probably experiencing a "valley" in the response at your normal position and probably a close to flat response in the upright position.  I would suggest getting a test CD with distinct frequencies on it then put low frequency tracks on repeat and move around your listening position and even the whole room.  You may be amazed at how much variation there will be in volume.  This is the heart of why so many people say the room is the most important component.  Sometimes you get lucky, other times it's a chore to get a room sounding good.  Positioning the speakers is the first step, but more may be necessary.