@jeffreyw
if the speakers are fairly new you can expect better bass from them as they accumulate hours- ~ 200 + or so and the bass will peak. also if new try playing some music with powerful bass for 24 hours continuously to help break them in much like REL recommends for subwoofer break in.
also- are you following the manual for speaker positioning? this includes maximum stand height of 24" so that the bass is reinforced by the floor and the treble becomes smoother when the tweeters are lower than ear level- this is by design and they need to be closer to the floor than usual.
the distance from rear wall, and port plug options are also important-. try to give them some distance to the rear wall and remove any port plugs - again according to the manual for distance from the wall and port plug options.
another thing to adjust is toe angle. the LS50s like to be aimed straight ahead, not aimed at your ears.
finally the quality of the stands, feet and interface to the speakers are all important. good quality solid, mass filled (e.g. Skylan, Sound Anchors) firmly spiked to the floor and using the KEF supplied rubber "feet" on the speakers help to make the bass more solid. the effect that a quality stand has on the bass is often overlooked until you hear it, then you are convinced.
peace and good luck.
