One of the best tweaks I've made is to raise my speakers 1 inch using those auralex pads. I can't tell if the padding does anything (things certainly sound more detailed to me though and I seem to be able to put the volume up much higher without getting complaints) but I think just having the tweeters slightly above ear level makes a big difference in the smoothness of the speakers (I apologize for not being proficient with audiophile jargon)