My speakers sounded fine with a push-pull 65 watts per side tube amp, and in anticipation of obtaining a lower powered single ended tube amp I switched to a pair of well regarded higher efficiency speakers. I bought the amp (Dennis Had Fire Bottle…12 watts or something per side), was using the new speakers and thought…hmmm…not quite the high frequency extension I need, just tonally ho hum, and I really wanted them to sing...so I put the as yet unsold previous speakers back in with no expectations and wow…they sound astonishing. 2 lessons: Don’t buy any speakers you haven’t heard in person, and the second lesson I forget. The original speakers in this tale are Silverline Preludes, with 3.75" D'Appolito arrayed aluminum/magnesium woofers surrounding tweeters of the same metals. My theory about the Preludes is the narrow baffle images better, and the cabinet is very stiff since it's skinny (and thick)…2 REL subs cover the bass.