The R-15PM, the topic of this thread, has the same drivers, etc, as the R-15M - it just has a 50 Wpc amp built-in. The 'equivalent' in driver size in the 'Reference Premier' line is the RP-150M. 'Desensitized' hearing? I thought, at 68, I just had 'mature' hearing! A lifetime of loud music - and not always using effective hearing protection when shooting firearms - have taken their toll on my hearing. Still - I recall being blown away by the first Klipschorns, with Heresy center, I heard - in 1971. Driven by three separate Dynaco 35W tube type mono amps, the sound was unreal - and loud - with no distortion. The R-15M's were oddly somewhat similar, as far as capable of higher volume levels without distortion is concerned. 'Horn's' just sound 'different'.