To state a fairly obvious point, I would just suggest that you make a point of including recordings having particularly wide dynamic range in your assessment. Such as many recordings of classical symphonic music, if you listen to that type of music. For a given average volume, recordings of music having narrow dynamic range and/or recordings that have been engineered with a lot of dynamic compression are of course less likely to reveal the issues Ralph and JSautter have referred to:) OK. These are all on LP.
Wagner Gutterdämmerung, London, Solti conducting, final scene (Immolation scene)Verdi Requiem Soria Series RCA, side 1 track 2 Dies Irae
Black Sabbath 'Paranoid' German white Vertigo press, side 1 track 1.Canto General America Insurrecta Atma-Sphere 3-001
Play any of these anywhere near a satisfying volume and that power problem is easily revealed.