I don’t know if I would say the word hardest, but I definitely feel like I can keep turning it up, and the speakers never really show any signs of complaining… like if I turned the RF7 way up (for example) that I used to own….at a certain point you could definitely start hearing something would start complaining…..whether it was the speakers, the amplifier, or my ears. (I don’t know)… but with the 396 I never really feel like anything is reaching a critical point. Almost like a car that you don’t even realize you’re going 110mph until you look at the speedometer.