Do well designed amplifiers (if rated for low impedance) double their power at lower output? For instance an amplifier rated at (completely making up numbers) 70/130/150, would it double at 30/60/120? Just curious if this is a relevant spec if you have a relatively low impedance speaker? For instance I have Contour 20’s which dip to around 2.9 ohms, if an amplifier can’t maintain consistent power even at moderate volumes should it be upgraded?