[Radio Wrangler]

Speaker power ratings is a very inexact science.

One wattage number doesn't cover it. 110W rated power, but at what frequency? That's enough power to quickly ruin tweeters if it's applied at a frequency which reaches them. All manufacturers are guilty of giving single, misleading numbers. Music and speech have a roll-off characteristic where higher frequency components are normally progressively less powerful.

So, is the amplifier hitting its end-stops at the level you're trying to drive these speakers, or are the speakers hitting their end-stops?

If the amplifier, current limiting could be coming into play, or the amplifier could simply be reaching the limits of its voltage swing. I'd assume voltage clipping is more likely as usually Japanese amps are switched for two pairs of speakers, so their design is pitched towards low-Z loads.

A shufti with an oscilloscope would show if the amp is flat-topping. If so, it doesn't really matter if it's hitting a current or voltage limit. That Rotel is styled to look much hunkier than its electronics delivers.

You could try it with a pair of headphones, suitably attenuated and with long enough cable to put you in another room. If you hear the distortion, blame the amp, if you don't it's definitely the speakers.

David